Radiator options

[Karl]

Mine is leaking and I want to know is the factory unit a one or two row/core unit?

After reading Dominicks summary of the Fluidyne unit I do not see any advantages over the stock unit.

[tomtom72]

The OEM & replacement radiators from chevy ( if they still have them? ) are a single core or just one row of tubes. They are not all that small, but them I'm sure the aftermarket units are double row units.

:cheers:
Tom

[5ABI VT]

The little that I know I believe oem use brass or copper which is much better than aluminum. I think that is the main reason for requiring 2 Rows which is to match the efficiency. The added cooling comes from the additional capacity. That's as much as I rebember when I researched into it but I'm going to be looking for a radiator soon myself because I'd like to move to an electric water pump as well.

[tomtom72]

:o Actually the OEM and OE replacement stuff is aluminum. I don't know that even the aftermarket stuff uses any thing but aluminum.

The only rub with the ACDelco replacement units is that they are universal with respect to transmission. They all have the cooler in the right tank for the auto equipped C4's.

The aluminum is not an issue as long as you keep up with coolant maintenance, keep the grounds clean, and have no gasket leaks.

:cheers:
Tom

[Scrrem]

My only issue with aluminum radiators like Ron Davis, is that they don't have a drain petcock. It makes draining a real mess.
Rich

[Hib Halverson]

Thought I'd "weigh-in" on the radiator issue because, back in the late 90s, I did a lot of cooling performance development on ZR1s–including doing most of the product development for Fluidyne on its late C4 radiator.

First, the above comment about aftermarket radiators generally not having drains. Pure bunk. The Ron Davis might not have one, but most others such as DeWittt and Griffin and, also, the Fluidyne have them.

The stock radiator is not copper-brass. It's an aluminum core with plastic tanks. The radiator is one places GM "cheaped-out" on the ZR1. The car should have received a specific radiator of all-aluminum construction. That would have allowed GM to have a slightly larger radiator for the LT5's extra power output and it would have allowed GM to reduce the amount of coolant bypassed around the radiator during high rpm operation.

Lastly, the OP's comment about "Dominick" stating that the Fluidyne (or any other aftermarket radiator for that matter) being no better at cooling than the OE radiator is not based on any facts.

Reality is that combined with a 180° or 170° thermostat and lower fan-on temps, the Fluidyne and other aftermarket C4 radiators are guide good at improving cooling performance.

[XfireZ51]

My comments regarding the performance of the Fluidyne dealt w the fact it was actually too good at cooling the motor. During a recent drive in 35F weather, the coolant temp had much difficulty getting above the temp for allowing Closed Loop operation. It worked fine in summer and fall temps. My OE radiator needed to be cleaned and I decided to swap in the Fluidyne for extra cooling w A/C. My wife won't get in the car during the summer unless I run the A/C.
I'm using stock thermo.

[PhillipsLT5]

Thought I'd "weigh-in" on the radiator issue because, back in the late 90s, I did a lot of cooling performance development on ZR1s–including doing most of the product development for Fluidyne on its late C4 radiator.

First, the above comment about aftermarket radiators generally not having drains. Pure bunk. The Ron Davis might not have one, but most others such as DeWittt and Griffin and, also, the Fluidyne have them.

The stock radiator is not copper-brass. It's an aluminum core with plastic tanks. The radiator is one places GM "cheaped-out" on the ZR1. The car should have received a specific radiator of all-aluminum construction. That would have allowed GM to have a slightly larger radiator for the LT5's extra power output and it would have allowed GM to reduce the amount of coolant bypassed around the radiator during high rpm operation.

Lastly, the OP's comment about "Dominick" stating that the Fluidyne (or any other aftermarket radiator for that matter) being no better at cooling than the OE radiator is not based on any facts.

Reality is that combined with a 180° or 170° thermostat and lower fan-on temps, the Fluidyne and other aftermarket C4 radiators are guide good at improving cooling performance.

My fluidyne has a drain, I bought this years ago based on Hib's suggestion & very pleased even in HOT AZ

[Dynomite]

My only issue with aluminum radiators like Ron Davis, is that they don't have a drain petcock. It makes draining a real mess.
Rich

My Ron Davis radiator has a threaded drain port near bottom right hand (passenger) side ;)

[Scrrem]

My Ron Davis radiator has a threaded drain port near lower right hand (passenger) side ;)

Mine does too but would like a petcock, I can't use a brass petcock....that's a receipe for disaster with corrosion, the metals are not compatable. I have been looking to find a plastic one, but haven't been sucessful yet.
Rich

[Karl]

My comments regarding the performance of the Fluidyne dealt w the fact it was actually too good at cooling the motor. During a recent drive in 35F weather, the coolant temp had much difficulty getting above the temp for allowing Closed Loop operation. It worked fine in summer and fall temps. My OE radiator needed to be cleaned and I decided to swap in the Fluidyne for extra cooling w A/C. My wife won't get in the car during the summer unless I run the A/C.
I'm using stock thermo.

Maybe I was mistaken but I believe sitting in traffic with the.AC on the fluidyne radiator got up to 227 which is marginally better than stock.

I like to use the air conditioner. Combine that with a hot humid summer day in traffic 227 and rising is not where I want to be.

I have a under drive water pump so that does not help.

I went with a champion three core unit. Should be here and in soon.

Also looking at upgrading the cooling fans if need be.

[secondchance]

I got tired of OEM radiors failing, typically, at plastic tank - went through two of them.
Also, after going to 380 (378 really...) my LT5 is certainly putting out more heat. I considered Fluiddyne, Ron Davis but had some concern for extra thickness of Ron Davis and ability to pull air through it with fans. As for the Fluidyne, I could not confirm number of cores (one or two). For these reasons, I eventually settled for a Dewitt dual core version. Matter of fact, it's waiting for me at the Westminster WAZOO HQ to be installed. Once I get it installed and face 90 degree plus weather, I will report back my findings.

XfireZ51,

Have you checked your thermostat? Sounds like it may have failed in open position.

[Hib Halverson]

My comments regarding the performance of the Fluidyne dealt w the fact it was actually too good at cooling the motor. During a recent drive in 35F weather, the coolant temp had much difficulty getting above the temp for allowing Closed Loop operation. It worked fine in summer and fall temps. My OE radiator needed to be cleaned and I decided to swap in the Fluidyne for extra cooling w A/C. My wife won't get in the car during the summer unless I run the A/C.
I'm using stock thermo.

If you have an OE 195° thermostat and the engine won't warm enough for closed loop, your thermostat is faulty. It's likely stuck open or is not fully closing.

Maybe I was mistaken but I believe sitting in traffic with the.AC on the fluidyne radiator got up to 227 which is marginally better than stock.

I like to use the air conditioner. Combine that with a hot humid summer day in traffic 227 and rising is not where I want to be.

I have a under drive water pump so that does not help.

I went with a champion three core unit. Should be here and in soon.

Also looking at upgrading the cooling fans if need be.

Underdriven water pump...big mistake. The stock pump is already "under driven" at idle and low speeds. That's why most ZR1s at freeway speeds run hotter in sixth gear than they do in fifth.

Do not "upgrade" your fans. Have someone who can calibrate lower the fan-on temps in the "chip". You can increase airflow until the cows come home, but if you don't revise the fan-ons, the car will still tend to run warm because the fans don't come on at a low enough temperature.

When I did Fluidyne's hot weather testing in the Summer in Palm Springs CA, the Fluidyne radiator, combined with a 170° thermostat, lowered antifreeze concentration and lower fan-ons had my ECT 208-212 in congested traffic, A/C on and an OAT of 108°F

[XfireZ51]

The motor would warm up when sitting at idle but would quickly cool down at cruising speeds.

[Karl]

Underdriven water pump...big mistake. The stock pump is already "under driven" at idle and low speeds. That's why most ZR1s at freeway speeds run hotter in sixth gear than they do in fifth.




Please elaborate more in this.

Thanks.

[Hib Halverson]

Please elaborate more in this.

Thanks.

Drive your ZR-1 at 65-mph in sixth gear for 5 miles monitoring ECT.

Then, drive the car at the same speed in fifth gear for 5 miles monitoring ECT.

Chances are the engine will run hotter at 65-mph in sixth and at 65-mph in fifth.

Post your findings.

[Hog]

Drive your ZR-1 at 65-mph in sixth gear for 5 miles monitoring ECT.

Then, drive the car at the same speed in fifth gear for 5 miles monitoring ECT.

Chances are the engine will run hotter at 65-mph in sixth and at 65-mph in fifth.

Post your findings.
Another reason for 4.10's gears.

[Karl]

Drive your ZR-1 at 65-mph in sixth gear for 5 miles monitoring ECT.

Then, drive the car at the same speed in fifth gear for 5 miles monitoring ECT.

Chances are the engine will run hotter at 65-mph in sixth and at 65-mph in fifth.

Post your findings.

I have noticed this.

It seems that your original comment implied the under drive water pump is not worth any type of performance gain versus stock. I have always thought a under drive pump will add some power to any engine.

So do you think there is any performance gain, hp wise, with using a under drive water pump?

[WARP TEN]

......Do not "upgrade" your fans. Have someone who can calibrate lower the fan-on temps in the "chip". You can increase airflow until the cows come home, but if you don't revise the fan-ons, the car will still tend to run warm because the fans don't come on at a low enough temperature......

Marc sets both fans to come on at ECT of 205 degrees. Mine runs about 190-195 normally to a max of about 208 on the hottest days. --Bob

[Pete]

Karl,5th and 6th gear issue is not the UD pulley, stock pulley has the same issue so lets not freak out here.

The UD pulley slows the pump down if you had cooling issues before Hib is right went the wrong way with the UD pulley.
The UnderDrive pulleys give you more RPM before it goes to bypass,the Road Racing guys like this.

Heck,my Z has no A/C condenser, no oil cooler, 160 T-Stat, fans on at 175*, stock pulley and still have the 5th 6th gear issue.
Like Dom said when she gets moving she cools faster.

The C4 is a bottom feeder sucks up a lot of crap, take radiator out clean it very good,usually you will find a birds nest in there you will be suprised i would suggest either take Dom's radiator and clean it up or buy new cause you don't wanna do the job twice not a fun job.

I have these pulleys on my Z (stock size).
What i like about the pulleys is they are aluminum, half the weight of the OE steel pieces between PS,WP & ALT i saved about 2-3 lbs and they look nicer then the OE pulleys and get them in any common color,even purple.

By the way you will not get her to run below 220* on a 90+* hot n humid Chicago parking lot traffic day, i tried everything this is why i don't have it anymore the ones that say there's stays at 200 or 210 they are talking at speeds not parking lot traffic.

Pete

[Karl]

Karl,5th and 6th gear issue is not the UD pulley, stock pulley has the same issue so lets not freak out here.

The UD pulley slows the pump down if you had cooling issues before Hib is right went the wrong way with the UD pulley.
The UnderDrive pulleys give you more RPM before it goes to bypass,the Road Racing guys like this.

Heck,my Z has no A/C condenser, no oil cooler, 160 T-Stat, fans on at 175*, stock pulley and still have the 5th 6th gear issue.
Like Dom said when she gets moving she cools faster.

The C4 is a bottom feeder sucks up a lot of crap, take radiator out clean it very good,usually you will find a birds nest in there you will be suprised i would suggest either take Dom's radiator and clean it up or buy new cause you don't wanna do the job twice not a fun job.

I have these pulleys on my Z (stock size).
What i like about the pulleys is they are aluminum, half the weight of the OE steel pieces between PS,WP & ALT i saved about 2-3 lbs and they look nicer then the OE pulleys and get them in any common color,even purple.

By the way you will not get her to run below 220* on a 90+* hot n humid Chicago parking lot traffic day, i tried everything this is why i don't have it anymore the ones that say there's stays at 200 or 210 they are talking at speeds not parking lot traffic.

Pete

I never had any overheating issues unless I was stuck in traffic with the AC on.

[Pete]

I never had any overheating issues unless I was stuck in traffic with the AC on.


Karl,not overheating but cooling her down with A/C on in traffic.
I should've made it more clear with the A/C on in traffic i just thought it was understood.
A friend has a 1994 with 17k miles and has cooling issue with A/C on in traffic.
This is C4 issue.
I think a nice pusher fan could help.
Most BMW's,Mercedes, have pusher fans my Infiniti has belt driven fan and an electric pusher fan.

Pete

[XfireZ51]

And I swapped in a Fluidyne because I experienced overheating when driving in the Woodward Cruise. Ambient temps must have been over 90F. DID NOT have A/C on. Traffic was crawling. Took an hour to move 1 mile. With the Fluidyne installed, I actually raised the Fan Temps.

[Karl]

Karl,not overheating but cooling her down with A/C on in traffic.
I should've made it more clear with the A/C on in traffic i just thought it was understood.
A friend has a 1994 with 17k miles and has cooling issue with A/C on in traffic.
This is C4 issue.
I think a nice pusher fan could help.
Most BMW's,Mercedes, have pusher fans my Infiniti has belt driven fan and an electric pusher fan.

Pete

Here is the thread we were texting about earlier

http://www.zr1.net/forum/showthread.php?t=22859&highlight=pusher+fan

[Pete]

Here is the thread we were texting about earlier

http://www.zr1.net/forum/showthread.php?t=22859&highlight=pusher+fan


Thank You Mr. Davila
Now the question remains is it Frank Approved.:)

Pete

[Hib Halverson]

I have noticed this.

It seems that your original comment implied the under drive water pump is not worth any type of performance gain versus stock. I have always thought a under drive pump will add some power to any engine.

So do you think there is any performance gain, hp wise, with using a under drive water pump?

Regardless of any power gain, why would I want to under drive my water pump and make cooling worse? But..I digress.

Do I think there is any power gain by under driving the coolant pump? At high rpm there might be a small gain.

[Hib Halverson]

Karl,not overheating but cooling her down with A/C on in traffic.
I should've made it more clear with the A/C on in traffic i just thought it was understood.
A friend has a 1994 with 17k miles and has cooling issue with A/C on in traffic.
This is C4 issue.
I think a nice pusher fan could help.
Most BMW's,Mercedes, have pusher fans my Infiniti has belt driven fan and an electric pusher fan.

Pete

Why not solve the problem rather than adding "pusher fans"? It might be easier and less expensive.

[Pete]

Why not solve the problem rather than adding "pusher fans"? It might be easier and less expensive.


Hib,i have tried a lot of different ways to keep the temps from creeping up in traffic with A/C on, clean radiator,new radiator,big radiator,fans on early,low temp t-stats,and this is on multiple Z's.
So i yanked the A/C on my Z and decided if i'm going to drive in traffic on hot summer days i will take my other car with no worries,now my Z is just a toy/weekend warrior :-D

If you have some input/suggestions on this please let me know i'm always open to suggestions/input that i can try,maybe i missed something.

I even tried a 55 GPM electric pump worked good with no A/C but again with A/C on in traffic temps would creep upwards soon as i get some speed it would drop like a rock my conclusion need more air thru the radiator in traffic.

I'm one guy that likes his temps down.
I don't like to see temps over 220-225 if we can keep them steady at 200 it would work for me (A/C on in traffic).:)

We have to understand when your in summer traffic it could take you
1 hour to go 2-3 miles (on the highway) it's stop n go you'll move 5 feet stop 2 minutes move another 5 feet it's ridiculous no air moving thru the radiator.

I'm pretty sure Mr Davila has also tried different things to keep temps down he's still trying from the looks of the install of a pusher fan,this was going to be my next move since Mr Davila did it with good results i don't have to experiment.

What got me thinking about the pusher is my Infiniti and other luxury cars have belt driven fans and an additional electric pusher fan when i turn my A/C on in the Infiniti the pusher fan comes on,this gets me to think if these high priced luxury cars (BMW & Mercedes) did not have cooling issue why add an extra part they could be saving millions,just a thought.


My set up now is no oil cooler to me it's a waste since t-stat doesn't fully open till 200*, no condenser, 160 t-stat,stock clean radiator,fans on at 175* off at 170*,70/30 mix, Redline water wetter i have been using Redline water wetter for many years even in my other cars, when my Z sits and idles you'll hear my fans come on and go off it will keep cycling like this no matter outside temps,in traffic she will stay steady at 180-185 soon as i get some speed she cools down fast but i would like to keep her steady at 175* no matter what.
Oil temps are always within 10* of coolant temps.
I do not road race my Z just 1/4 and 1/2 mile, love to do 1 mile.

Man i think i broke a finger typing all this.
Pete

[Dynomite]

Hib,i have tried a lot of different ways to keep the temps from creeping up in traffic with A/C on, clean radiator,new radiator,big radiator,fans on early,low temp t-stats,and this is on multiple Z's.
So i yanked the A/C on my Z and decided if i'm going to drive in traffic on hot summer days i will take my other car with no worries,now my Z is just a toy/weekend warrior :-D

If you have some input/suggestions on this please let me know i'm always open to suggestions/input that i can try,maybe i missed something.

I even tried a 55 GPM electric pump worked good with no A/C but again with A/C on in traffic temps would creep upwards soon as i get some speed it would drop like a rock my conclusion need more air thru the radiator in traffic.

I'm one guy that likes his temps down.
I don't like to see temps over 220-225 if we can keep them steady at 200 it would work for me (A/C on in traffic).:)

We have to understand when your in summer traffic it could take you
1 hour to go 2-3 miles (on the highway) it's stop n go you'll move 5 feet stop 2 minutes move another 5 feet it's ridiculous no air moving thru the radiator.

I'm pretty sure Mr Davila has also tried different things to keep temps down he's still trying from the looks of the install of a pusher fan,this was going to be my next move since Mr Davila did it with good results i don't have to experiment.

What got me thinking about the pusher is my Infiniti and other luxury cars have belt driven fans and an additional electric pusher fan when i turn my A/C on in the Infiniti the pusher fan comes on,this gets me to think if these high priced luxury cars (BMW & Mercedes) did not have cooling issue why add an extra part they could be saving millions,just a thought.

My set up now is no oil cooler to me it's a waste since t-stat doesn't fully open till 200*, no condenser, 160 t-stat,stock clean radiator,fans on at 175* off at 170*,70/30 mix, Redline water wetter i have been using Redline water wetter for many years even in my other cars, when my Z sits and idles you'll hear my fans come on and go off it will keep cycling like this no matter outside temps,in traffic she will stay steady at 180-185 soon as i get some speed she cools down fast but i would like to keep her steady at 175* no matter what.
Oil temps are always within 10* of coolant temps.
I do not road race my Z just 1/4 and 1/2 mile, love to do 1 mile.

Man i think i broke a finger typing all this.
Pete

I concur.........mostly ;)

I am talking 100+ deg F days and stop and go traffic or long stop lights in succession.

I like my LT5 running around 190 deg F to 200 deg F on the HOT days for condensation and best performance. I use the Haibeck LT5 Performance Chips (http://www.zr1specialist.com/HAT%20Web/products/LT5%20Performance%20Engine%20Calibrations.htm) in ALL ZR-1s which turn Fans ON at 205 deg F and OFF at 200 deg F.

Now also keep in mind you are pulling air through a three stack set up including the Oil Cooler, AC condenser, and Radiator. That is where the pusher fan concept will help in stop and go traffic or at stop lights if you want to go that route. I think Daryll (AKA Goldcylon) experimented with higher flow rate dual fans which would also help keep LT5 Coolant temperatures down on HOT days.

A. Now where I think concepts are over blown.............
The steady state of the coolant flow is identical at HOT ambient temperatures (100+ deg F) no matter when the fans first came on and no matter when the thermostat first opened. (kind of like using lighter weight front of engine pulleys or lighter weight flywheels where the hp gain is only on rotational acceleration and not on the steady state of engine RPM).

Using 165 deg F or anything less than 180 deg F thermostats is a bit of a waste and a negative on colder days. A 180 deg F and a 165 deg F thermostat are both fully open at the LT5 operational temperatures I am seeking of 190 deg F - 200 deg F (maybe 215 deg F on HOT 100+ deg F days). Yes you may if other modifications allow it on 100 deg F days drive around at 175 deg F and approach a stop and go situation with a cooler engine buying you some time at the stop and go. But that is about the only difference.

Same goes with turning fans on at lower temperatures than 205 deg F. I do not want to run around on cooler days with the fans always running when they do not have to in view of my 180 deg F thermostat and in view of the 190 deg F - 200 deg F LT5 temperatures I am seeking (maybe 215 deg F on HOT 100+ deg F days).

B. What to do to keep the LT5 Cooler in Stop and Go or Long Stop Lights on HOT (100+ deg F) days..................
So....if you want to get serious and like Pete suggests....do all the normal maintenance like clean radiator, oil cooler, and AC condenser of trash (keep the stack clean and that includes keep the stacks clean of any oil). If you want additional LT5 performance get yourself one of the Haibeck LT5 Performance Chips (http://www.zr1specialist.com/HAT%20Web/products/LT5%20Performance%20Engine%20Calibrations.htm) which turn Fans ON at 205 deg F and OFF at 200 deg F.

If you really want to get serious......install an auxiliary electric pusher fan or higher flow rate dual fans. And/or install an Aluminum After Market Radiator that offers greater cooling effect with the same coolant flow rate (but at the same time may be a bit more restrictive on the air flow rate).

If you really really want to get serious.....remove the oil cooler and AC condener. But when I am that serious :D I just turn AC off and if I have to .....turn the engine off.

C. Underdrive and Overdrive Water Pump Pulleys as they relate to Engine Cooling...............
Oh.....just to complete this little discussion I am having :D
Using a larger diameter water pump pulley (Underdrive) may buy you some engine cooling at higher RPMs if you are in the 6000-7000 rpm zone for very long where the water pump may be cavitating at that high rpms with a standard diameter water pump pulley. On the other hand, using a smaller diameter water pump pulley (Overdrive) may buy you some engine cooling at lower rpms in stop and go traffic where the coolant flow rate is normally low with a standard diameter water pump pulley.

See LT5 Engine Cooling Issues on Hot Days (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-8.html#post1587653777)

See LT5 Engine Optimum Operating Temperatures (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-8.html#post1587653780)

See Primary Cooling Fan Operation Criteria TIPS (http://www.zr1.net/forum/showthread.php?p=207317)

[Karl]

Pete hit the nail on the head.

I have got caught in rush hour traffic on hot and humid days and as long as the car is moving there are no worries but once stuck and not moving things begin to heat up.

I am 100% convinced that air flow is the key and like Hib said earlier GM half assed on the LT-5 cooling with the standard C4 radiator. Either higher CFM fans (like that in the Ford Taurus, Crown Vic, or Dodge Vper) or a simple pusher fan up front. Seems like Tony's test results confirm it works.

I never had cooling problems with the under drive water pump pulley. Just standard C4 warming up while not moving in traffic with the A/C on. I would like my car to run in the 180*- 190* range all the time if I had it my way. My new 3 core aluminum radiator should be here soon and in the car right away.

[Karl]

Been looking at Porsche 928's (not to purchase) and they all have pusher fans in front.

Looks like that is the key to a cool engine with the a/c on stuck in traffic.

https://www.google.com/search?q=porsche+928+chevy+v8&biw=1140&bih=652&tbm=isch&imgil=dt7Y_5gjiCG_IM%253A%253B8V2CjAz6HdVj_M%253Bh ttp%25253A%25252F%25252Fforums.pelicanparts.com%25 252Fporsche-928-technical-forum%25252F682455-chevy-conversion.html&source=iu&pf=m&fir=dt7Y_5gjiCG_IM%253A%252C8V2CjAz6HdVj_M%252C_&usg=__O4t9gASriRZTByceIAbGyBLFb4w%3D&ved=0CDoQyjc&ei=03OTVJyCC4mrgwTEnYOIAg#facrc=_&imgdii=_&imgrc=yvwG-NMeFbALqM%253A%3BaJMAlN4V16JgsM%3Bhttp%253A%252F%2 52Fbringatrailer.com%252Fwp-content%252Fuploads%252F2009%252F02%252F1978_Porsc he_928_Brown_Coupe_For_Sale_Engine_1.jpg%3Bhttp%25 3A%252F%252Fwww.cadillacforums.com%252Fforums%252F cadillac-forum%252Ft-214590.html%3B480%3B360

[rkreigh]

my temps creep up a bit with the ac on in traffic

the ron davis helps "recover quicker" once moving but to me the stock fans just aren't strong enough to pull the cfm required in stop and go

I'm curious why Hib you don't think more fan flow will help?

I like the fluidyne core with the heavy duty oil cooler

it seems more logical than "stacking" the components and the core is more efficient and a bit thinner so the fans aren't over stressed trying to pull air through the really thick cooling stack which I believe is the problem

I got dewitts fans setup which looks nice, when summer arrives I'll let you know if it helps!

[Pete]

Some early C4's had a pusher fan from the factory.

Freaken bean counters.

Pete

[Hib Halverson]

(snip)
I'm curious why Hib you don't think more fan flow will help?
(snip)



If the cooling system is working properly and you've got the right combination of coolant, thermostat, fan-on cal and radiator, in my experience, ECT, even with the A/C on is not an issue.

Well...unless your goal is to have ECT below 210 or so with the AC on. If you feel the need for that then you have to look at additional modifications such as an even bigger radiator and, well...maybe more air flow.

So, in theory, sure more flow from the fans might further cool the engine but I'm really only interested in what's necessary rather than what's possible.

That said, if you were going to go for more air flow, you'd have to upgrade the electric fan electrical to support fan motors which draw more current.

Lastly, I didn't know Fluidyne now made a radiator with an EOC built in. If that's the case, I agree, it makes more sense.

[Dynomite]

my temps creep up a bit with the ac on in traffic

the ron davis helps "recover quicker" once moving but to me the stock fans just aren't strong enough to pull the cfm required in stop and go

I got dewitts fans setup which looks nice, when summer arrives I'll let you know if it helps!

It is Ambient Temperatures of 100+ deg F that cause the LT5 Hot issues. It becomes obvious to me that Air Flow is the culprit in that once the ZR-1 is moving at say 20-30 mph the Coolant temperatures quickly get back in the 200 - 210 deg F range. The LT5 engine is rapidly cooled from 215+ deg F (higher if I did not turn off AC) with the ZR-1 not moving on 100+ deg F days once the Dynamic Air Flow is created by moving forward at 20-30 mph.

So the additional Air Flow required to do that (keep the engine in the 200 deg F - 210 deg F Range on a 100+ deg F day) is obviously that Air Flow hitting the front of the ZR-1 at 20-30 mph. I am thinking one can get higher pressurized Air Flow with a Pusher Fan within say 1/4 inch of the front of the ZR-1 Cooling Stack pushing Air through that stack.

1. The First Trick then since we can assume the Tony Davila Pusher Fan Solution (http://www.zr1.net/forum/showthread.php?t=22859&highlight=pusher+fan) works is to refine that solution such that the fix for a temporary LT5 HOT situation on a HOT day does not interfere with the normal Cooling of the ZR-1 Cooling Stack using only Stock Fans.

2. The Second Trick would be to operate that Pusher Fan(s) only when in stop and go traffic on a HOT day using a simplified Relay that can be activate remotely. The Relay wired directly from the battery to the Push Fan. No Modifications to ANY existing Electrical wiring or Electronics.
This would make for a very simple and inexpensive Solution to an otherwise complicated problem ;)

12V 15A Relay Remote Control Kit DC Connector 15 amp Heavy Duty (http://www.ebay.com/itm/Logisys-RM02-12V-15A-Relay-Remote-Control-Kit-DC-Connector-15-amp-Heavy-Duty-/380427545278?pt=LH_DefaultDomain_0&hash=item58933faabe)

3. The third Trick is to identify and control how much Air (using Stock Dual Fans or Stock Dual Fans with an Auxiliary Pusher Fan) Passes Through the AC Condenser, Oil Cooler, and Radiator rather than go around (through the gap) between the AC Condenser and Oil Cooler.....and through the gap between the Oil Cooler and Radiator. When you turn off the AC, The AC Condenser is not heating up the air passing through. The Oil Cooler is contributing (Oil Temperature Thermostat-Open-203 degree F, Fully open-266 degree F). Engine Lubrication System Functional Discussion (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp.html#post1580467622)

4. Or......install higher flow rate Puller Dual Fans replacing the Stock Puller Fans. But then we have a situation where we are pulling more air 99+% of the time when we do not have to.

See LT5 Engine Cooling Issues on Hot Days (http://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-8.html#post1587653777)

[Karl]

So I went with the Fluidyne and installed a 13" spall pusher fan rated at 1360 cfm in front that I will wire up later to a separate on/off switch for extreme hot weather conditions.

The three row looked easy enough to install but I was not able to guarantee a snug and tight fit without removing the a/c condenser and oil cooler to check clearances. Cutting the lower mounts would have been easy enough using a micro dremel. All my a/c stuff is new and I don't want to touch it so I had to change plans.

The swap was pretty easy after taking my time and using a 7mm ratchet wrench to help get the job done.

Anyway I have a question for the Fluidyne what size is this fitting?

It's not a 1/8" so I am guessing 6mm or such? I am going to call Fluidyne tomorrow but thought I would ask here.

http://s5.postimg.org/7qer9bosz/20150101_175924.jpg (http://postimg.org/image/7qer9bosz/)

This is the line that goes from the fill tank to the radiator. The factory radiator has a male connector the hose slides over.

Guess the Fluidyne is not a direct fit after all...

[XfireZ51]

Karl,

Pretty sure I used a pipe fitting. Had to slip the hose over it. Pete should be able to answer your question. He did for me, I just can't recall the spec right now.

[Hib Halverson]

(snip)

I'm curious why Hib you don't think more fan flow will help?

(snip)

Well...all I can say is my ZR1, at the 500-hp level cools fine...even in traffic in Palm Springs in the summer. The one thing I haven't done is continuous lapping at a track day in the summer. It's possible that a lot of high rpm in hot weather might have the coolant bypass a problem.

Beyond that, now that I've read some more of this thread, the argument about fans seems pointless.

Pushers, pullers...if people don't think there's enough airflow, add both!

[WVZR-1]

So I went with the Fluidyne and installed a 13" spall pusher fan rated at 1360 cfm in front that I will wire up later to a separate on/off switch for extreme hot weather conditions.

The three row looked easy enough to install but I was not able to guarantee a snug and tight fit without removing the a/c condenser and oil cooler to check clearances. Cutting the lower mounts would have been easy enough using a micro dremel. All my a/c stuff is new and I don't want to touch it so I had to change plans.

The swap was pretty easy after taking my time and using a 7mm ratchet wrench to help get the job done.

Anyway I have a question for the Fluidyne what size is this fitting?

It's not a 1/4" so I am guessing 6mm or such? I am going to call Fluidyne tomorrow but thought I would ask here.

http://s5.postimg.org/7qer9bosz/20150101_175924.jpg (http://postimg.org/image/7qer9bosz/)

This is the line that goes from the fill tank to the radiator. The factory radiator has a male connector the hose slides over.

Guess the Fluidyne is not a direct fit after all...

I would think that fitting size is 1/8NPT which is 27 TPI. I wouldn't think they would mix a metric spec into a product where ANSI specs have been used for so many years. First hand knowledge -NO but it would be my first choice to try. It is a tapered spec so you can expect a friction tightening at maybe 6 - 8 threads. I believe a total of likely 10 threads on the appropriate fitting.

[Karl]

Typo, I have a 1/8" npt fitting and it is the wrong size.

[WVZR-1]

Typo, I have a 1/8" npt fitting and it is the wrong size.

1/16-NPT then and it's still 27TPI. 1/16 NPT certainly isn't found very often but I'd guess it's what you've found OR maybe actually a metric affair but it sure would seem unlikely. I would think they would have supplied information and I might have guessed even applied a sticker/decal or something to keep the user from screwing up an initial install.

*** I doubt the metric and am inclined to think the 1/16-NPT. If you do call I'd be interested in an explanation of "WHY". Maybe there's a very good reason.

[Karl]

It's 1/8" npt and so far so good.

Fluidyne didn't return my phone calls either. Oh well.

[-=Jeff=-]

So is a 3 core overkill? S that ever decided in this thread?

[8cam]

Been looking at Porsche 928's (not to purchase) and they all have pusher fans in front.

Looks like that is the key to a cool engine with the a/c on stuck in traffic.



I have some experience here, having run a couple 928s and done significant cooling upgrades on one of them. Funny the 928 guys usually convert to a PULLER for upgrades. They use a similar radiator, aluminum core with plastic side tanks and those tanks are the achilles heel. The 928 flow design causes a hot spot at the top of the tank, which will eventually cause it to split. With a replacement factory radiator at $1,200 going with aftermarket was a no brainer. I installed a Griffin with full aluminum tanks and a BIG Spal puller fan, with an in-line thermostat. That completely solved the car's cooling problems.

I do believe the stock system was excellent and worked well, if it was in good condition. But over the years, tubes clog, vanes get bent, things can corrode, and it wasn't working like it was designed to. After my upgrades, that car ran right around 195 degrees all the time, just like it should.

FWIW I love 928s, really are the "German Corvette" with significantly higher quality. But I will never own another one. Without question, the most expensive cars I have ever run...and I have a Ferrari in the garage!

If the cooling system is working properly and you've got the right combination of coolant, thermostat, fan-on cal and radiator, in my experience, ECT, even with the A/C on is not an issue

Amen. I have spent a lot of time working through cooling systems, both stock and upgraded, on a multitude of cars, both street and track driven. My own opinion is stock is usually best for almost all situations, as long as it's in optimal condition. Get the stock system right, and you won't have any problems. I live in Atlanta, as hot a humid a place as anywhere in the US. My own ZR-1, in summer traffic jams with the a/c on, will run a little warm until the fans come on. Then the temp drops back down exactly like it's supposed to. Get the radiator clean, run it like Hib says, and it should work well.

[Karl]

So is a 3 core overkill? S that ever decided in this thread?

I do not think a 3 row/core radiator is overkill. If I had more patience to modify the fan shroud and radiator mounts I would have used the Champion 3 row unit I have. But since all my a/c stuff is new and I did not want open a can of worms I did not want to take a chance of messing up modifying the lower radiator mounts while they are still in the car.

[secondchance]

I don't think it's simple as number of cores. Actual engine cooling seems would depend on number of variables - flow rate, core to fin heat transfer rate, fins to air heat transfer rate, at least.
As for the flow rate, too slow would result in inefficient coolant cooling and too fast would hamper core to fin heat transfer also resulting in inefficient cooling.
Main reason I opted for aftermarket radiator is because I had two OEM radiators fail (typically at 80,000 miles plus/minus) and, with minimal clearance between the fins, are prone to clogging with small particulates. Also, I am hoping dual core construction of Dewitt unit may improve core to fin heat transfer. We shall see...

[Bob Eyres]

Some early C4's had a pusher fan from the factory.
Pete

Pete, if that's true why not find a NOS one, or search the bone yards. C4's are all very similar, wouldn't it be a logical solution to add a GM engineered solution that already exists?

For what it's worth, i've got a Bee Cool radiator, a 160deg. Thermo., and a manual fan switch.
That seems to work well for me here in the sub-tropics.

I also used Evans Propylene Glycol coolan,t (100%), for about ten years too, but I've found that the green stuff and water actually cools a little better.

[WVZR-1]

Pete, if that's true why not find a NOS one, or search the bone yards. C4's are all very similar, wouldn't it be a logical solution to add a GM engineered solution that already exists?



All C4 Corvettes with "pusher fans" were '89 or earlier when the radiator was mounted "vertically" in the radiator supports. In '90 the radiator mounting was changed so there's NO OE "pusher" that would work for the '90+ arrangement.

[XfireZ51]

All C4 Corvettes with "pusher fans" were '89 or earlier when the radiator was mounted "vertically" in the radiator supports. In '90 the radiator mounting was changed so there's NO OE "pusher" that would work for the '90+ arrangement.

The 84 was a "sucker". I think the C4 went thru several changes in the orientation of radiators during its build.

[WVZR-1]

The 84 was a "sucker". I think the C4 went thru several changes in the orientation of radiators during its build.

ALL C4 Corvette primary fans are "pullers" - the only "pusher" fans are the secondary/auxiliary fans and then only those are in the '89 or earlier with the vertically mounted radiator. '90+ cars all have a pair of puller fans.

'84 was the only year that didn't offer the secondary/AUX fan. There's only 2 orientations, '84 - '89 and '90+.

[XfireZ51]

ALL C4 Corvette primary fans are "pullers" - the only "pusher" fans are the secondary/auxiliary fans and then only those are in the '89 or earlier with the vertically mounted radiator. '90+ cars all have a pair of puller fans.

'84 was the only year that didn't offer the secondary/AUX fan. There's only 2 orientations, '84 - '89 and '90+.

Yeah ok.

[Pete]

Pete, if that's true why not find a NOS one, or search the bone yards. C4's are all very similar, wouldn't it be a logical solution to add a GM engineered solution that already exists?

For what it's worth, i've got a Bee Cool radiator, a 160deg. Thermo., and a manual fan switch.
That seems to work well for me here in the sub-tropics.

I also used Evans Propylene Glycol coolan,t (100%), for about ten years too, but I've found that the green stuff and water actually cools a little better.


WVZR-1 explained it before i got to it.
I looked into it and it would not mount to the newer style radiator set up.
Because of the vertically mounted radiator and radiator supports.

An aftermarket 12" pusher should work just fine for the later years.

Pete

[WVZR-1]

It would seem that the air cleaner housing would interfere BUT if a person had the SLP 3 filter arrangement it might allow for an additional "pusher" to be mounted easily. Maybe not EASILY but I believe it would help!