LT5 Cooling and Radiators

[Dynomite]

A lot of guys get caught in traffic on HOT 100 deg F days observing the temperature gauge move toward the cross hatch area (230 deg F +). That seems to be typical of the Cooling System for the LT5 in traffic with AC ON. And those High Engine Coolant temperatures often caused by trash between the AC Condenser, Oil Cooler or Radiator or trash on ALL three. Especially if there is any oil film on the Oil Cooler.

I am installing my third Ron Davis Radiator tomorrow in what was suppose to be my Stock 1990 in CA.....did the same to what was suppose to be my Stock 1990 in SD.

I will take the 1990 for a run when it is 100 deg F ambient today with stock radiator and then another run tomorrow in 100 deg F ambient with the Ron Davis. Including idling as in sitting at a stop light for both (Stock and Ron Davis) with air on and off to see what maximum coolant temperatures are like for both Stock and Ron Davis.

With both fans running, my Fluidyne is keeping coolant temps at 90C at idle in 95F weather.

Yesterday took a 1991 with Ron Davis Radiator for a cruise with 95 deg F ambient and Coolant stayed around 194 F cruise (60 mph) and rose to 206 F with Air On Idling. This using the Fan Controls for Digital Read Out of Coolant Temperatures.

This testing with the same identical AC Condenser, Same identical Oil Cooler, Same Identical Coolant Fans and same identical 180 deg Thermostat.

The objective here is to create a baseline of simple testing criteria to determine how ZR1 radiators (1990 and 1991) will function cruising and in traffic (idling). The simple baseline criteria are 100 deg ambient temperatures, 180 deg thermostat, and functioning AC.

If you want to test radiators....this is the time here in central CA :D
Jun 16
Hot with plenty of sunshine
98°Lo 61°
Jun 17
Blazing sunshine and hot
101°Lo 63° more
Jun 18
Blazing sunshine and hot
101°Lo 62° more
Jun 19
Hot with plenty of sunshine
100°Lo 64° more
Jun 20
Hot with blazing sunshine
103°Lo 66° more

Note:

Engine RPM.

My experience in all ambient temperatures.

A. In sixth gear running 65 mph (less than 2,000 rpm) the Coolant always gets a bit over 200 deg F. On Hot days the coolant will get a bit over 213 deg F. The key is the Water Pump is not pushing enough flow through the fully open thermostat to cool the engine to a Temperature where the Thermostat takes over (180 deg F).

B. If I shift to 5th gear at 65 mph (more than 2,000 rpm) the coolant temperature drops to Thermostat control (180 deg F) on cool days and drops to near 200 deg F on Hot days.

My findings are simply that the stock water pump is a bit low on coolant flow rate at rpms under 2,000 rpm. As you can see there is a big jump in Coolant Pump Flow rate between 1,000 rpm and 2,000 rpm and it is in this area or engine RPM that the Coolant Flow Rate is not sufficient in HOT Climates when the ZR-1 is moving in 6th gear at 65 mph.

The overheating issue when idling at a stop sign on HOT days (100 deg +) is more related to Fan Air Flow.
Tests at 50 deg F ambient.
Going 65 mph in 6th (1500 rpm) coolant temperature 205 deg F.
Going 65 mph in 5th (2200 rpm) coolant temperature 192 deg F.
Idling at 750 rpm coolant temperature 204 deg F.
Engine rpm 2000 rpm (not moving) coolant temperature rose to 213 deg F.

So...….At 65 mph it is the coolant flow. At 0 mph (Not moving with rpm at 2,000) it is the air flow.

If I could get the air flow higher while in traffic the issue would then be the coolant flow again where keeping rpm above 2,000 rpm would solve the High coolant temperatures on hot days in traffic.
The Coolant Pump Flow at 800 rpm is 15 gpm. The Coolant Pump actually gets more efficient as the rpm increases from idle to 2,000 rpm.
As Per Marc Haibeck graph provided to the ZR-1 Net email list by Graham Behan about ten years ago, the Coolant Pump flow rate through the engine (not the radiator or thermostat) is:
15 gpm at 800 rpm
18 gpm at 1,000 rpm,
44 gpm at 2,000 rpm,
65 gpm at 3,000 rpm,
90 gpm at 4.000 rpm,
120 gpm at 5,000 rpm at which time cavitation is starting.

NOTE:

See the following post for a complete update regarding Engine RPM.

Post 7 - Thermostats, Fans, Water Pump, and Radiators (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp.html#post1580070558)

[RussMcB]

Good timing for me. I am shopping for improved cooling.

What is the Ron Davis model number, and how does its price compare to the Dewitts "drop in" model?

I've heard good things about the RD unit, and I've heard (very recently from one of our respected tuner vendors) that they've started using the Dewitts radiator instead because it cools as well and doesn't require modifications (shroud trimming).

I also read (in this post from 2002*), that the Ron Davis generic Chevy NASCAR model can be purchased for much less ($300?), works well, but requires slightly more mods (like maybe a longer hose - maybe splicing in a short straight section of pipe).

http://www.corvetteforum.com/forums/c4-tech-performance/296834-best-radiator-griffin-vs-ron-davis.html#post2867027

[Dynomite]

Good timing for me. I am shopping for improved cooling.

What is the Ron Davis model number, and how does its price compare to the Dewitts "drop in" model?

I've heard good things about the RD unit, and I've heard (very recently from one of our respected tuner vendors) that they've started using the Dewitts radiator instead because it cools as well and doesn't require modifications (shroud trimming).

I also read (in threads a few years old), that the Ron Davis generic Chevy NASCAR model can be purchased for much less ($300?), works well, but requires slightly more mods (like maybe a longer hose - maybe splicing in a short straight section of pipe).

See Installing a Ron Davis Radiator and Testing (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-9.html#post1588412806)

1. Ron Davis Radiator.
I little expensive at a bit over $600 and you have to trim the fan baffles 1/2 inch (the center part that sticks out further) about a 30 minute job. The Ron Davis then fits right in.

Ron Davis Radiator w/o transmission cooling

Coolant temperature stays at a constant 185 deg (70 deg F ambient) with 180 deg thermostat.*
a. 1989-1996 C4 Type V8 All Part No. 1-16CV8996
b. Rated 800 Hp
c. Manual transmission
* Coolant Temperatures will climb a bit to the Fan Off Coolant Temperatures (200 deg F) with AC on (100 deg F ambient) See testing below.

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite12/8bd68add-fcb2-4c2e-abf0-c1ed7f69573b.jpg

2. Ron Davis Radiator Installation.

First....Drain Coolant from system and remove Air Cleaner, Air Cleaner Housing.
A. Removed Oil Cooler Adapter from Oil Cooler.
B. Removed three 10 mm bolts bottom Fan Housing.
C. Disconnect the two fans electrical.
D. Remove two 10 mm nuts and one 13 mm bolt on Passenger Side.
E. Remove one 10 mm nut and one 13 mm bolt on Drivers Side.
F. Remove two 10 mm horizontal bolts on Drivers side.
G. Remove two 10 mm horizontal bolts on Drivers side holding ??? to Drivers side of Radiator Shroud.
H. Disconnect Temp Sensor bottom of Shroud.
I. Remove five 10 mm bolts top Fan Housing.
J. Remove three 7 mm bolts left and right bottom side of Shroud.
K. Disconnect Vent coolant overflow hose top Passenger Side.
L. Lift Drivers Side Shroud clear of Hood Hindge.
L. Lift Passenger Side Shroud bending the lower tab up and around AC lines.
M. Lift and remove Fans.
N. Disconnect Top Radiator Hose.
O. Remove three 13mm bolts from Thermostat Housing (More Coolant will drain from the system).
P. Loosen short radiator Hose between Thermostat Housing and Radiator (Twist).
Q. Remove Thermostat and remove Thermostat Housing Half that was connected to Radiator.
R. Lift and remove Radiator.
S. Clean Oil Cooler, AC Condenser, and bottom of Radiator Housing.

Disconnect Oil Cooler Adapter .......................................Remove Shroud lifting Drivers Side First
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite12/ec1c912c-d9b6-46f9-8d37-eaaf5a91560a.jpghttp://i287.photobucket.com/albums/ll142/dynomite007/Dynomite12/a4aeaacb-69bf-4ed1-8d15-250f05a653b6.jpg

Lift out Stock Radiator followed by Fans........................Trim center parts of Fan Housing 1/2 inch
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite12/7d64a5f1-6485-4219-b875-d6404a2994b5.jpghttp://i287.photobucket.com/albums/ll142/dynomite007/Dynomite12/66b1a4c7-30fc-4c55-90b0-330594d3dd4b.jpg

Install Fans followed by Ron Davis Radiator and Shroud
http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite12/c6f93933-0730-4bc6-a57b-48ec92af70e3.jpg

3. Baseline Stock Radiator Testing at 100 deg F ambient temperature and 180 deg Thermostat (Fans on at 205 deg F and off at 200 deg F).
Testing a 1990 ZR1 with stock radiator (AC Condenser, Oil Cooler, Radiator Clean) at 100 deg F ambient temperature. Using Fan Controls for digital readout of coolant temperatures. Coolant mix is identical for the stock radiator and the Ron Davis Radiator.

Cruising 60 mph in 5th gear (AC Full ON fans at speed 10) coolant temperature 225 deg F
Did not cruise with AC OFF as temperature of coolant is not prohibitive.
Idling (AC Full ON fans at speed 10) coolant temperature 235 deg F
Idling (AC OFF) coolant temperature 230 deg F

4. Ron Davis Radiator Testing at 100 deg F ambient temperature and 180 deg Thermostat (Fans on at 205 deg F and off at 200 deg F).
Testing a 1990 ZR1 with Ron Davis radiator (AC Condenser, Oil Cooler Clean) Using Fan Controls for digital readout of coolant temperatures. Coolant mix will be identical for the stock radiator and the Ron Davis Radiator.

Cruising 60 mph in 5th gear (AC Full ON fans at speed 10) coolant temperature 197 deg F
Idling (AC Full ON fans at speed 10) coolant temperature 213 deg F
Did not cruise with AC OFF as temperature of coolant is not prohibitive.
Idling (AC OFF) coolant temperature 208 deg F

5. Testing of 1991 ZR1 with Ron Davis Radiator and 180 deg Thermostat (Fans on at 205 deg F and off at 200 deg F).
The 1991 ZR1 with Ron Davis Radiator, AC Full On, and 100 deg F ambient temperatures the Coolant temperatures stayed around 197 F cruise in 5th gear (60 mph) and rose to 213 F with AC Full On Idling (208 deg F with AC Off). This using the Fan Controls for Digital Read Out of Coolant Temperatures.

The testing of the 1991 ZR1 was conducted with identical Ron Davis Radiator with the identical AC Condenser, Oil Cooler, Coolant Fans and identical 180 deg Thermostat. The ambient temperature was 100 deg F. The 1991 ZR1 has SW Off Road Exhaust as compared to the 1990 ZR1 with Stock Exhaust.

6. Summary of Ron Davis Radiator Testing using a 1990 and 1991 ZR1 in HOT ambient temperatures cruising and in traffic (idling).

The objective here is to create a baseline of simple testing criteria to determine how ZR1 radiators (1990 and 1991) will function cruising and in traffic (idling). The simple baseline criteria are 100 deg ambient temperatures, 180 deg thermostat, and functioning AC.

Both the 1991 and the 1990 ZR1 Coolant temperatures on a HOT Day (100 deg F ambient) behaved the same with both Coolant Systems settling in at 197 deg F cruising at 60 mph in 5th gear with AC Full On. At a long term idling (more than 15 minutes) the coolant temperatures settled in at 213 deg F with AC Full On. With AC OFF the coolant temperatures dropped to 208 deg F.

[Tyler Townsley]

Any chance of trying a 200 deg oil cooler thermistor instead of the stock 240 unit in your testing? I have not investigated who makes them and their ranges. I added 4 12 v ( 2 per side) computer fans to the wheel wells on mine. It made a difference but I have made a comparison yet. The oiler cooler system does not open with a stock thermistor until 235-240 degrees which kind of makes it useless.

Tyler

[Dynomite]

Any chance of trying a 200 deg oil cooler thermistor instead of the stock 240 unit in your testing? I have not investigated who makes them and their ranges. I added 4 12 v ( 2 per side) computer fans to the wheel wells on mine. It made a difference but I have made a comparison yet. The oiler cooler system does not open with a stock thermistor until 235-240 degrees which kind of makes it useless.

Tyler

I am installing the Ron Davis tomorrow so would not have time to see what the 200 deg oil cooler thermistor does with the stock radiator. I am of the thinking that air flow is significant contributor to cooling the LT5 and Daryll (Goldcylon) is on to the solution with higher flow rate Spall fans. And yourself with the additional air flow in the engine compartment. I recall Daryll also has an after market aluminum radiator installed. Daryll might post up some cruising and idling coolant temperature information on one of those 100 deg F AZ days....even say a 115 deg F AZ day .....including specifics on the radiator and cooling fans :D

I do know after market aluminum radiators do make a difference but I think higher air flow would also contribute to a real solution given I get a temperature drop of 10 degrees F just by the moving air flow cruising. Comparing the 1991 with Ron Davis and the 1990 with stock radiator I did find close to a 30-35 deg F difference cruising and idling although the 1991 was tested on a 5 deg F cooler day.

I know it will be 100 deg F tomorrow within a degree so my test tomorrow will be identical regarding ambient temperature and regarding AC Condenser, Oil Cooler, Thermostat and even coolant mix.

If (tomorrow) I get coolant temperatures cruising with AC on in the range of 190 deg F and in the coolant temperatures in the range of say 210 deg F idling I would say After Market Aluminum Radiators are the answer.

[Paul Workman]

Ahem....

'Case you can't do ºC to ºF in your head...

http://i185.photobucket.com/albums/x220/6PPC_bucket/tech%20files/celsius_to_fahrenheit_conversion_table_zpstnrznbgz .png (http://s185.photobucket.com/user/6PPC_bucket/media/tech%20files/celsius_to_fahrenheit_conversion_table_zpstnrznbgz .png.html)

...this might be worth cutting and pasting!:)

[QB93Z]

I like your approach, Cliff

On a few occasions, I had cooling problems in my high mileage, 1994 Yellow ZR-1 with the original radiator. The problems occurred when I was stuck in stop and go traffic on a hot day. These conditions match the test condition Cliff is describing.

In March 2014, in preparation for our 30-day trip to the Southwest, I tried to clean the radiator of debris by blowing compressed air through from the back (fan side). I decided that the cleaning method was not working very well so I chose to remove the radiator from the car so I could clean it more completely and straighten some fins that I bent trying to use the compressed air.

With the radiator out of the car it was obvious that there was debris stuck in the fins. The best way I found to remove it was to lay the radiator flat on the driveway, lift it about 3 inches and slam it down on the concrete. Each time I did this, I got a debris pattern of fine, grit like fine sand, that matched the circles of the two fans. I repeated the mechanical shock cleaning many times until the grit was mostly gone. I straightened the fins and reinstalled the radiator.

With the cleaned, original, 150,000 mile radiator, the cooling system, is working fine. I had no problems in the Southwest or on any trip since.

I believe that any cooling system analysis needs to address the air flow through the radiator. Based on the conditions of my radiator, I doubt that even an additional fan or higher flow fans would have helped.

Thinking back, based on the time it took to clean the radiator, it might have been better to just install a replacement radiator. At the time, I was interested in seeing if I could "solve the problem". On other ZR-1's, I have installed both the DeWitts and the Ron Davis radiators.

Jim

[RussMcB]

<snip> ... The oiler cooler system does not open with a stock thermistor until 235-240 degrees which kind of makes it useless. A thought: One possible benefit of a late opening oil cooler is cooler air to the radiator when the oil temp is below 235-240. If the oil cooler opened sooner, it would heat the air getting to the radiator.

[Dynomite]

I can do that conversion in my head (9/5 +32) and I have a nice APP on my cell phone (C to F) called Measures which also has a well used inches to millimeters conversion......AND....on the cell phone it is right there in my pocket (wrench in left hand and measures in right hand)......and/or Paul's phone number in right hand :D

If you forget 9/5+32 C to F just remember water boils at 100 deg C and 212 deg F........9/5 of 100 is 180 (20x9) +32 is 212. OK Paul....and that I can do in my head :D

Now.....doing Calculas in my head is another story (Area under the Power Curve for example) but I can calculate areas of triangles and rectangles in my head :sign10:

A Stephen Hawking I am NOT.....he does everything in his head which is pretty amazing for sure :thumbsup:

Ahem....

'Case you can't do ºC to ºF in your head...

...this might be worth cutting and pasting!:)

Thinking back, based on the time it took to clean the radiator, it might have been better to just install a replacement radiator. At the time, I was interested in seeing if I could "solve the problem". On other ZR-1's, I have installed both the DeWitts and the Ron Davis radiators.

Jim

Excellent write up there Jim and I think you have hit on the dilemma.....buy new Aluminum after Market or stay with well cleaned stock risking possible radiator leaks in an old radiator later on. I think the Aftermarket Aluminum Radiator may have a bit more cooling capacity with the same air flow.

Also might add that your cleaning procedure is right on and should be applied to AC Condenser as well as the Oil Cooler.

Especially the Oil Cooler sometimes accumulates an Oily Film (from where I am not sure) which contributes greatly to reducing the Air Flow through the Oil Cooler and as a result through the Radiator. A good degreaser sprayed on the Oil Cooler helps clean the Oil Cooler.

And I am sure you have the Radiator Debree Screen to stop larger obstructions such as leaves and that plastic bag that floats up from the pavement ;)

[WARP TEN]

I like your approach, Cliff

On a few occasions, I had cooling problems in my high mileage, 1994 Yellow ZR-1 with the original radiator. The problems occurred when I was stuck in stop and go traffic on a hot day. These conditions match the test condition Cliff is describing.

In March 2014, in preparation for our 30-day trip to the Southwest, I tried to clean the radiator of debris by blowing compressed air through from the back (fan side). I decided that the cleaning method was not working very well so I chose to remove the radiator from the car so I could clean it more completely and straighten some fins that I bent trying to use the compressed air.

With the radiator out of the car it was obvious that there was debris stuck in the fins. The best way I found to remove it was to lay the radiator flat on the driveway, lift it about 3 inches and slam it down on the concrete. Each time I did this, I got a debris pattern of fine, grit like fine sand, that matched the circles of the two fans. I repeated the mechanical shock cleaning many times until the grit was mostly gone. I straightened the fins and reinstalled the radiator.

With the cleaned, original, 150,000 mile radiator, the cooling system, is working fine. I had no problems in the Southwest or on any trip since.

I believe that any cooling system analysis needs to address the air flow through the radiator. Based on the conditions of my radiator, I doubt that even an additional fan or higher flow fans would have helped.

Thinking back, based on the time it took to clean the radiator, it might have been better to just install a replacement radiator. At the time, I was interested in seeing if I could "solve the problem". On other ZR-1's, I have installed both the DeWitts and the Ron Davis radiators.

Jim

Hi Jim--HIL KING had the same issue at about 40k miles or so. Had the radiator removed and it was about 40% blocked with debris (you probably have a photo or two of it in your archives; I believe they were polaroids). Used a low pressure water hose to clean it. Put a 1/4" mesh debris screen on it (and also on WARP TEN). --Bob

[Racinfan83]

This was mine when Marc took it out to clean it...

http://i72.photobucket.com/albums/i178/Racinfan83/Erics%20ZR-1%20Vette/20130923_121026.jpg

Debris screen I made out of a $2.50 aluminum Gutter screen from Lowes...

http://i72.photobucket.com/albums/i178/Racinfan83/Erics%20ZR-1%20Vette/2013-05-09172835.jpg

My car would almost peg the gauge sitting at idle before I had Marc clean the radiator out and put his chip in that turns both fans on at 200 degrees. Now it hardly gets to 200. The only problem I still have related to that - is that the A/C blows hot at idle and really messes with idle speed when compressor kicks on. I had it switched to R-134 by a Chevy dealer - could they have missed something they needed to change as well??

[Dynomite]

Just installed ANOTHER Ron Davis Radiator. I did some initial testing during the coolant refilling and topping off of coolant after a heating cycle. Idling in the shade (96 deg F ambient) with AC Full ON. Got the same results in 100 deg F ambient.

What happened was very very interesting. My fans come ON at 205 deg F and off at 200 deg F with Marc Haibeck Chip. The coolant temperature idling rose to 205 deg F and the Fans came on. The coolant temperature immediately dropped to 198 deg F as the Fans came OFF. The idling Coolant temperature then rose again until the fans came on and back and forth. At the rate the coolant temperature dropped with fans on assures me that there is considerable reserve cooling capacity with the fans on.

Pay attention to Jim Voters on how to clean a radiator in Post #7 above.......I cleaned my stock radiator (I thought) but did not remove it. It was not completely clean so I would say as Jim has proven you have to remove the stock radiator if you want it cleaned. And as Racinfan83 did below.

It appears that if you remove the stock radiator and COMPLETELY clean it as Jim suggests and also clean the AC Condenser and Oil Cooler at the same time, you can run the ZR1 in HOT climates in stop and go driving. Having said that, it sure is nice to have a Ron Davis Radiator which apparently has considerable reserve capability for cooling the ZR1 in HOT climates.

This was mine when Marc took it out to clean it...

http://i72.photobucket.com/albums/i178/Racinfan83/Erics%20ZR-1%20Vette/20130923_121026.jpg

Debris screen I made out of a $2.50 aluminum Gutter screen from Lowes...

http://i72.photobucket.com/albums/i178/Racinfan83/Erics%20ZR-1%20Vette/2013-05-09172835.jpg

My car would almost peg the gauge sitting at idle before I had Marc clean the radiator out and put his chip in that turns both fans on at 200 degrees. Now it hardly gets to 200. The only problem I still have related to that - is that the A/C blows hot at idle and really messes with idle speed when compressor kicks on. I had it switched to R-134 by a Chevy dealer - could they have missed something they needed to change as well??

[edram454]

I am looking to switch out my stock radiator as preventive maintenance and replace it with a champion 3 core all aluminum unit. I dont see the reason to spend 600 and up for a radiator when champion offers there 3 core at 225.00. A little trimming is required for the radiator to fit since it is squared off and it then slides in. I will also be replacing my thermostat with a stant and will drill 3 little 1/8 inch holes in it as suggested to me by Jerry Downey. I live in a very hot climate most of the year and cooling is a very serious concern. I have a chip to turn fans on but I also have manual overrides to both fans so I just always keep them on. My car seldom goes over 205 degrees in the day time and I usually never run the ac. I just turn it on for about 5 minutes and turn it off.

Nothing wrong with my ac since it is all new and converted to r134 but I would rather hear my car and make sure all is well with it. I think with a new 3 core aluminum unit, stant thermostat and my manual fans this car will do alright down here in miami. It is already mid nineties and very humid so most cars start to struggle down here at this time.

ed ramos #3028

[GOLDCYLON]

Good timing Cliff. On the way home the outside temp on I-17 was 122 on the outside thermometer in Phoenix Yesterday. :cheers:

[Dynomite]

Good timing Cliff. On the way home the outside temp on I-17 was 122 on the outside thermometer in Phoenix Yesterday. :cheers:

It might get up to 115 deg here in Central Valley in July/Aug....I will do another test then. If ambient is 122 deg F.....ALL bets are off on a Stock Radiator keeping the LT5 cool in stop and go traffic with AC ON. Even with AC OFF it might be wishfull thinking with a stock radiator.

I think the Ron Davis would handle it given how fast the Coolant Temperatures dropped when the fans came on at 205 deg F Coolant Temperatures during an idling test with AC FULL On in 100 deg F ambient.

I will watch for a HOT day in the Central Valley or take the ZR1 down to ZFdoc in Cave Creek, AZ on a HOT day to pick up my rebuilt ZF S6-40 Transmisison :D

[Vetman]

My stock 1990 #2441 with 70,000 ran was running about 195 when on the road. Stop and go about 220 and with AC on looks like about 240. Marc programmed my chip and with AC on in traffic never over 200. Dave McClellan has stated that the stock radiator has more capacity than needed for the LT-5. I am convinced. Just clean up your radiator and get Marc's chip!

[Dynomite]

My stock 1990 #2441 with 70,000 ran was running about 195 when on the road. Stop and go about 220 and with AC on looks like about 240. Marc programmed my chip and with AC on in traffic never over 200. Dave McClellan has stated that the stock radiator has more capacity than needed for the LT-5. I am convinced. Just clean up your radiator and get Marc's chip!

What was the ambient temperature when you were running observing Coolant Temperatures?

Concur on cleaning the Stock Radiator but as Jim suggests the only way to really clean the Stock Radiator is to remove it for cleaning. I did not remove my Stock Radiator and thought it was clean but it was NOT completely Clean resulting in higher Coolant Temperatures.

The beauty of a Ron Davis Radiator (or any one of several other Aftermarket Aluminum Radiators) is that you do not have to turn AC off or concern yourself with relatively high Coolant Temperatures on HOT days in Stop and Go Traffic. I am talking about Coolant Temperatures over 230 deg F which I think is normal for a Stock Radiator with AC ON idling on HOT (over 100 deg F) days. I am running more than 25 deg F Cooler with Ron Davis Radiator in traffic on HOT days.

Using Ron Davis Radiators......100 deg ambient temperature (no wind). Both a 1990 and a 1991 ZR1 had the same identical Results (the 1991 with Full Offroad Exhaust).

Cruising at 60 mph in 5th with AC Full On (fans at speed 10) Coolant Temperature stabilized at 197 deg F.

Idling (for at least 15 minutes) with AC Full ON (fans at speed 10) Coolant Temperature stabilized at 213 deg F. This Coolant Temperature dropped to 208 deg F with AC Off.

[Billy Mild]

Anyone using water wetter?

[Dynomite]

Anyone using water wetter?

Hib Halverson for one uses Red Line water wetter........

Use of Red Line Water Wetter (http://www.zr1.net/forum/showthread.php?p=165359#post165359")

[GOLDCYLON]

Good timing Cliff. On the way home the outside temp on I-17 was 122 on the outside thermometer in Phoenix Yesterday. :cheers:



And 123 yesterday. But the proof is in the pudding. No need to heat up the tires boyz.

http://i1120.photobucket.com/albums/l498/goldcylon/123_zpsdsykduoh.jpg (http://s1120.photobucket.com/user/goldcylon/media/123_zpsdsykduoh.jpg.html)

[Dynomite]

What does that mean "no need to heat up the tires"?
What I want to see is actual Coolant Temperatures idling for 10 minutes with AC Full ON.....

Push and hold two buttons each side of Fan Speed Control until you get -00......
then push right Fan Button until you get to - 16.....
then push Fan Speed Control Button......
Show me the actually coolant temperature with Fans Full On (10) idling for 10 minutes in 100 deg F or greater deg F......
That would be interesting in 123 deg F ambient with Spal Fans and Dewitt Radiator :p

Do It......I Dare You :D

I did it yesterday in 100 deg F on Black Pavement in the sun.....idling for 15 minutes after a 20 mile cruise in both a 1990 and 1991 ZR1.
Got coolant temperature of 213 deg F stabilized after 15 minutes idling with AC FUll On (fans at speed 10). This with Ron Davis Radiator and Stock Fans with Haibeck Chip.
That is hard to beat ;)

And 123 yesterday. But the proof is in the pudding. No need to heat up the tires boyz.

http://i1120.photobucket.com/albums/l498/goldcylon/123_zpsdsykduoh.jpg (http://s1120.photobucket.com/user/goldcylon/media/123_zpsdsykduoh.jpg.html)

[GOLDCYLON]

What does that mean "no need to heat up the tires"?
What I want to see is actual Coolant Temperatures idling for 10 minutes with AC Full ON.....

Push and hold two buttons each side of Fan Speed Control until you get 00:00......
then push right Fan Button until you get to 16.....
then push Fan Speed Control Button......
Show me the actually coolant temperature with Fans Full On (10) idling for 10 minutes......
That would be interesting in 123 deg F ambient with Spal Fans and Dewitt Radiator :p

Do It......I Dare You :D

Car would prob melt like the tires lol. Keep in mind that outside temp is nebulus as the sensor is just below the radiator but it is a TRUE indication of the heat coming up (radiating) from the Freeway tarmac in Phoenix. The acutal temp is really 116. However that is the heat our bottom air feeding Zs are truely subjected too. The hotest I ever saw that outside sensor reading is 131. Also why GM had a proving grounds out here :cheers:

[RussMcB]

Anyone using water wetter?Yes, especially in race cars. Not only does it assist in heat transfer, it has some additives that help the cooling system. The additives are often in anti-freeze, but most racing organizations don't want slippery anti-freeze on race tracks.

I've never heard a negative thing said about Water Wetter.

Valvoline Super Coolant (made by Zerex) is another similar product with a good reputation.

[Dynomite]

Car would prob melt like the tires lol. Keep in mind that outside temp is nebulus as the sensor is just below the radiator but it is a TRUE indication of the heat coming up (radiating) from the Freeway tarmac in Phoenix. The acutal temp is really 116. However that is the heat our bottom air feeding Zs are truely subjected too. The hotest I ever saw that outside sensor reading is 131. Also why GM had a proving grounds out here :cheers:

SO.......I would really like to see you idle for 15 minutes after a 20 mile cruise (engine at full temperatures) with AC Full On and a digital Readout of Coolant Temperature........

Or.....better yet....

to compare you Spal and Dewitt set up to my Ron Davis Set Up....catch the temperature at just above 100 deg F in the evening and run that test idling for 15 minutes.......I got 101 deg C on the Digital Readout.

[Hib Halverson]

Hib Halverson for one uses Red Line water wetter........

Use of Red Line Water Wetter (http://www.zr1.net/forum/showthread.php?p=165359#post165359&quot;)

These days, I use either of two coolant additives, either Gibbs Driven CSP or Red Line Water Wetter.

At one time, I advocated solely Red Line's product but Red Line Oil has been sold twice–first, in 8/13, to Spectrum Corporation which was part of Dominus Capital's holdings and, then, secondly, in 6/14 when Dominus Capital sold Spectrum to Conoco/Phillips.

Since these sales, Red Line has already altered the formulation of Complete Fuel System Cleaner. It once treated 120 gallons of gas. Now it treats only 20 gallons, but the price is unchanged. Clearly, this is a move by Red Line's current management to increase profit on that product and do it in a way which customers will not realize unless they read the small print on the container. The reason I'm testing Driven CSP is in case Red Line decides to dilute the formulation of Water Wetter.

In fact, CSP may be a better product than the current Water Wetter because, while RLWW and CSP have a similar effect on cooling systems, CSP's formulation is said by Joe Gibbs Racing to more tolerant of hard water than the "leading brand" which, right now, is Red Line Water Wetter. That feature of the CSP formulation makes more tolerant of mixing with tap water in places where water has a high mineral content.

My current coolant mix in my LT5 is 100% distilled water with 1.5 bottles of RLWW. The next time I change the coolant, I'm going to swtich to 100% tap water and a bottle of Gibbs CSP.

As for the rest of my '95'd cooling configuration, I am still using the same Fluidyne radiator I installed in 1998 during the period of time that the late Jim Van Dorn and I developed that radiator for Fluidyne. The nice thing about the Fluidyne is that it was truly a "drop-in" fit. You simply removed the stock radiator and put the Fludyne in its place. No other changes were required. The Fluidyne's tube count and configuration along with the way the radiator was manufactured offered a noticable improvement in cooling performance. Unfortunatley, the Fluidyne radiator for late C4s was not a market success and is no longer made, but it proved to be a very durable product, having lasted 17 years in service in my 1995.

I also have a 170° thermostat, a calibration with revised fan-on strategy and a front air dam which is in good condition. Periodically, I pull off the top of the cooling stack to clean out any trash between the hvac, the oil cooler and the radiator.

As some may know, Jim Van Dorn died unexpectedly on 14 May at age 59.
In a strange irony, tomorrow (20 June 2015) Jim's three children are having a celebration of their Dad's life. They are holding this event in the Palm Desert, California area where Jim once lived.

The Van Dorn kids have asked me to come speak at this memorial. To honor Jim's memory, I'm going to drive Barney, my '95, on the five hour trip from where I live in Goleta to Indio where the celebration will be held.

The weather down there this weekend will be unseasonably hot–even for summertime in the California low desert. The high temperature on Saturday will be 115°F. That will be a great test of radiator that Jim and I developed 17 years ago and the cooling system configuration I've used all these years.

[Karl]

I will add my cooling experiences. Hopefully you don't mind.

I run Pete's under drive lightweight aluminum water pump pulley and so far with the Fluidyne radiator the cooling is under control.

A couple of weeks ago I was driving about 85 on a hot humid day, somewhere in the lower 90's and the coolant temp on the highway got up to ~208 and when I got off the highway it came down to ~200 and held there.

Today I sat in traffic and its ~81 degrees and humid and the temp did not exceed 200 until traffic began to move ~65 mph and it crept up to ~205.

*edit* Both above are with the a/c on full blast.

I am running distilled water and green antifreeze. Somewhere 60/40 distilled water/antifreeze.

[Dynomite]

I will add my cooling experiences. Hopefully you don't mind. The more input/examples the better....and thanks :handshak:

I run Pete's under drive lightweight aluminum water pump pulley and so far with the Fluidyne radiator the cooling is under control.

A couple of weeks ago I was driving about 85 on a hot humid day, somewhere in the lower 90's and the coolant temp on the highway got up to ~208 and when I got off the highway it came down to ~200 and held there.

Today I sat in traffic and its ~81 degrees and humid and the temp did not exceed 200 until traffic began to move ~65 mph and it crept up to ~205.

*edit* Both above are with the a/c on full blast.

I am running distilled water and green antifreeze. Somewhere 60/40 distilled water/antifreeze.


Here in Central Valley CA early afternoon in foot hills it was 105 deg F. With a Ron Davis cruising at a mild 55 mph with AC Full ON the Coolant temperatures were around 200 deg F. The Fans come ON at 205 deg F and OFF at 200 deg F.
Basically the Coolant Temperatures stayed in the range of Fan Operation.

[rkreigh]

I run the ron davis in the lpe and find that the factory fans aren't strong enough for the thicker cooling stack

I'm going to clean my rad out, marc serviced it a few years back and the old gal his 93k on it with the last 8 hours of driving up and down 211 in the mountains skyline drive and the back roads around the mountains keep you off 81 south and the drive is treat

I'd love to do skyline drive down to the dragon camping along the way

it would be a hoot.

[Dynomite]

I run the ron davis in the lpe and find that the factory fans aren't strong enough for the thicker cooling stack

I'm going to clean my rad out

My experience is a bit different regarding 1990 Stock/Factory Cooling Fans and A Ron Davis Radiator........

I checked my fans, the fans blew a lot of air (like holding your hand out the window at 20-30 mph) when they came on pulling that air through the stack (AC Condenser, Oil Cooler, Ron Davis Radiator). The Fans came on intermittently almost immediately after starting the engine (with AC Full ON and AC Fan Speed 10). The Stack consists of the AC Condenser in front of the Oil Cooler and the Ron Davis Radiator the last in the stack (to the rear). I will check the Coolant Fans Air Flow through the Stack consisting of the Ron Davis Radiator. If I can measure the Air Flow even approximately one can use that Air Flow Rate to determine the condition of a Stock Radiator in Comparison regarding trash that might be restricting Air Flow. Or compare a Ron Davis to a Fluidyne to a Dewitts to a Cleaned Stock Radiator in regards to restrictiveness of Air Flow.

I will probably use the credit card swing test comparing the Stock Cooling Fans Air Flow to the Air Flow at various speeds out the window.......it is a start a step better than me just telling you what the Air Flow Feels Like :D

Or this Anemometer Ebay Anemometer (http://www.ebay.com/itm/Digital-Anemometer-Wind-Speed-Meter-Air-Flow-Meter-Tester-Backlight-MS6252A-US-/361122182876?pt=LH_DefaultDomain_0&hash=item54148f36dc)

How much air or how restrictive the Ron Davis Radiator?......all I can say is the Fans blew air at what seemed to be the same rate as before
I installed the Ron Davis Radiator (actually a bit more air since that stock radiator was not as clean as I thought it was).

Also checked the bottom of the AC Condenser and Bottom of the Oil Cooler. The bottom of the AC Condenser which is most restrictive to air flow has approximately a clear 1 inch space to the bottom of the Radiator Housing. The air space between the Oil Cooler and bottom of the housing is approximately 1/2 inch.

Air can enter the 1 inch gap (or a bit greater) between the Oil Cooler and Ron Davis Radiators coming under the Condenser and Oil Cooler or up between the Condenser and Oil Cooler (approximately 1/2 inch gap) and through the Oil Cooler, or up between the Oil Cooler and Ron Davis Radiator (approximately 1 inch gap).....then up and through the Ron Davis Radiator.

The AC Condenser and Oil Cooler have a rather narrow gap between them (estimate 1/2 inch).

I run Pete's under drive lightweight aluminum water pump pulley and so far with the Fluidyne radiator the cooling is under control.

I have a Fluidyne Radiator in 1990 #3032 and Ron Davis Radiators in the other ZR1s.

[-=Jeff=-]

So I am reading of the main benefits of the swap.. what are the downsides of a bigger radiator (excluding: fit, non-stock/vs stock)

Basically, in a perfect scenario, I pull the OEM swap in (brand x)*.. get it burped etc..

what are the negatives?

Brand x could be anything, Ron Davis, Champion, DeWitts, Fluidyne What ever

[Dynomite]

Fit is usually not an issue.
Negatives are cost and installation albiet cleaning a stock radiator is as labor intensive as installing NEW.

[-=Jeff=-]

Fit is usually not an issue.
Negatives are cost and installation albiet cleaning a stock radiator is as labor intensive as installing NEW.

Nothing else?

longer to reach operating temp? nothing out side the norm of a mod..cost, install, etc)

[Dynomite]

Same time to reach operating temperature (thermostat has not opened to radiator).

No Mods other than........ Shave 1/2 inch inside fan baffles for Ron Davis.

Install of New Radiator identical to re-installation of stock radiator after cleaning.

[edram454]

When I send out my car for engine refinishing in August I will be installing a champion 3 core aluminum. When I had my supercharged c5 I swapped in a Mishimoto 3 core radiator and that thing worked great. It looked great and after a little trimming it fit great. My car always ran cool after that swap. that radiator cost me 200.00. Mishimoto is a japanese maker of auto parts used alot by drifter car owners. I know Ron Davis and DeWitts are top of the line quality but they area also expensive. I will take my chances with the champion unit and report how it performs.

ed ramos #3028

[Hib Halverson]

Some results of my cooling test last Saturday in the Indio California area.

Outside air temp was 110-112°F
A/C on all the time. Highest coolant temp I saw when idling or driving in traffic was 208°
Once I entered Interstate 10, cruising at 75-80 in sixth, A/C on the ECT went down to 192°.
As the outside air temp, dropped below 100°, the ECT began to drop as well.

I have a Fluidyne radiator, a nine-tube Fluidyne oil cooler and use straight water for coolant.

[-=Jeff=-]

I have a champion 3 core sitting in the garage. I might install it this winter

[Dynomite]

Some results of my cooling test last Saturday in the Indio California area.

Outside air temp was 110-112°F
A/C on all the time. Highest coolant temp I saw when idling or driving in traffic was 208°
Once I entered Interstate 10, cruising at 75-80 in sixth, A/C on the ECT went down to 192°.
As the outside air temp, dropped below 100°, the ECT began to drop as well.

I have a Fluidyne radiator, a nine-tube Fluidyne oil cooler and use straight water for coolant.

Good stuff there Hib :thumbsup:

That is within 5 deg F of my readings with Ron Davis but then again you are 10 deg Hotter Ambient....and several other differences I am sure ;)

But very close in Coolant Performance....Oh.....I did not say it but I am running a mix of distilled water and green antifreeze which I think your water wetter and straight water will prolly get you a bit cooler :handshak:

I have a Fluidyne (not sure exactly which one) that was in a 1990 ZR1. I removed that Fluidyne and installed a Ron Davis moving that Fluidyne over to another 1990 replacing its stock radiator.

It gets complicated :D

You want to have some fun.......see LT5 Cooling for Autocross (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3649154-autocross-zr1-3.html#post1589904217)

I have a champion 3 core sitting in the garage. I might install it this winter
Why wait....do it now :D
I will tell you about my new fool proof Coolant Re-fill technique that assures NO air within the Coolant System when you are done Re-filling with Coolant ;)

[FU]

I have a champion 3 core sitting in the garage. I might install it this winter

Install the Champion radiator. They work great !

[-=Jeff=-]

Install the Champion radiator. They work great !

Yeah I need to start a list for inter already.. LOL

not doing anything unless I NEED to this summer

[Hib Halverson]

Good stuff there Hib :thumbsup:

That is within 5 deg F of my readings with Ron Davis but then again you are 10 deg Hotter Ambient....and several other differences I am sure ;)

But very close in Coolant Performance....Oh.....I did not say it but I am running a mix of distilled water and green antifreeze which I think your water wetter and straight water will prolly get you a bit cooler :handshak:

I have a Fluidyne (not sure exactly which one) that was in a 1990 ZR1. I removed that Fluidyne and installed a Ron Davis moving that Fluidyne over to another 1990 replacing its stock radiator.

It gets complicated :D



There was only one Fluidyne which fit all late C4s (i.e.: anything with the tilted back radiator) and that's the one I developed with Jim Van Dorn's help.

Actually, we did all the hot weather testing in Palm Desert working out of Jim's old shop. We did that in September and the OAT then was actually even hotter than it was in Indio last Saturday–115° stick in my mind, but I'll have to confirm that. We tested on CA SR74 going uphill at about 8/10s. You can find SR74 on Google Maps by looking for the junction between US 111 and CA SR74. Once that road get curvy on the west side of Palm Desert is where we tested. The locals call it "7-level hill". Running the engine that hard, believe it or not, had lower ECT because the RPMs were up in the area where the system actually cools better, however, our sustained rpm was not so high that the coolant bypass became a problem.

I made a lot of posts to the ZR-1 Net back then explaining the Fludiyne design and how we tested it. Back then, our target competitor was the Ron Davis. I don't know what Davis sells now, but back then his radiator for late C4s was not a bolt-in and required fabrication work to fit.

The Fluidyne not only cooled better than what Ron Davis was selling at the time, but it dropped right in the stock cooling stack.

I'll look around in my several 1TB hard drives to see if I have any of that old stuff.

Also, if there's anyone here who knows how to research old ZR1Net posts from the 1998-1999 period, you may find my discussions of the Fluidyne.

[XfireZ51]

Hib,

I installed what I believe would be the Flyidyne you guys developed. It does "drop in". We haven't had incredibly hot temps here in Chicagoland, but it does the job w typical coolant temps in the 85-88C range. Haven't seen anything over 95C. And have not yet tried A/C. Just no need to so far. The biggest issue I had was getting the motor up to operating temps w ambient air at 0-10C. Had it out last winter on a dry day and it would not go above 50C.

[Dynomite]

The Fluidyne All Aluminum Radiator is now in the Last 1990 sold to public #3032. It dropped right in with no issues. I wanted to keep this as stock as possible without having to shave the Fan Baffles for a Ron Davis Radiator Fit.

1990 ZR-1 (Number 3032 - The Last 1990 Sold)
TB Coolant Blocked at IH
Fluidyne Radiator
RC Injectors
Haibeck Chip
Billet Aluminum Belt Tensioner Pulley
Billet Aluminum Power Steering Pulley

http://i287.photobucket.com/albums/ll142/dynomite007/90%20ZR1%20sd/425b2c82-572d-406b-83cf-fe1cefe59702.jpg

There was only one Fluidyne which fit all late C4s (i.e.: anything with the tilted back radiator) and that's the one I developed with Jim Van Dorn's help.

Actually, we did all the hot weather testing in Palm Desert working out of Jim's old shop. We did that in September and the OAT then was actually even hotter than it was in Indio last Saturday–115° stick in my mind, but I'll have to confirm that. We tested on CA SR74 going uphill at about 8/10s. You can find SR74 on Google Maps by looking for the junction between US 111 and CA SR74. Once that road get curvy on the west side of Palm Desert is where we tested. The locals call it "7-level hill". Running the engine that hard, believe it or not, had lower ECT because the RPMs were up in the area where the system actually cools better, however, our sustained rpm was not so high that the coolant bypass became a problem.

I made a lot of posts to the ZR-1 Net back then explaining the Fludiyne design and how we tested it. Back then, our target competitor was the Ron Davis. I don't know what Davis sells now, but back then his radiator for late C4s was not a bolt-in and required fabrication work to fit.

The Fluidyne not only cooled better than what Ron Davis was selling at the time, but it dropped right in the stock cooling stack.

I'll look around in my several 1TB hard drives to see if I have any of that old stuff.

Also, if there's anyone here who knows how to research old ZR1Net posts from the 1998-1999 period, you may find my discussions of the Fluidyne.

I am probably the last one to install (Re-Install) a Fluidyne Aluminum Radiator in May 2015. The Fluidyne was like new with very little trash on the front face. I simply removed it from 1990 ZR1 #2067 having SW Offroad Exhaust and intstalled it back into ZR1 #3032 having Stock Exhaust. I did check Fluidyne Radiators (http://www.fluidyne.com/) in May 2015 looking for that Fludyne Aluminum Radiator since it did not have any numbers on it. I could not find a Fluidyne Radiator for a 1990 ZR1 Corvette.

That Fluidyne Aluminum Radiator was a very nice Radiator (a bit thinner than the Ron Davis) and having the Fluidyne All Aluminum Radiator out on the floor I just decided to install it back into a Stock 1990 ZR1 since that Fluidyne required NO Fan Shroud Trimming and it was a Mint Condition ALL Aluminum Radiator. I removed the Fluidyne Aluminum Radiator from ZR1 #2067 for cleaning and identification (which it did not really need any cleaning and it did have the Name Fluidyne but no Numbers).

I did run the Fluidyne Aluminum Radiator in ZR1 #3032 but the ambient temperatures were only in the 70s so not a real test but it seemed to cool just fine.

It appears that Fluidyne Aluminum Radiator I installed in ZR1 #3032 is no longer made or is identical for another application and just not listed for a C4 ZR1 Corvette.

That Fluidyne Aluminum Radiator would definitely be a very nice ZR1 Radiator to replace the ZR1 Stock Radiator
if it were available from Fluidyne Fluidyne Radiators (http://www.fluidyne.com/) :thumbsup: :thumbsup:

[XfireZ51]

After installing the Fluidyne, I actually modified the calibration to RAISE THE fan temps.

[PhillipsLT5]

I bought a fluidyne years ago on Hibs suggestion/review, all good in HOT AZ

[mike100]

My contribution to this topic is that I gave the alternator and 12v system a break by offsetting fan1 and fan2 to turn on at 2 deg different temps so you don't get that massive lcd display dimming inductive load kick on all at once.

[Dynomite]

I bought a fluidyne years ago on Hibs suggestion/review, all good in HOT AZ

I did run the Fluidyne Aluminum Radiator in ZR1 #3032 but the ambient temperatures were only in the 70s so not a real test but it seemed to cool just fine.

It appears that Fluidyne Aluminum Radiator I installed in ZR1 #3032 is no longer made or is identical for another application and just not listed for a C4 ZR1 Corvette.

That Fluidyne Aluminum Radiator would definitely be a very nice ZR1 Radiator to replace the ZR1 Stock Radiator
if it were available from Fluidyne Fluidyne Radiators (http://www.fluidyne.com/) :thumbsup: :thumbsup:

[XfireZ51]

My contribution to this topic is that I gave the alternator and 12v system a break by offsetting fan1 and fan2 to turn on at 2 deg different temps so you don't get that massive lcd display dimming inductive load kick on all at once.

Mine come on at 2 different temps also.

[Hib Halverson]

After a long search of two different computers, I found my original notes written to the management of Fluidyne in September of 1999, after Van Dorn and I finished our hot weather testing of the Fluidyne Radiator

My memory as to the ambient temperature during those few days of testing was not so good. In an earlier post, I said it was 115°. Actually the hottest OAT we observed during testing was 111°.

The memo to Fluidyne has been converted to a .pdf. It's an interesting insight to the kinds of stuff the original Auto Masters and myself were doing 16 years ago. At the end of the memo is all the testing data. Tests #8 and #9 were both done on CA SR74 in the "7-Level Hill" section and were run uphill at near racing speeds, i.e.: about as hard as I could drive given I had to stay on the right side of the road. The distance from my starting point to the top of 7-Level was 4.9-mi. I included a Google Maps screen shot of the course used in testing. All the mountain road testing was done uphill.

The radiator uses for that test is still in my car today. The only difference in my cooling set-up now is I use 100% water and RLWW rather than 75% water and 25% Dex-Cool.

If anyone has any questions, post them and I'll try and answer.

[Billy Mild]

http://www.corvetteforum.com/forums/c4-tech-performance/3635438-upgraded-radiator.html

I saw this post about a upgraded radiator from amazon. It is has more cores and appears to help with cooling.

[RussMcB]

http://www.corvetteforum.com/forums/c4-tech-performance/3635438-upgraded-radiator.html

I saw this post about a upgraded radiator from amazon. It is has more cores and appears to help with cooling.Thanks for sharing. It's good to hear about all options. I read the reviews and they are mixed (with neither high praise or very negative). It appears to have the auto transmission cooler section, which I'd guess would take away from the total cooling ability.

It's probably a good choice for some C4 folks wanting to improve from stock, but I'd think most here would rather spend a bit more and get known high quality.

[Hib Halverson]

http://www.corvetteforum.com/forums/c4-tech-performance/3635438-upgraded-radiator.html

I saw this post about a upgraded radiator from amazon. It is has more cores and appears to help with cooling.

Keep in mind that radiator is not a drop-in fit. If you read the CF post you see that the user had to do some modifications to the cooling stack to get it to fit properly. Also he talks about some difficulty in connecting all the hoses.

That radiator is a universal C4 replacement in that it has the transmission EOC in the right side tank. Obviously, the ZR-1 would not use those connections.

Lastly, Amazon lists the seller at "Auto Dynasty". Try and find them on the web. Good luck. If you want to buy that radiator make sure you understand the manufacturer's warranty before you enter your credit card number.

[dredgeguy]

I just purchased a DeWitt radiator and a set of new hoses from Jerry's. Looking forward to getting it installed. Last week in 92 degree heat got stuck in traffic and temp was pegged before I noticed it. Almost had a stroke......checked the digital gauge and it was 258! Turned off the A/C, turned on the heater and good luck was with me. Traffic opened up and I got to 70 MPH and it cooled down to 202 in a couple of minutes. Then I went home, cleaned my pants and ordered a the same radiator recommended by fellow Wazoo, SecondChance.

[efnfast]

Charlie, is that 158 suppose to be 258?

[dredgeguy]

10-4 on that, it should have been 258, made the edit correction. Just thinking about it still shakes me up as you can see.

[efnfast]

Minga, I'd have had the hood open, blowing on the engine. That's hot.

[dredgeguy]

Minga, I'd have had the hood open, blowing on the engine. That's hot.

I was afraid it was gonna blow!

[efnfast]

They tell me it's a pretty hearty engine.

[Dynomite]

I just purchased a DeWitt radiator and a set of new hoses from Jerry's. Looking forward to getting it installed. Last week in 92 degree heat got stuck in traffic and temp was pegged before I noticed it. Almost had a stroke......checked the digital gauge and it was 258! Turned off the A/C, turned on the heater and good luck was with me. Traffic opened up and I got to 70 MPH and it cooled down to 202 in a couple of minutes. Then I went home, cleaned my pants and ordered a the same radiator recommended by fellow Wazoo, SecondChance.

Well..........that is the issue......the ZR-1 in traffic even with a clean stock radiator does get HOT.....let us know just how clean your stock (if it is stock) radiator was when you remove it (also .....clean the AC Condenser and Oil Cooler when you are there). That will be interesting.

You do not have to cut or modify the Radiator Housing when you remove the radiator but let the engine sit overnight and remove the Oil Cooler Adapter setting the hoses and adapter off to the side (do not disconnect them from Oil Filter Adapter). That will allow you to lift the Radiator Housing up on the Drivers side followed by lifting (bending the tab a bit) the Radiator Housing on the Passenger side last. Reverse for Installation of the Radiator Housing after New Radiator installed.

It is easiest to separate the Thermostat Housing so you can remove the Bottom Radiator Hose (may take a razor blade to cut hose lengthwise to get it off stock radiator). Remove Thermostat and may want to install new thermostat when you are at it. I remove the two (13mm head) bolts holding the thermostat housing to the frame before I remove the three (13mm heads) thermostat Housing Bolts.

One short bolt holding the thermostat housing to the bracket and one long bolt holding the thermostat housing to the bracket also and holding the thermostat housing halves together with the third long bolt. It is a bit tricky holding the thermostat in place when assembling (use a putty knife). the new or old thermostat making sure the rubber thermostat gasket is not misplaced.

There is a bit of a science to refill with coolant but if water pump is not drained you should be fine when refilling the reservoir in front of the Passenger Side windshield with coolant (slowly as air should bubble back from vent hose at top of radiator). Make sure the two Injector Housing Coolant Manifolds are getting warm within one minute after firing up the engine. Before the radiator pressure rises, turn the engine off several times and add coolant to the Coolant reservoir on passenger side just in front of windshield.

[Billy Mild]

Can a stock clean radiator provide enough cooling for the LT5? It seems that the aftermarket units really help it cool the way it should have from the factory.

[Dynomite]

Can a stock clean radiator provide enough cooling for the LT5? It seems that the aftermarket units really help it cool the way it should have from the factory.

That is the question.....I think NOT (the LT5 will run on the HOT side especially if you have AC ON) idling in traffic at 100 deg F ambient. With AC OFF you will run 5 to 10 deg F Cooler depending on your AC System. Once you get moving say 30 mph I think you can keep Coolant Temperatures in the 220 deg F range or a bit less.

That is my experience with several stock radiators but I can honestly say I have never had a correctly cleaned stock radiator to work with (only thought I did). You have to remove the radiator to clean it properly and also clean the AC Condenser and Oil Cooler with the Radiator Removed as Jim (QB93Z) Describes.

I think Jim (QB93Z) had some luck with a properly cleaned stock radiator on his AZ trip but Jim would have to describe that situation including the temperatures and if he was in traffic.

I have some thinking on Fans (GOLDCYLON has experience with fans) and Thermostats as well as chips to turn fans on at lower temperatures. As I recall the stock fans turn on at Temperatures in the 220 deg or higher range (maybe 228 deg F) which leads me to believe it was expected that the LT5 might run that HOT.

Last week in 92 degree heat got stuck in traffic and temp was pegged before I noticed it. Almost had a stroke......checked the digital gauge and it was 258! Turned off the A/C, turned on the heater and good luck was with me. Traffic opened up and I got to 70 MPH and it cooled down to 202 in a couple of minutes. Then I went home, cleaned my pants and ordered a the same radiator recommended by fellow Wazoo, SecondChance.

I had an experience a couple years ago when my impeller fell off the water pump shaft (water pump shaft spun freely). Who would have thought it :D
Got almost to cross hatched area and I shut it down. Took a while to figure that one out ;)

[QB93Z]

Can a stock clean radiator provide enough cooling for the LT5? It seems that the aftermarket units really help it cool the way it should have from the factory.

Your question has many answers depending on several factors. Is the C4/LT5 modified in any way that would affect power output or normal operation? What type of driving are you doing? Is the exhaust system modified? Do you ever go faster than the speed limit? Do you use the C4/LT5 for off road driving or racing?

I believe that a stock C4/LT5 with a stock radiator and fans that has no debris in the air flow path will operate in the normal temperature range.

If you make any modifications that increase power, you will have to modify the cooling capability to keep up. Or, as a minimum you will have to ensure that the air flow through the radiator is not reduced by debris.

Jim

[Dynomite]

Here in Central Valley CA predicted 107 deg today with 100 deg every day through July 14 (then 109 deg on July 15). Will get lots of Engine Coolant System Testing done using Ron Davis Radiators next couple weeks in what I would call extreme Ambient Temperatures ;)

Got Engine Coolant temperatures up to 220 deg F yesterday in 100 deg ambient racing around (No Traffic) and in traffic (idling in traffic and 100 mph on Test Road) and at higher rpms without paying attention to what I call (conservation of Engine Coolant Temperatures). Engine Coolant Temperatures quickly dropped over 15 deg once I collected myself and this with AC Full On (fan speed 10). The Engine Coolant Temperatures actually dropped a bit just idling in traffic after I was done fooling around :sign10:

You may think 220 deg F is HOT but in a Stock Radiator Fan System, the Radiator Fans would not even come on yet (My Radiator Fans were ON with Haibeck Chip and 180 deg Thermostat) :D

If you are NOT looking at Digital Engine Coolant Temperatures using the HVAC System, the Temperature Gauge needle is a tad under half or at half at Engine Coolant Temperatures around 200 deg F and a tad over half at Engine Coolant Temperatures around 220 deg F. Each Engine Coolant Temperature Gauge will be just a tad different.

HVAC Display Digital Engine Coolant Temperatures in Deg C.......
Push/hold up and down buttons each side of Fan Speed Center Button until you get 00.
Then push Fan Speed Control Button UP to right of Fan Speed Center Button until you get to 16.
Then Push Center Fan Speed Button to Read Engine Coolant Temperatures in Deg C.

Approximate C to F
85 C is 185 F
93 C is 200 F
100 C is 212 F
104 C is 220 F
110 C is 230 F
120 C HOT.....do not operate at 250 deg F (TURN AC OFF).

Also...no one has mentioned except HIB (who uses water coolant and a water wetter only) that if you do not use antifreeze mixture your coolant System could boil over at 212 deg F (a bit higher Engine Coolant Temperatures with a good radiator cap which maintains 15 psi Coolant Pressures). NOT GOOD :cry:

In regard to Loosing Coolant vice Heating Coolant to HOT temperatures. It has been said that as long as you do not loose the Coolant and the Water Pump is NOT Airlocked (like concern for low oil level in oil pan but as long as you have oil pressure) you will NOT destroy the LT5 Engine :cheers:

[Billy Mild]

Your question has many answers depending on several factors. Is the C4/LT5 modified in any way that would affect power output or normal operation? What type of driving are you doing? Is the exhaust system modified? Do you ever go faster than the speed limit? Do you use the C4/LT5 for off road driving or racing?

I believe that a stock C4/LT5 with a stock radiator and fans that has no debris in the air flow path will operate in the normal temperature range.

If you make any modifications that increase power, you will have to modify the cooling capability to keep up. Or, as a minimum you will have to ensure that the air flow through the radiator is not reduced by debris.

Jim

I would think simple mods like airlid mod, or a full exhaust would only help the engine run a bit cooler. I might be wrong though.

[Dynomite]

I would think simple mods like airlid mod, or a full exhaust would only help the engine run a bit cooler. I might be wrong though.

I see no difference in Coolant Temperatures with Stock Exhaust or Full Offroad SW Headers/Exhaust (I have one of each both with Ron Davis Radiators). I think the engine compartment gets hotter with Headers. That theory could result in more HOT Air around the engine and escaping under the car.

Regarding Thermostats........Just as a comparison, I have checked several Stock Thermostats which ALL seem to open at 170 deg F as compared with Marc Haibeck's and Jerry's 180 deg F Thermostats which open AT 180 deg F. Some run 160/165 deg F Thermostats which once the Thermostat is fully open would not make a difference on the stabilized Coolant Temperatures no matter which Thermostat you used (A Cooler Thermostat would make a difference on how fast you get to that stabilized Coolant Temperature). This assumes the Full Open Thermostats are all of the same Coolant Flow Restriction/Flow Rate.

Jerry has the special rubber thermostat gaskets sold separately in case the thermostat gasket gets messed up during installation of thermostat.

I think we need more experiments with Radiator Cooling fan flow rates. We all have experienced trash blocking the radiators and the higher Coolant Temperature Results. We all have also experienced the effects of vehicle cruise speed on Engine Coolant Temperatures as compared to Engine Coolant Temperatures idling in traffic.

[dredgeguy]

23 years of sucking up debris into the stock radiator. Replaced it with a DeWitt, Jerry's hoses and new 180 degree thermostat and should be good for another 23 years.

[FU]

Did you do the 3 1/8 inch holes in the thermostat mod ?

[dredgeguy]

Did you do the 3 1/8 inch holes in the thermostat mod ?

Lots of discussions about it and went back and forth on this issue. Ended up doing a single 1/8 inch hole

[WARP TEN]

Your question has many answers depending on several factors. Is the C4/LT5 modified in any way that would affect power output or normal operation? What type of driving are you doing? Is the exhaust system modified? Do you ever go faster than the speed limit? Do you use the C4/LT5 for off road driving or racing?

I believe that a stock C4/LT5 with a stock radiator and fans that has no debris in the air flow path will operate in the normal temperature range.

If you make any modifications that increase power, you will have to modify the cooling capability to keep up. Or, as a minimum you will have to ensure that the air flow through the radiator is not reduced by debris.

Jim

Certainly true about having a clean radiator, but even with mods I have not had any overheating issues. I have Marc's 510 HP package which includes his chip that modifies cooling so that both fans come on at 205 degrees. When I first bought the car and again when we did the engine, we checked the radiator for debris and found none. In the two years I have had the modifications, including some mighty hot days (not many this year!), I have never seen coolant temperatures in excess of 208 degrees. Early on I added a debris screen just in case. So a clean stock radiator with both fans coming on at 205 seems to provide adequate cooling for mine even for a slightly modified engine. --Bob

[secondchance]

Did you do the 3 1/8 inch holes in the thermostat mod ?

Frank,

I tried 3 1/8" holes 2 years ago. During the winter coolant temp refused to go above 153 degrees F. I was concerned with inability to boil off water build up in oil. Went to one 1/8" hole and recommended the same to Charlie.

[FU]

Frank,

I tried 3 1/8" holes 2 years ago. During the winter coolant temp refused to go above 153 degrees F. I was concerned with inability to boil off water build up in oil. Went to one 1/8" hole and recommended the same to Charlie.

Interesting , 153 degrees F is no good for a winter driver. What degree thermostat did you use to get up to 153 f ?

[Dynomite]

Frank,

I tried 3 1/8" holes 2 years ago. During the winter coolant temp refused to go above 153 degrees F. I was concerned with inability to boil off water build up in oil. Went to one 1/8" hole and recommended the same to Charlie.

A 1/8 inch hole in the thermostat flange has an area of .0123 square inches compared to an open (or partially open) thermostat (1/4 inch open and say 1.5 inch diameter) of 1.17 square inches.

I am not sure what .0123 square inches adds to the flow rate of an open thermostat? (maybe an increase of 1.18-1.17/1.17 or .85% (less than 1%)

I am also not sure what contribution a .0123 square inch hole creates in terms of flow rate through the radiator when the thermostat is otherwise closed. Or .0369 square inches with three 1/8 inch holes in the thermostat flange.

[secondchance]

Interesting , 153 degrees F is no good for a winter driver. What degree thermostat did you use to get up to 153 f ?
http://i658.photobucket.com/albums/uu303/byongyun/IMG_0800_zps2gqckmjk.jpg (http://s658.photobucket.com/user/byongyun/media/IMG_0800_zps2gqckmjk.jpg.html)
http://i658.photobucket.com/albums/uu303/byongyun/IMG_0801_zpswe61tfob.jpg (http://s658.photobucket.com/user/byongyun/media/IMG_0801_zpswe61tfob.jpg.html)

[FU]

I see 4 of 1/8" holes. What degree theromstat 180f or a stock 195f ?


Thanks for posting a picture of the thermostat.

[secondchance]

I see 4 of 1/8" holes. What degree theromstat 180f or a stock 195f ?


Thanks for posting a picture of the thermostat.

When I dug up the thermostat I realized I had drilled 4 holes and not 3. I believe this is a 180 degree stat.

[dredgeguy]

Greetings from Lagos, Nigeria.....1 day here and only 9 days left but who is counting. I put in a new 180 Stant in mine as suggested by Marc

[Dynomite]

When I dug up the thermostat I realized I had drilled 4 holes and not 3. I believe this is a 180 degree stat.

So...you always have a bit of flow through the radiator......... say four 1/8 inch holes or .0123 square inch additional opening total. It is amazing that the heater (hot side at the thermostat) is only a 1/4 inch diameter port or about .049 square inches total port area. That is about 4 times what you have with the 1/8 inch holes if you turn your heater on full blast.

The bit of flow you have all the time will run the coolant just a tad cooler so the thermostat will open just a bit later. Then as the thermostat approaches fully open the total flow is just a bit more adding in the .0123 square inches with the 1/8 inch holes (.0123 + 1.17 =1.18 square inches).

I am not seeing exactly what the benefit of the 1/8 inch holes gives you given the total flow area of an open thermostat may be over 1.17 square inches and with your four 1/8 inch holes now 1.18 square inches ;)

I can see the thermostat opening a bit more smoothly having the 1/8 inch holes and not opening and closing as rather cold coolant is mixing with hot coolant as the thermostat initially starts to open :thumbsup:

[secondchance]

Cliff,

I understand your calculation and logic. Interestingly, when stock (with Marc's chip), 6th gear cruise (say 70-75) on 80-85 degree day (it's been awhile...) coolant temp would stabilize around 211-213. In 5th gear it would drop to 203-205 probably due to increased coolant flow. With one 1/8" hole coolant temp would maintain, if I remember correct, around 197-198 regardless of 5th or 6th gear - just my experience.
When I dropped in my 380 coolant temp went up a bit across the board. Also, after two blown OEM radiators I opted for non-plastic tank radiator and while at it figured I would try dual core/extra fin area option.

[RICKYRJ1]

Greetings from Lagos, Nigeria.....1 day here and only 9 days left but who is counting. I put in a new 180 Stant in mine as suggested by Marc

Hey Charlie, I just got a email from Nigeria stating I won the nigerian lottery and to send money in good faith so I can collect the winnings, also said they are in love with me but need me to send them money so they can come visit me and another will buy my cay sight unseen and pay whatever I want for it just send them the balance of their over payment :dancing lol. you could have brought your Z with you to really test out the new radiator be safe brother :cheers:

[Dynomite]

Cliff,

I understand your calculation and logic. Interestingly, when stock (with Marc's chip), 6th gear cruise (say 70-75) on 80-85 degree day (it's been awhile...) coolant temp would stabilize around 211-213. In 5th gear it would drop to 203-205 probably due to increased coolant flow. With one 1/8" hole coolant temp would maintain, if I remember correct, around 197-198 regardless of 5th or 6th gear - just my experience.
When I dropped in my 380 coolant temp went up a bit across the board. Also, after two blown OEM radiators I opted for non-plastic tank radiator and while at it figured I would try dual core/extra fin area option.


Good Information.......thanks :thumbsup:
Blown Radiators is not good.....kinda like the time my new water pump impeller became disconnected from the water pump shaft. :rolleyes:

What you find cruising in 6th versus 5th is what I found also which I attributed to higher Coolant Flow Rates in 5th gear as you suggested.

Also your stock radiator (with Marc's chip) coolant temperatures are a bit high (203 to 205 deg F) for an 85 deg F day but NORMAL for a Stock Radiator.

Basically your Coolant Temperature was in the range of your Cooling Fan Operational Limits set by Marc's Chip (ON 205 deg F and OFF 200 Deg F). That is about what I am getting with my Ron Davis on a 90 deg F day. The Coolant temperature stays around 190 deg F and rise to Coolant Termperature Fan Operational Limits when in traffic on a 80 to 90 deg F Day. A 100 deg F + day is a bit hotter Coolant Temperatures ;)

ALL with 180 deg F Thermostat and CLEAN Radiator/Oil Cooler/AC Condenser.

[dredgeguy]

Hey Charlie, I just got a email from Nigeria stating I won the nigerian lottery and to send money in good faith so I can collect the winnings, also said they are in love with me but need me to send them money so they can come visit me and another will buy my cay sight unseen and pay whatever I want for it just send them the balance of their over payment :dancing lol. you could have brought your Z with you to really test out the new radiator be safe brother :cheers:
Ricky, that's why I am here....to collect my winnings. You mean it is not True?:mad:
You should see the roads here, no way could a Z drive here, you need lots of ground clearance. Not much of a test for a radiator, only mid 80's.no humidity and a nice breeze.

[5ABI VT]

Sooo.. which rad do you guys recommend? Im debating on pulling mine for cleaning and a lower temp tstat but an upgrade is in my thoughts.

[RussMcB]

Sooo.. which rad do you guys recommend? Im debating on pulling mine for cleaning and a lower temp tstat but an upgrade is in my thoughts.I'm in the same situation (after very high temps while doing laps at race tracks) and after two discussions with Marc I've decided to clean my current rad first to see if that helps (and try to keep the RPMs down next time at the track). If I still think I need a better rad, and I have plenty of $$$ in the checking account, I'll go with a Dewitts. I do think there are several other very good choices, too, like Ron Davis. If saving money is important, Ron Davis offers a generic Chevy NASCAR model that will work with some mods.

Those are my conclusions after discussions and searching. No real world experience.

[GOLDCYLON]

I suggest Dewitt's and add the SPAL fans. Install is easy and you will gain a little more clearance as the back of the radiator shroud is removed and the SPALs mate to the back side of the front Rad shroud

[dredgeguy]

After seeing the debris in my stock 92, cleaning was out. Would have to send it out and then you still have a 23 year old radiator with plastic sections. Looked at options and costs and went with a DeWitts, a new 180 degree Stant and new hoses from Jerry's.

[lbszr]

My stock radiator would climb at the racetrack, caught it at 250 or so and had to short shift on a 85 degree day.

Today in bowling green track, 30 minute sessions, 95 degrees, it stops at 212, but I did see 216 max. DeWitt, also a big mouth. Had the big mouth on the stock rad, but wasn't enough. I also have manual switch to turn the fans on, I leave it on all the time during track use and it makes a difference.

Oil temp stays steady at 250. Hair below the caution bars.

I think the radiators all mentioned are plenty good.

[5ABI VT]

Just curious if there are any write ups for the install ? In debating on pulling the rad out and cleaning it out before a runway event I signed up for in a few weeks

[-=Jeff=-]

There is a write up on corvette forum that should cover most of the job

[RussMcB]

I'm in the middle, early stages of an R&R. I've removed the stock radiator. It was a bit more difficult than expected. There are three 7mm screws on each side connecting the upper shroud to lower - very hard to access. When I put it back together I'll reverse them and install from the inside for easier access (I read that suggestion in other discussions).

Not surprisingly, there was a lot of dirt and junk in there. I could probably clean and reinstall the stock radiator, but I'd rather not do this job again, so I'm ordering a Dewitts.

As with most of these projects, it's growing. I ordered a set of hoses and a t-stat from Jerry's Gaskets, a "Big Mouth" air dam*, and I'll be adding a screen to help keep out leaves and junk.

To answer your question, I do think you could do the job in a day or weekend (or two nights). If it has never been out and cleaned, I'd think it will be very worthwhile before your track event.

* http://www.c4orcecorvette.com/

[5ABI VT]

Just saw the write up and its a good one :cheers: . My concern is the oil cooler. Does that have any effect on the re/re procedure? More than likely Ill be doing an upgraded rad in the near future but Im sure this one will be full of crud. 21 years old and possibly never out. A few weeks ago with the ac on and parked I noticed the temps did seem to rise quite a bit. I never sit in traffic but when moving they came down pretty fast.

[RussMcB]

The oil cooler stays in place (but you will need to disconnect the lines - just one bolt).

With the radiator out you can blow out the oil cooler's and A/C fins.

It's encouraging that your temps come down pretty fast when the car is moving.

When you go to the race, keep in mind that the coolant in the water pump begins to cavitate at high RPMs, so you can short shift to avoid that if needed.

[5ABI VT]

The oil cooler stays in place (but you will need to disconnect the lines - just one bolt).

With the radiator out you can blow out the oil cooler's and A/C fins.

It's encouraging that your temps come down pretty fast when the car is moving.

When you go to the race, keep in mind that the coolant in the water pump begins to cavitate at high RPMs, so you can short shift to avoid that if needed.


I need to do some searching on cleaning out the oil cooler as well I recall people saying they were full of sludge etc. the event is only a half mile so it's not very long at all. I'm wot through 3-4 gears all the time ;) and never see any temp issues . I usually watch the oil temps and they're never too high. I think for a wot run oil will have a big impact on cooling as well and with the capacity and oiling on the LT5 it does an excellent job.

As for water pumps I definitely will be moving to electric water pumps I need to do more research on available setups but after having one in my last 388 lt4 build that I used at high rpm all the time for extended periods .. Worked wonderfully (with a stock rad).

[Fully Vetted]

If you don't mind I'm curious what you find is available on the electric wp's. Please repost.

[Dynomite]

The oil cooler stays in place (but you will need to disconnect the lines - just one bolt). With the radiator out you can blow out the oil cooler's and A/C fins.


I checked my Ron Davis Radiator with Debree Screen installed (1/4 inch mesh) and found trash on the front of the Ron Davis Radiator that had gotten through the screen. Following a Silage Truck with lots of small trash on the pavement did not help :D

What one needs for a perfect Debree Screen is a mesh size equal to or a bit smaller than the radiator pass through openings. But if one had a Debree Screen with that mesh size you are actually decreasing the air flow since the front Duct for Air Flow is actually smaller than the Front Face of the Radiator.
So......We are left with inspecting and cleaning the Radiators of trash from time to time and leave the Debree Screen to stop plastic bags, leaves, Dragon Flys ;)

You can clean the Radiator without removing as I found out. With a pressure washer I first pressure washed from the oil cooler adapter side the gap between the radiator and Oil Cooler.

Then carefully pressure washing directly (perpendicular to the surface) from the fan side of the radiator (each fan opening). Then again pressure washing from the oil cooler adapter side the gap between the radiator and Oil Cooler. But....be carefull with the pressure washer holding too close to the surface of the radiator or at an angle that may cause damage to the aluminum fins. On My Ron Davis absolutely no damage was done using a pressure washer as described herein.

The lower screws for the rad shroud are a PITA but the rest of the job is pretty straight forward. GC

You can reach in with a long open end and taking your time :p
.........remove the three (I think 7mm) screws on each side holding the lower part of the Radiator cowling in place. I replace ONLY the lower single 7mm screw when replacing the cowling. I will check if it is 6mm screw :D

[RussMcB]

<snip> ... since the front Duct for Air Flow is actually smaller than the Front Face of the Radiator.In race cars (and probably street cars, too), this is by design. Having a smaller opening than the radiator surface area slows down the air so it can transfer heat better.

[5ABI VT]

This has been on my mind a lot as of late. So far I am stuck with the multiple threads on corvette forum and other forums showing the cheaper brand radiators to work as well as the $$$ ones we have available. Personally I have an issue with trusting them because I want the best option regardless of cost but some posts show nearly identical rads for 1/3rd to 1/3 the price :/.

Anyhow I wanted to ask about cleaning methods. Anyone have any input on the best way to clean the rads out? My thoughts were soap and spray but if the crud is packed in the fins.. Maybe a long bristle brushed pressed into the rad? I don't want to be bending any fins etc.

I know generally oem stuff isn't the best vs aftermarket but I have spoken to a few people including Tom Dewitt about the actual benefits of more cores etc. from what I know, aluminum radiator requires much more surface area vs a brass/copper core radiator. I don't even remember what the oem radiators are made from?

My car is too clean to take down for rad cleaning I may drive it a few times first and let it get dirty before pulling it out. I will do a higher % mix of water with coolant and water wetter. I will make a thread showing what I find for sure. We had a very hot week last week but temps are dropping now so I don't really feel there is a 'need' for more cooling capacity like some of you who drive in extremely hot weather. I will start with cleaning it out and doing a t stat and drilling holes.

[5ABI VT]

Are lower temp t stats available for the lt5?

[QB93Z]

I have cleaned and reinstalled stock ZR-1 radiators 3 times and have removed and replaced 4 radiators, 2 DeWitts and 2 Ron Davis.

From my experience. the only way to "clean" a radiator that has blocked air flow is to remove the radiator from the car. The problem that I have seen is fine grit that is lodged between the fins. I have been able to remove most of the grit by laying the radiator flat on a concrete floor, lift it a few inches off the floor and then slamming in down flat against the floor. Do this once and then feel the grit that will be on the floor under the fin areas. Sweep the floor clean and repeat. Repeat until there is no more (or very little) grit coming out of the fins.

Do a before and after visual inspection through the fins looking toward a light or the sun. After the mechanical shock cleaning, you should see a noticeable difference in the air passages.

The first time I tried this method, I had removed the radiator and "cleaned" it with 100psi air blown "through" the radiator. The air cleaning is effective for removing leaves and candy wrappers from the front of the radiator, but proved to be ineffective at removing the grit blocking the air passages.

I would not recommend trying to clean the air passages mechanically because it is very hard to not deform the fins.

Good luck.

Jim

[GOLDCYLON]

Are lower temp t stats available for the lt5?


Yes im running a Ron Woods 160 T-Stat

[GOLDCYLON]

This has been on my mind a lot as of late. So far I am stuck with the multiple threads on corvette forum and other forums showing the cheaper brand radiators to work as well as the $$$ ones we have available. Personally I have an issue with trusting them because I want the best option regardless of cost but some posts show nearly identical rads for 1/3rd to 1/3 the price :/.

Anyhow I wanted to ask about cleaning methods. Anyone have any input on the best way to clean the rads out? My thoughts were soap and spray but if the crud is packed in the fins.. Maybe a long bristle brushed pressed into the rad? I don't want to be bending any fins etc.

I know generally oem stuff isn't the best vs aftermarket but I have spoken to a few people including Tom Dewitt about the actual benefits of more cores etc. from what I know, aluminum radiator requires much more surface area vs a brass/copper core radiator. I don't even remember what the oem radiators are made from?

My car is too clean to take down for rad cleaning I may drive it a few times first and let it get dirty before pulling it out. I will do a higher % mix of water with coolant and water wetter. I will make a thread showing what I find for sure. We had a very hot week last week but temps are dropping now so I don't really feel there is a 'need' for more cooling capacity like some of you who drive in extremely hot weather. I will start with cleaning it out and doing a t stat and drilling holes.


The OEM stuff is fine unless you started modding the engine. Keep in mind you have more than 20 years of sand and grit that has built up over the years between the fins and the end on the old units tend to be brittle and swell with age. You can get an OEM replacement for pretty cheap. I would pull it and make an assessment. If you start scrubbing you going to stat bending fins. After you pull it and tap it lighty on the driveway sand and silt wil stard dropping.

[Billy Mild]

Would it be worth having a radiator shop to clean the radiator?

[GOLDCYLON]

Would it be worth having a radiator shop to clean the radiator?


For as cheap as you can find an OEM replacement. I would say no. However that really depends on what they would charge.

[Billy Mild]

So is it even worth cleaning the radiator fins at all or just replace it since you have it out?

[5ABI VT]

Yes im running a Ron Woods 160 T-Stat

Are these available anywhere or discontinued?

Im a little :neutral: of dropping it on the pavement to get anything out as the plastic on the ends is joined somehow to the aluminum and I don't want to risk cracking any joints considering its been heat cycled throusands of times over 20 years. I will be pulling it out for sure and im fairly certain with 75k miles it wont be clean as new. I don't have any cooling isues besides the one hot day we had where I was parked with the a/c on I noticed the temp right at the warning zone. As soon as I turned the ac off it dropped and as I got on the road and to 40-50mph it dropped really fast. I am going to take a guess that based on what Ive seen one side of the rad will be jammed up very well most likely ahead of the primary fan. Ill be doing a spray soap clean and garden hose approach with no pressure and a soft bristle brush I purchased last night to try and get gunk out between the fins without bending anything. I shall report back !!

[5ABI VT]

Has anyone weighed a stock rad vs ron davis/fluidyne/dewitt ? If there is a weight savings I wont be cleaning the oem

[RussMcB]

My opinion only, maybe not the post you're hoping to hear...

I didn't weigh them when I swapped. but my opinion is the difference in weight is nothing any of us would ever notice. I mean, you could toss them both in the air pretty easily. A tiny fraction of the weight of the car.

However, I suppose it's possible a 4 core radiator might hold more coolant, and therefore might add a little weight, but again, negligible.

I was wishy-washy about changing mine, weighing the pros and cons, and eventually decided if people like Marc Haibeck recommends the Dewitt, might as well do it and (hopefully) solve all cooling issues and never worry about it again.

I will say, though, that even though the Dewitt is considered a "drop in", it still required some extra work to get it in. I'll elaborate if you want to hear.

[XfireZ51]

U may find that the fins bend even using a soft bristle brush. It doesn't take much.

[GOLDCYLON]

So is it even worth cleaning the radiator fins at all or just replace it since you have it out?

Maybe but it is exceedingly difficult without bending the fins. I would not even attempt it unless money was a crush. After 25 years it's time for a new radiator

[GOLDCYLON]

Are these available anywhere or discontinued?

Im a little :neutral: of dropping it on the pavement to get anything out as the plastic on the ends is joined somehow to the aluminum and I don't want to risk cracking any joints considering its been heat cycled throusands of times over 20 years. I will be pulling it out for sure and im fairly certain with 75k miles it wont be clean as new. I don't have any cooling isues besides the one hot day we had where I was parked with the a/c on I noticed the temp right at the warning zone. As soon as I turned the ac off it dropped and as I got on the road and to 40-50mph it dropped really fast. I am going to take a guess that based on what Ive seen one side of the rad will be jammed up very well most likely ahead of the primary fan. Ill be doing a spray soap clean and garden hose approach with no pressure and a soft bristle brush I purchased last night to try and get gunk out between the fins without bending anything. I shall report back !!


No idea on the T-Stat. I said tap not drop. Your talking about A 20-25 yo radiator and you are correct the plastic ends tend to swell over the years. Just order a OEM replacement they are fairly cheap.

[QB93Z]

So is it even worth cleaning the radiator fins at all or just replace it since you have it out?

That is always the question. I cleaned and reinstalled the radiator in my 140,000 mile Yellow ZR-1 just to see if the "slam cleaning" would work. And it did, after my cleaning, the cooling system worked properly and adequately for touring in a stock LT5, in Florida in the summer.

Jim

[5ABI VT]

My opinion only, maybe not the post you're hoping to hear...

I didn't weigh them when I swapped. but my opinion is the difference in weight is nothing any of us would ever notice. I mean, you could toss them both in the air pretty easily. A tiny fraction of the weight of the car.

However, I suppose it's possible a 4 core radiator might hold more coolant, and therefore might add a little weight, but again, negligible.

I was wishy-washy about changing mine, weighing the pros and cons, and eventually decided if people like Marc Haibeck recommends the Dewitt, might as well do it and (hopefully) solve all cooling issues and never worry about it again.

I will say, though, that even though the Dewitt is considered a "drop in", it still required some extra work to get it in. I'll elaborate if you want to hear.

From what I've read there needs to be some trimming done to make it fit.. That's really not much of a concern for me. our dollar up here tanked even further over the last 6 months so that puts a $500 radiator at around 750-800 all said and done. 6 months ago I could have shipped it to buffalo fudged a receipt and paid near $500 all in by picking it up. In a nutshell I don't have an issue spending the money IF the replacement was much better, lighter etc but seems the oem rad can easily handle what I have in our temps .. Even at 75k miles and uncleaned. Which makes it hard to spend the money to gain.. More capacity in higher temps which we don't have up here.

I have ideas of running coolant under the car and putting a rad where the spare tire is and directing air to cool it from there ! Would take a good 20+ lbs of a rad and coolant at the nose end and put it over the rear wheels or close ! :)

[mike100]

You can successfully clean the radiator- especially if removed ( I did 4 years ago). Even the inside was free of corrosion and no reason it couldn't transfer heat as well as a new unit, but eventually the side tank seal will let go.

[5ABI VT]

Are the base c4 and ZR-1 rads exactly the same ? I can't recall if we covered that here I googled it and got mixed replies. Have a friend with a Dewitt for his 96 LT4 car he never installed and sold his car so he's willing to sel it to me cheap.

[-=Jeff=-]

Are the base c4 and ZR-1 rads exactly the same ?.

Essentially yes

[secondchance]

Are the base c4 and ZR-1 rads exactly the same ? I can't recall if we covered that here I googled it and got mixed replies. Have a friend with a Dewitt for his 96 LT4 car he never installed and sold his car so he's willing to sel it to me cheap.

Dewitt offers single row and double row. I went with the double row version and very happy with it.
http://www.dewitts.com/collections/corvette-aluminum-radiators/products/1990-1996-aluminum-radiator

[secondchance]

You can successfully clean the radiator- especially if removed ( I did 4 years ago). Even the inside was free of corrosion and no reason it couldn't transfer heat as well as a new unit, but eventually the side tank seal will let go.

I went through two OEM radiators. In my case both failures were stress crack on the driver side, about 4-5 inches from the top, resulting from heat, expansion and contraction cycling. Sort of similar to aircraft developing stress fracture on the skin due to pressurization/depressurization cycle.

[Livin' in the 80's]

Has anyone tried using a powerful back pack blower to blow out the fins of the radiator and the oil cooler and ac condenser?

[XfireZ51]

Has anyone tried using a powerful back pack blower to blow out the fins of the radiator and the oil cooler and ac condenser?

Yes. It'll bend the fins

[QB93Z]

In my experience, the radiator fins become clogged with very fine sand. I had a radiator that was showing signs of insufficient cooling due to reduced air flow. I removed all the shrouds and the fans and fan assembly. Then I blew compressed air though the fins from the back using a stiff tubing with a right angle tip.

Then I removed the radiator and held it up to the sun and there were two circles (where the fans are) that let through less light than the edges.

I placed the radiator front down on the cement, lifted it about 6 inches and slammed it down on the concrete. On the cement, there were two circles of grit. I did this several times, then blew air through (backwards) and repeated.

I eventually got most of the fins cleared somewhat and reinstalled the radiator. I ended up replacing the radiator a few months later because I still felt that the air flow was reduced.

One good thing about removing the radiator was that I could straighten out all the fins that I bent using the pressurizer air wand.

Jim

[Billy Mild]

If the radiator is any age at all, just replace it with a new one. It is not worth cleaning it out. I cleaned mine and on installation the end tank failed. What a pain in the butt.

[Dynomite]

One item not discussed in this thread of which I have since experimented with is Engine RPM effects on Water Pump Flow and Engine Cooling.

1. Conditions

A. Fans turn on at 205 deg F and OFF at 200 deg F (Haibeck Chip)
B. I use 180 deg Thermostats.
C. Ron Davis, Dewitt, and Fluidyne multi core Aluminum Radiators.

2. My experience with Engine RPM (depending on Gear Driven 6th, 5th, 4th) in all ambient temperatures.

A. In sixth gear running 65 mph (less than 2,000 rpm) the Coolant always gets a bit over 200 deg F. On Hot days the coolant will get a bit over 213 deg F. The key is the Water Pump is not pushing enough flow through the fully open thermostat to cool the engine to a Temperature where the Thermostat takes over (180 deg F).

B. If I shift to 5th gear at 65 mph (more than 2,000 rpm) the coolant temperature drops to Thermostat control (180 deg F) on cool days and drops to near 200 deg F on Hot days.

http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite12/23d8abf6-05e1-436c-8049-d58b3ad16c03.png

3. Findings.

My findings are simply that the stock water pump is a bit low on coolant flow rate at rpms under 2,000 rpm. As you can see there is a big jump in Coolant Pump Flow rate between 1,000 rpm and 2,000 rpm and it is in this area or engine RPM that the Coolant Flow Rate is not sufficient in HOT Climates. This is specifically the overheating issue when idling at a stop sign on HOT days (100 deg +). If you raise the rpm from 800 rpm to say 2,000 rpm, coolant temperature will drop appreciably even though you are not moving.

The Coolant Pump Flow at 800 rpm is 15 gpm. The Coolant Pump actually gets more efficient as the rpm increases from idle to 2,000 rpm.

4. Water Pump Flow Rates.

As Per Marc Haibeck graph provided to the ZR-1 Net email list by Graham Behan about ten years ago, the Coolant Pump flow rate through the engine (not the radiator or thermostat) is:
15 gpm at 800 rpm
18 gpm at 1,000 rpm,
44 gpm at 2,000 rpm,
65 gpm at 3,000 rpm,
90 gpm at 4.000 rpm,
120 gpm at 5,000 rpm at which time cavitation is starting.

A. The Dual Thermostat Bypass pressure is apparently 5 psi and block resistance at 100 gpm is approximately 20 psi. I am not sure what the radiator Head Loss is at various flow rates but definitely depends on the radiator type.
B. It would seem that the Coolant Pressure Relief Cap on top of the Coolant Reservoir in front of passenger side set at 15 psi would assure the radiator maximum pressure would be 15 psi plus the Bypass Pressure of 5 psi or 20 psi.

See Item #5 The 180 deg versus the 160 deg thermostat or no thermostat (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1584987828)

[HAWAIIZR-1]

One item not discussed in this thread of which I have since experimented with is Engine RPM effects on Water Pump Flow and Engine Cooling.



1. Conditions



A. Fans turn on at 205 deg F and OFF at 200 deg F (Haibeck Chip)

B. I use 180 deg Thermostats.

C. Ron Davis, Dewitt, and Fluidyne multi core Aluminum Radiators.



2. My experience with Engine RPM (depending on Gear Driven 6th, 5th, 4th) in all ambient temperatures.



A. In sixth gear running 65 mph (less than 2,000 rpm) the Coolant always gets a bit over 200 deg F. On Hot days the coolant will get a bit over 213 deg F. The key is the Water Pump is not pushing enough flow through the fully open thermostat to cool the engine to a Temperature where the Thermostat takes over (180 deg F).



B. If I shift to 5th gear at 65 mph (more than 2,000 rpm) the coolant temperature drops to Thermostat control (180 deg F) on cool days and drops to near 200 deg F on Hot days.



http://i287.photobucket.com/albums/ll142/dynomite007/Dynomite12/23d8abf6-05e1-436c-8049-d58b3ad16c03.png



3. Findings.



My findings are simply that the stock water pump is a bit low on coolant flow rate at rpms under 2,000 rpm. As you can see there is a big jump in Coolant Pump Flow rate between 1,000 rpm and 2,000 rpm and it is in this area or engine RPM that the Coolant Flow Rate is not sufficient in HOT Climates. This is specifically the overheating issue when idling at a stop sign on HOT days (100 deg +). If you raise the rpm from 800 rpm to say 2,000 rpm, coolant temperature will drop appreciably even though you are not moving.



The Coolant Pump Flow at 800 rpm is 15 gpm. The Coolant Pump actually gets more efficient as the rpm increases from idle to 2,000 rpm.



4. Water Pump Flow Rates.



As Per Marc Haibeck graph provided to the ZR-1 Net email list by Graham Behan about ten years ago, the Coolant Pump flow rate is:

15 gpm at 800 rpm

18 gpm at 1,000 rpm,

44 gpm at 2,000 rpm,

65 gpm at 3,000 rpm,

90 gpm at 4.000 rpm,

120 gpm at 5,000 rpm at which time cavitation is starting.



A. The Dual Thermostat Bypass pressure is apparently 5 psi and block resistance at 100 gpm is approximately 20 psi. I am not sure what the radiator Head Loss is at various flow rates but definitely depends on the radiator type.

B. It would seem that the Coolant Pressure Relief Cap on top of the Coolant Reservoir in front of passenger side set at 15 psi would assure the radiator maximum pressure would be 15 psi plus the Bypass Pressure of 5 psi or 20 psi.



See Item #5 The 180 deg versus the 160 deg thermostat or no thermostat (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1584987828)


Always a wealth of valuable details and info Cliff. You mention in other posts that you never drill any holes in the thermostat. Is there any reason why you feel 1 or 2 (or more) holes is not good or will make a difference in the lower rpms off idle or while stuck in traffic? The reason I ask is my area puts me in a lot of bumper to bumper until I can get to the expressway. Thanks!!! Craig


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

[QB93Z]

Cliff, I agree completely with you analysis of the coolant flow at low engine RPM. I have observed that effect on many different ZR-1's.

With a brand new radiator, there is marginally enough coolant flow and air flow to maintain coolant temperature in the thermostat operating range. But as the radiator air flow is compromised due to fin blockage (ie age), the temperature of the coolant will rise until the larger coolant temp to air temp differential will allow more heat transfer and the coolant engine temperature will stabilized above 200 degrees.

Jim

[Dynomite]

Always a wealth of valuable details and info Cliff. You mention in other posts that you never drill any holes in the thermostat. Is there any reason why you feel 1 or 2 (or more) holes is not good or will make a difference in the lower rpms off idle or while stuck in traffic? The reason I ask is my area puts me in a lot of bumper to bumper until I can get to the expressway. Thanks!!! Craig


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

As I calculated, 1/8 inch diameter holes just are way to small compared to the wide open area available when the thermostat is completely open to have any effect. However, a few 1/8 inch diameter holes would not hurt anything as far as too low a temperature for the same reason and......these small holes will allow some air to travel from the engine to the top side of radiator when thermostat is still completely closed. I just do not bother with the holes and have no issues with air as I have explained in my Coolant Filling techniques discussions.

Also.......Marc suggested at one time the older Stants will deteriorate (Decrease in FUll Open Area) by up to 15% as they age. A thermostat with over 50k miles generally opens 5 degrees later and opens about 85% and that far exceeds the additional Coolant Flow Area created by small 1/8 inch diameter holes. SO......along with replacing Original Injectors, Refurbishing Original Starter Solenoids, Installing Aluminum Radiators in ZR-1s and Replacing ALL Fluids as part of Reconditioning, I also Install New Stant 180 deg Thermostats in ALL ZR-1s. Oh....and I also Install the Starter Relay and Carter Bling as part of Reconditioning and some other things. ;)

See Item #6 regarding additional holes in thermostats. The 180 deg versus the 160 deg thermostat or no thermostat (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1584987828)

Cliff, I agree completely with you analysis of the coolant flow at low engine RPM. I have observed that effect on many different ZR-1's.
With a brand new radiator, there is marginally enough coolant flow and air flow to maintain coolant temperature in the thermostat operating range. But as the radiator air flow is compromised due to fin blockage (ie age), the temperature of the coolant will rise until the larger coolant temp to air temp differential will allow more heat transfer and the coolant engine temperature will stabilized above 200 degrees.
Jim

Thank you Jim for the confirmation and I completely concur with your radiator cleaning techniques and discussions. There are many stock ZR-1 Radiators as well as relatively New Aluminum Radiators in ZR-1s compromised by leaves, plastic bags and Oil Cooler leakage creating an oily situation which collects dust on the Oil Cooler fins as well. There IS a reason for the Screen installation in front of the air flow opening on a ZR-1 as that will at least keep the leaves and plastics from stopping the air flow through a radiator. That additional screen is very accessible for inspection and very easy to clean of trash.

[A26B]

As I calculated, 1/8 inch diameter holes just are way to small compared to the wide open area available when the thermostat is completely open to have any effect.

Empirical trumps theoretical. Over the years, there have been numerous, noted improvements in cooling efficiency as a direct result of drilling holes in the thermostat flange. A very few follow.

1. Source-My personal experience; with a new Woods 160F thermostat on the bench, I decided to drill 3 holes in my "old" stat. The results were so definitive, I never replaced it with the 160F. [415ci, Ron Woods Radiator].

2. Source-Memory, not verified :); Secondchance here on the forum, had 3 holes drilled. Ran too cool in winter, replaced with another t-stat, drilled 1 hole & achieved desired results for year-round driving. [385ci, stock radiator].

3. Source-Memory, not verified :); XFireZ51 here on the forum, has 1 hole drilled. Desired improvement noted & retained as effective aid to cooling. [stock displacement? radiator?]

There are more cases of drilled t-stat flanges out there, I simply never took the time or made the effort to document them. I answer quite a few tech questions from Jerrys Gaskets customers, including cooling issues. I have drilled new thermostats by request before shipping to customers.

I don't take exception to your mathematics. I just believe the the holes have a more dynamic effect than simple enlargement of. cross sectional area. This is a subject worthy of documentation. In that regard, keeping it simple such as number of holes drilled & results restrained to categories such as "no change," "slight improvement," effective" & "excessive cooling."
I think there are too many variables to try & pin it down so the factors can be quantified & calculated.

It would be useful to read posts from those who have drilled t-stat flanges.

[Demps]

I have a good problem to have...I guess. I'll give my experience today...if I get to it after injectors, brake bleed, then thermostat drill.

Ted

[HAWAIIZR-1]

[QUOTE=Dynomite;259697]As I calculated, 1/8 inch diameter holes just are way to small compared to the wide open area available when the thermostat is completely open to have any effect. However, a few 1/8 inch diameter holes would not hurt anything as far as too low a temperature for the same reason and......these small holes will allow some air to travel from the engine to the top side of radiator when thermostat is still completely closed. I just do not bother with the holes and have no issues with air as I have explained in my Coolant Filling techniques discussions.



Also.......Marc suggested at one time the older Stants will deteriorate (Decrease in FUll Open Area) by up to 15% as they age. A thermostat with over 50k miles generally opens 5 degrees later and opens about 85% and that far exceeds the additional Coolant Flow Area created by small 1/8 inch diameter holes. SO......along with replacing Original Injectors, Refurbishing Original Starter Solenoids, Installing Aluminum Radiators in ZR-1s and Replacing ALL Fluids as part of Reconditioning, I also Install New Stant 180 deg Thermostats in ALL ZR-1s. Oh....and I also Install the Starter Relay and Carter Bling as part of Reconditioning and some other things. ;)



See Item #6 regarding additional holes in thermostats. The 180 deg versus the 160 deg thermostat or no thermostat (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1584987828)

Cliff,

Thanks for your thoughts. I did not think the 1/8" hole was for air and thought just to aid a little more coolant flow despite how little. It is amazing to hear how 3 holes can be too much and cause the car to run too cool in certain conditions. I know you spend a lot of time in your analyses and it is valued for sure.


Sent from my iPhone using ZR-1 Net Registry (https://siteowners.tapatalk.com/byo/displayAndDownloadByoApp?rid=90383)

[A26B]

Thinking your 160 deg thermostat was going to offer greater cooling at high temperatures is suspect thinking.....was that theoretical thinking? :D
I never thought such a thing, knowing well that a cooler thermostat can only enable, not create.[-X
Acquiring the 160F thermostat was not theoretical thinking, it was to be an experiment.:)

BTW I noticed several references in your posts pertaining to "up to 15% degradation" in thermostats as they age. That's a pretty broad range & doesn't actually state that any occurs at all. Details would really shine some light on this subject. Is it linear? does it always affect the range of the valve aperature?

[Hog]

OEM radiator
YEARS 1990-92 1993-1995 Core Thickness 1.34 in. Same Frontal Area 405 sq. in. Same Radiator Cap 17 psi. Same Thermostat Open 180 degree F Same Fully Open 195 degree - 200 degree F Same

Coolant pump
YEARS 1990-92 1993-1995 Type Centrifugal Same Capacity 12 gpm @ idle 85 gpm @ 7,000 rpm Same Supplier Ace (Casting) Same