Cooler Thermostats, Thermostat Modifications and Engine RPM

[Dynomite]

Debate This :D

Cooler Thermostats, Thermostat Modifications, Engine RPM, and Fans

Here is what I have found regarding LT5 Stant Thermostats.

1. You want to run the engine at coolant Temperatures of 180 deg as the design requirement...……...Running cooler Thermostats only lowers coolant temperatures when running coolant below 180 deg F (which is too cold for the LT5 engine). Once the 180 deg Thermostat and 160 deg Thermostat are fully open at 180 deg, Coolant flow is the same through each Thermostat with equal cooling as directly dependent on coolant flow.
2. Drilling Holes in Thermostats offers minimal (non effective) additional Coolant Flow...….A 1/8 inch diameter hole in the flange will only offer additional flow area of .0123 square inches. Which one such hole will increase the total flow area by .016 or 1.6% (three 1/8 inch diameter holes would increase the flow area by 4.7%). This thinking does not address the change in coefficient of Discharge of such small holes. The Stants tested would be fully open with a flow area of approximately .785 square inches at 185 deg F.
3. The Stant Thermostat Opens a bit less with age......…...Marc suggests a 15% deterioration in Full opening area of the Thermostat over time as the Thermostat ages.
4. The LT5 Water Pump Flow is proportional to Engine RPM. ......The LT5 Water Pump Flow rate is insufficient at RPMs less than 2,000 RPM for adequate Coolant flow at the higher Ambient Temperatures. Larger Aluminum Radiators DO compensate for inadequate Coolant Flow at low RPMs. Fans Turning on at 205 deg F do help considerably. And KEEP The Radiator, Oil Cooler, AC Condenser CLEAN.
5. Fan Air Flow is inadequate when the ZR-1 is not moving...…..This was noticed when the ZR-1 coolant decreased in Temperature when shifting from 6th to 5th at 65 mph (going from 1,500 to 2,200 rpm) but while not moving increasing the rpm from 750 to 2,000 had the opposite effect actually increasing coolant temperature.

And I was thinking the issue was solved wherein it is TWO issues (Fan air flow at low speeds and water pump coolant flow at low rpms).

In regard to Item #2 and #3 above...…..Compared to the normal aging of the thermostat of 15% over several years of use one would be much better off installing a NEW Stant Thermostat gaining 15% flow area as compared to drilling three 1/8 inch holes in an older Stant Thermostat only gaining 4.7% flow area.

See Post 120 - Thermostats, Fans, Radiators and Coolant Filling (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1584987828)

Post 286 - Cooler Thermostats, Thermostat Modifications, Engine RPM, and Fans (https://www.corvetteforum.com/forums/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-15.html#post1596384586)

[Hib Halverson]

Debate This :D

Cooler Thermostats, Thermostat Modifications and Engine RPM

Here is what I have found regarding LT5 Stant Thermostats.

1. You want to run the engine at coolant Temperatures of 180 deg as the design requirement...……...Running cooler Thermostats only lowers coolant temperatures when running coolant below 180 deg F (which is too cold for the LT5 engine). Once the 180 deg Thermostat and 160 deg Thermostat are fully open at 180 deg, Coolant flow is the same through each Thermostat with equal cooling as directly dependent on coolant flow.
Flow is only one variable which affects cooling. Others are: ability of the coolant to accept heat from the combustion chamber walls and the ability of the radiator to transfer heat to the atmosphere.
2. Drilling Holes in Thermostats offers minimal (non effective) additional Coolant Flow...….A 1/8 inch diameter hole in the flange will only offer additional flow area of .0123 square inches. Which one such hole will increase the total flow area by .016 or 1.6% (three 1/8 inch diameter holes would increase the flow area by 4.7%). This thinking does not address the change in coefficient of Discharge of such small holes. The Stants tested would be fully open with a flow area of approximately .785 square inches at 185 deg F.
Agreed. The practical value of "Drilling" 'stats is a myth.
The Stant Thermostat Opens a bit less with age......…...Marc suggests a 15% deterioration in Full opening area of the Thermostat over time as the Thermostat ages.
If Marc "suggests" that, barring any other test data, I'd sure be taking his suggestion as fact.
4. Lastly, The LT5 Water Pump Flow is proportional to Engine RPM. ......The LT5 Water Pump Flow rate is insufficient at RPMs less than 2,000 RPM for adequate Coolant flow at the higher Ambient Temperatures. Larger Aluminum Radiators DO compensate for inadequate Coolant Flow at low RPMs. Fans Turning on at 205 deg F do help considerably. And KEEP The Radiator, Oil Cooler, AC Condenser CLEAN.
The "bandwidth" of the water pump's flow is not wide enough. What GM should have done was give the LT5 an all-aluminum radiator and a higher system pressure. Then the coolant bypass could have been decreased which would have improved cooling at low engine speeds.

Now compared to the normal aging of the thermostat of 15% over several years of use one would be much better off installing a NEW Stant Thermostat gaining 15% flow area as compared to drilling three 1/8 inch holes in an older Stant Thermostat only gaining 4.7% flow area.
Well...duh!

See Post 120 - Thermostats, Fans, Radiators and Coolant Filling (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1584987828)

[Dynomite]

Flow is only one variable which affects cooling. Others are: ability of the coolant to accept heat from the combustion chamber walls and the ability of the radiator to transfer heat to the atmosphere. Yes......I agree with you on the other variables :thumbsup: but on this one variable of thinking a cooler thermostat will run the engine cooler at ALL temperatures is a myth since both the 160 deg thermostat and 180 deg thermostat function the same at engine temperatures over 185 deg F. (It will just take a bit longer to get there using the 160 deg Thermostat).



Agreed. The practical value of "Drilling" 'stats is a myth. Thank you for confirmation :thumbsup:



If Marc "suggests" that, barring any other test data, I'd sure be taking his suggestion as fact. Concur completely :cheers:

The "bandwidth" of the water pump's flow is not wide enough. What GM should have done was give the LT5 an all-aluminum radiator and a higher system pressure. Then the coolant bypass could have been decreased which would have improved cooling at low engine speeds. Yes again but the engine rpm up to 8,000 and the resulting Head Loss in plastic radiators were an issue.....thanks for confirmation again :thumbsup:





Well...duh! I would not use the word "duh" as it may be obvious to some but not so obvious to ALL :p



See Post 120 - Thermostats, Fans, Radiators and Coolant Filling (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1584987828)



Thank You Hib......:cheers::cheers:



Keep the mice, leaves, plastic bags out of the Radiator area between Radiator, Oil Cooler, and AC Condenser using a debree screen with maximum 1/4 inch spacings. Do install a new Stant 180 deg Thermostat to make sure of maximum functionality of the Thermostat temperature control.



Also......Do install a Marc Haibeck Chip lowering Cooling Fan Operation to 205 deg ON and 200 deg OFF.



And many in HOT climates DO install Fluidyne, Dewitt or other brand Aluminunm multi core Radiators for greater cooling at the higher Engine RPMs.



(Run in sixth gear at 55 mph for a while on a relatively warm day, then shift to fifth and watch the Temperature gage drop) :thumbsup:

See Post 120 - Thermostats, Fans, Radiators and Coolant Filling (http://forums.corvetteforum.com/c4-zr-1-discussion/3005470-tech-info-lt5-modifications-rebuild-tricks-500-hp-6.html#post1584987828)

[5ABI VT]

What bothers me most is if the oem stat is losing 15% opening area due to age. There aren’t any thermostats available so that’s why I was looking into options for lower stats. By the sounds of it 170 is what I would want since it wouldn’t actually keep temps at 170 but more like 180-185 which seems to be the temps everyone says the LT5 likes or is tuned for.

There are several cars out there that use thermostat housings similar to the ZR-1. I’m hoping I can find one similar to the LT5 and has all the fittings for the heater hoses etc that will house a widely available thermostat with a choice of temps. I plan to run an electric wp I’m not a fan of the bypass bandaid solution to prevent exploding radiators.

[HAWAIIZR-1]

Hey Cliff,

No debate here and I pretty much agree with your findings. My car started running in the mid 230s so I tried to clean out the radiator. No debris, but it had a bunch of sand in fins after some banging on it. That did not help so I replaced original radiator 31K miles on a 95 with DeWitts two core (love the fit and ease of installation) AC Delco 180 (did not drill holes) thermostat and Jerry’s silicone hoses/clamps while I was at it. Marc’s chip already installed.

To my surprise, the thermostat that came out from precious owner was a AC Delco 180 with eight 1/8” holes drilled. [emoji33]. I’ll send it to you if you want it....LOL.

In high 60s degree weather a few weeks ago, it ran in high 190s in various traffic conditions and got to 208 highest in stop and go traffic. I am very pleased and comfortable with that. I am mostly curious how it will do in the summer heat next year. You probably remember I consulted with you about this while I was gathering the parts and decided drilling holes was a no go. Thanks!


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[Dynomite]

Hi Craig.....You can hang on to the "holy" thermostat :D

I have found my coolant stays in the 190s and maybe up around 208 like yours on the warmer days as long as I keep the rpms above 2,000 while driving. Keeping the engine rpm above 2,000 at idle actually will raise the coolant temperature unless you have installed greater flow rate fans. It is amazing to watch that temperature gauge go up and down at 65 mph as I shift back and forth between 5th and 6th.

Have a great Christmas Craig :thumbsup:

[HAWAIIZR-1]

Hi Craig.....You can hang on to the "holy" thermostat :D



I have found my coolant stays in the 190s and maybe up around 208 like yours on the warmer days as long as I keep the rpms above 2,000. It is amazing to watch that temperature gauge go up and down at 65 mph as I shift back and forth between 5th and 6th.



Have a great Christmas Craig :thumbsup:


Hey Cliff,

Ha, ha.....I should have just popped it in the mail for your trophy case...LOL!!!

Nice to hear the confirmation of similar temps. I’ll remember if stuck in traffic (which happens a lot here in Japan) to keep those revs up over 2K rpm if it gets too high. On the freeway it really cools down nicely. I have a different front bumper and a BMAD behind it so hard to compare to stock.

Take care and have a Merry Christmas to you too.

Aloha,
Craig



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[dredgeguy]

Wazoo replaced my plugged original radiator last year and put in a new DeWitts but I still saw the temps in the 235-240 range when I hit DC/Northern VA traffic. I was crawling along for almost 2 hours with fuel on reserve so keeping RPM's up was not an option. Now looking at possibility of DeWitts new fan box with two 11" Spal electric fans. Traffic is not getting any better and very stressful watching the temp gauge going up when stopped and then back down to 190-195 when moving.

[lfalzarano]

Did you install one of Marc’s chips that turn on the fans sooner?


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[dredgeguy]

Sure did, one of the first things I did 5 years ago along with new injectors.

[Ccmano]

While I agree with all that has been discussed here (even though I have experimented with the 1/8 hole), this discussion focuses purely on the keeping the engine cool in high temp conditions and the limitations of the LT5 cooling system.

There is a flip side to this conversation. The thermostat also serves to keep the engine temps up in cold ambient conditions. Unlike the old carbureted engines, the LT5 requires a minimum operational temp for optimal performance. This was no doubt done mainly for emissions reasons. (Engine lubrication and wear are also considations) Some still think that putting in the coldest thermostat will make the engine run colder and thereby perform better. In the case of the LT5 and likely most modern engines you can put in too cold a thermostat and actually hurt the performance of the engine. That window from the standard thermostat to one that is too cold is actually quite small. For optimum performance the motor needs to get to ~ 147F in order for ECM to enter Closed Loop. It needs to be at 176F in order for the LEARN mode to be active. Otherwise the ECM doesn't modify the Long Term Fuel Trim. These values are not adjustable in tune to my knowledge. Because of this the coldest thermostat for the system will optimally tolerate is about 170.

Although done for largely lubrication reasons, this is why, for example, in the colder climates you will often see trucks with radiator blockers. They are blocking the air flow to keep their engines warmer in the cold.

While most of us never operate our cars in very cold conditions, driving in even 40 degree ambient temps will result in coolant temps below 176 with a 170 degree or colder thermostat. I assume this is some of the reason Haibeck recommends (and sells) only going to a 170 degree thermostat.

I probably missed something here and will no doubt be corrected. But it is important to understand there is more to a thermostat in the system than the warm up of the engine at its start.

Let the debate continue.
H
:cheers:

[mhobtr]

Optimum engine design clearances are set for operation at the engine design operating temperature.

Engine wear is accelerated when the engine is operated below or above the design parameters. When too cold, bearing clearances will be tighter, which increases friction. When too hot pistons and other components can expand too far. If you have ever seen a collapsed piston from a engine that overheated, you know what I mean.

In the sixties, thermostats were typically 165 or 180 degrees. I used to swap my 180's for 165's every spring and swap back in the fall. Radiator and cooling system designs were not as sophisticated then and, living down south, the summer temps can be brutal on an engine. I know, I know, the thermostat sets the minimum operating temp and should have no further impact once fully opened, but that extra 15 degrees helped in many instances back then

My first catalytic converter car, with a 195 degree thermostat, was a 70 something Chevy with a small block. It was the first new car I had ever owned and I changed the oil religiously at 6,000 mile intervals as stated in the manual. At about 65,000 mile it started smoking and by 75,000 I had to tear it down for new rings and valve guides. I could not believe what I found when I pulled the valve covers. The oil had burned and left crystallized deposits which looked and felt like foundry sand on top of the head! Lifter valley was full of that junk also. I was devastated that I had let my engine get that way so I set out to determine what went wrong.

First thing I found was that the oils were not formulated for the higher temperatures and were breaking down. As this became more widely known, the practice of 3,000 mile oil changes became popular. Oils today are designed for the higher temps but I don't worry about it because I use nothing but Mobil 1 in all of my vehicles and it does not break down unless really abused.

Next, I learned that the 195 thermostats were necessary for proper catalytic converter operation but that the engine design parameters had not been revised for proper clearances at the higher temp. They were still optimum for 180 degrees. Mid seventies engines were notorious for early wear problems and most of us attributed it to the car manufacturers building crap cars with planned obsolescence so they could sell more cars.

By the mid eighties, oil formulations were catching up and engine clearances were redesigned for proper operation at higher temps.

Us old farts had a hard time buying into the 195 degree stats and there was a big market for 180 degree thermostat and modified chip sets. My 1993 Corvette, which I bought with 8K miles, had a 180 degree stat and chip proudly installed by the original owner. Worked fine until one day the chip died and left me stranded on the side of the road, Pulled it and the 180 and lived happily until I traded it for a '99.

It may not be a big deal to run a lower degree thermostat in an LT5, especially if you don't drive in cooler climates, but it was designed from scratch for a 195,.

[tpepmeie]

For optimum performance the motor needs to get to ~ 147F in order for ECM to enter Closed Loop. It needs to be at 176F in order for the LEARN mode to be active. Otherwise the ECM doesn't modify the Long Term Fuel Trim. These values are not adjustable in tune to my knowledge.

Both are adjustable in the calibration. But in different ways.
Closed Loop control is enabled at 47.75C, so the INTs will start to correct at this temp.

BLM learning is enabled at 81.50C (178.7F). You can lower this value in the calibration.

However the system will only learn when the commanded F/A ratio is 1.00. In other words, if there is any enrichment applied (e.g., coolant temp enrichment), the motor will not enter learn mode. You can look at the factory calibration and see that there is enrichment applied up to 68C (154.4F).

[HAWAIIZR-1]

Wazoo replaced my plugged original radiator last year and put in a new DeWitts but I still saw the temps in the 235-240 range when I hit DC/Northern VA traffic. I was crawling along for almost 2 hours with fuel on reserve so keeping RPM's up was not an option. Now looking at possibility of DeWitts new fan box with two 11" Spal electric fans. Traffic is not getting any better and very stressful watching the temp gauge going up when stopped and then back down to 190-195 when moving.


Hey Charlie,

Sorry to hear the DeWitts wasn’t enough to address your issue. I was thinking the same about the fans upgrade too if I find it’s too high for comfort in traffic. I think I remember Daryll mention he has the upgrade and it works very well in Arizona heat. Best wishes!



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[dredgeguy]

Thanks Craig,
It is not often that I hit this kind of traffic but in our area it is getting worse by the day. Hitting high temps will cause head gasket failure over time and that is one thing I want to avoid. Car has 92,000 miles on it, I enjoy it and drive it every chance I can. The DeWitts was a great improvement but cannot overcome the issue of idling in traffic when it is 95 degrees outside.

[secondchance]

Thanks Craig,
It is not often that I hit this kind of traffic but in our area it is getting worse by the day. Hitting high temps will cause head gasket failure over time and that is one thing I want to avoid. Car has 92,000 miles on it, I enjoy it and drive it every chance I can. The DeWitts was a great improvement but cannot overcome the issue of idling in traffic when it is 95 degrees outside.

How long were you idling in traffic? I have same set up and even with stroked, high compression, I never went over 220. Are you estimating coolant temp based on analog gauge? Or, does 92 have digital readout?
One difference is that I have one 1/8" hole on thermostat flange.

[dredgeguy]

My 92 has both analog and digital readout. When we put in the new radiator and new thermostat you put the hole in the thermostat flange so all is the same as your set up. I was on the way back from Dempsey's and got stuck in traffic on 495 for almost 2 hours.

[secondchance]

My 92 has both analog and digital readout. When we put in the new radiator and new thermostat you put the hole in the thermostat flange so all is the same as your set up. I was on the way back from Dempsey's and got stuck in traffic on 495 for almost 2 hours.

If temp rise to 235 plus occurred in 2 hrs, I would say only way to avoid the same probably is with higher capacity fans.

[Dynomite]

If temp rise to 235 plus occurred in 2 hrs, I would say only way to avoid the same probably is with higher capacity fans.

Concur :thumbsup:

Yes......just did some tests at 50 deg F ambient.
Fans on at 205 deg F and off at 200 deg F.

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.
Will check fans and air path again tomorrow just to make sure.

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.

And I was thinking the issue was solved wherein it is TWO issues (Fan air flow at low speeds and water pump coolant flow at low rpms) :p

[Mystic ZR-1]

Would “Waterwetter” help?
Allegedly helps with heat transfer?

[HAWAIIZR-1]

Thanks Craig,

It is not often that I hit this kind of traffic but in our area it is getting worse by the day. Hitting high temps will cause head gasket failure over time and that is one thing I want to avoid. Car has 92,000 miles on it, I enjoy it and drive it every chance I can. The DeWitts was a great improvement but cannot overcome the issue of idling in traffic when it is 95 degrees outside.


I hear you on that Charlie! We get some really gridlocked situations over here. Mostly I tour on the Harley for that reason and can split lanes all the way. A few weekends ago it said 4 hours on google maps to go what would take two or less. Traffic not moving at all and backed up for about 10 miles. I really want to drive the Z more often so trying to get it right for all conditions and making it reliable. I think I’m heading towards the DeWitts fan upgrade either way.



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[Dynomite]

I think I’m heading towards the DeWitts fan upgrade either way.

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Tell me more about the DeWitts Fan Upgrade......Is this what Goldcylon was up to?
Goldcylon.....where are you :p

[Ccmano]

Tell me more about the DeWitts Fan Upgrade......Is this what Goldcylon was up to?
Goldcylon.....where are you :p

I seem to remember Darryl (Goldcylon) posting about a fan upgrade as well.
:happy1:

Might be this thread, see post #29
http://www.zr1.net/forum/showthread.php?t=20756&highlight=Cooling+fan&page=3

H
:cheers:

[Dynomite]

I seem to remember Darryl (Goldcylon) posting about a fan upgrade as well.
:happy1:

Might be this thread, see post #29
http://www.zr1.net/forum/showthread.php?t=20756&highlight=Cooling+fan&page=3

H
:cheers:


Yes...….that be it.....Dewitt Radiator and Spal Fans (http://www.zr1.net/forum/showthread.php?p=178210#post178210)

[HAWAIIZR-1]

Tell me more about the DeWitts Fan Upgrade......Is this what Goldcylon was up to?

Goldcylon.....where are you :p



Cliff,

Ha, ha....you were probably the OP on all those posts that GC replied to about cooling...lol.

I’m kind of sold on the fact I want the Spal fan upgrade. Do I need it? Probably not, but more than I need to drill holes or mess with lower range thermostats. It makes sense to move that amount of air while sitting still and not have to rev the motor to keep temps down in heat and traffic. Not for everyone, but my situation and Charlie’s once in awhile is a nice mod to have for those that really want to drive and enjoy these cars in all weather and traffic conditions.

It seems like a sound investment to me. Heck, I burn more money on other foolish things than this:

https://www.dewitts.com/collections/spal-fans/products/c4-fan-upgrade


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[secondchance]

Would “Waterwetter” help?
Allegedly helps with heat transfer?

Maybe. However, I got burned one too many times by products seemingly too good to be true. I am leaning towards more mechanical solution.

[rkreigh]

in the summer run a bit higher percentage of watter (or pure watter with additive). the suffocant watter wetter products do work better this way too and can buy you a bit cooler running but the real problem is that with a thicker heavy duty radiator the stock fans aren't up to snuff


I got at carlisle a while back some aftermarket dewitts spal fans that are much stronger


the bottom breather design sucks hot air off the pavement which doesn't help when the AC condensor gets hot


after the car suffers too many trips over 240 the hg will call it quits from being crushed from the alum expansion and not recovering well and it starts to weep (ask me how I know)


My problems started when I blew a fancy samco rad hose. Lucky it was up top and I was able to pull over right away when I saw the "plume"



but getting the car burped and full of coolant took it hot, and I had to wait for it to cool down to get the car full of coolant. About 5 months later, my HG called it quits and I had a nice fountain coming out of $6 cyl


it also "scalloped" the bottom of that liner (no bueno) so it's now a complete rebuild. Take care of those HG, and the car will orbit the moon. Or suffer ye a similar fate. Hoses and hg and cooling system on high hp cars can be an achillies heal.

[Dynomite]

I got at carlisle a while back some aftermarket dewitts spal fans that are much stronger

the bottom breather design sucks hot air off the pavement which doesn't help when the AC condensor gets hot



I will check this our further today just to see if there is a chance the Stock Fans (Motors and Fans) can be switched out for Spal Motors and Fans. This would eliminate any modifications of the Fan Housing. And I am not sure about the Stock Fan Electrical Connector vrs the Spal Connector ……..But I am sure that is way too much to ask for :D

There might be other Fans that can be purchased (Fan and Motor Only) that will solve the issue as well. Just did an Ebay search "Electrical Engine Cooling Fans" and got 4,000 results :D

Exactly how much more air flow are we talking about with Spal Fans?
Goldcylon…….I think you did this Spal Fan Switch out and said..... "Plenty of air movement".

This is definitely worth exploring but kind of pricy solution for a coolant issue in traffic only and only on 110+ deg days. Coolant heating issues cruising is not an issue as long as we use 5th gear at speeds less than 80 mph and use 6th when cruising 80 and over on the interstate :cheers:

[secondchance]

I will check this our further today just to see if there is a chance the Stock Fans (Motors and Fans) can be switched out for Spal Motors and Fans. This would eliminate any modifications of the Fan Housing.

Wishful thinking Cliff. Eyeballing Span fan assembly and OEM fan/fan shroud, I don't think it will be simple remove OEM fan followed by re-install Spal fans.

Twin Spal fan claimed air movement is 2,760 CFM, I believe.

I think I will be looking into this also before June 2019. I've been getting a bit bored.:cheers:

[dredgeguy]

I have 4.10 gears so driving in 5th or 6th during the summer is not the issue or any concern of mine. It is stop and go traffic (mostly stopped) when outside temps are 95+. During summer here in the Mid-Atlantic we have many of those hot and humid summer days and for sure the traffic around DC/northern VA is stop and go all day long. Just would be nice to be able to relax if stuck in traffic rather than feeling my blood pressure going up with the coolant temps.

[HAWAIIZR-1]

I will check this our further today just to see if there is a chance the Stock Fans (Motors and Fans) can be switched out for Spal Motors and Fans. This would eliminate any modifications of the Fan Housing. And I am not sure about the Stock Fan Electrical Connector vrs the Spal Connector ……..But I am sure that is way too much to ask for :D



There might be other Fans that can be purchased (Fan and Motor Only) that will solve the issue as well. Just did an Ebay search "Electrical Engine Cooling Fans" and got 4,000 results :D



Exactly how much more air flow are we talking about with Spal Fans?

Goldcylon…….I think you did this Spal Fan Switch out and said..... "Plenty of air movement".



This is definitely worth exploring but kind of pricy solution for a coolant issue in traffic only and only on 110+ deg days. Coolant heating issues cruising is not an issue as long as we use 5th gear at speeds less than 80 mph and use 6th when cruising 80 and over on the interstate :cheers:


Cliff,

With your money there should be no concern to upgrade; just do one Z; you don’t have to upgrade all 5 Zs?...,LOL.

As mentioned by the WAZOO brothers it’s the piece of mind to meet any conditions. I believe GC also mentions more room to work as the housing is not cumbersome like the factory unit. Did you see the size of those fans? I like it!!! That’ll move some air! It looks like plug and play with connectors, but it does mention and so does GC about relocating the AC accumulator can. I do want to know what is involved with that. I’ll call them if no answer here. My time zone difference makes calling a challenge.



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[Dynomite]

I believe GC also mentions more room to work as the housing is not cumbersome like the factory unit. Did you see the size of those fans? I like it!!! That’ll move some air!

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Daryll says the Fans roar with a pitch that you normally hear on the newer cars referring to the New Fan Installation :thumbsup::thumbsup:

I can hardly hear the stock fans which kind of purrrrrrr definitely not a roar :D
I was not so sure they were on as I was feeling for air movement...…..but they were on when I stuck my fingers in them :sign10:

He (GC) has been off for a week but I am sure he will help us out when he gets back :handshak:

Wishful thinking Cliff. Eyeballing Span fan assembly and OEM fan/fan shroud, I don't think it will be simple remove OEM fan followed by re-install Spal fans.

Twin Spal fan claimed air movement is 2,760 CFM, I believe.

I think I will be looking into this also before June 2019. I've been getting a bit bored.:cheers:

I concur after a short look...………..Now that is a clue (CFM). I wonder what the CFM is with the Stock Coolant Fans???

Just would be nice to be able to relax if stuck in traffic rather than feeling my blood pressure going up with the coolant temps.
I think we are on to something with the lack of Stock Fan CFM which is required in stop and go traffic in addition to keeping the rpm above 2,000 for adequate coolant flow. But as I experimented with the other day, idling at 2,000 rpm even on a 50 deg day ups the coolant temperature rather than lowers coolant temperature because of lack of Fan Air Flow through the Radiator. I removed more heat from the engine which heated up the radiator which sent the hot coolant right back into the engine :D

We have to do both......remove more heat from the engine and remove more heat from the radiator in stop and go traffic (on HOT days) at low engine rpms.
Now if we could increase Fan rpm as well as engine rpm we would not have an issue in stop and go traffic.

At low rpms (when not moving) we have inadequate coolant flow AND inadequate air flow through the Radiator/Oil Cooler/Condenser.

[HAWAIIZR-1]

Daryll says the Fans roar with a pitch that you normally hear on the newer cars referring to the New Fan Installation :thumbsup::thumbsup:



I can hardly hear the stock fans which kind of purrrrrrr definitely not a roar :D

I was not so sure they were on as I was feeling for air movement...…..but they were on when I stuck my fingers in them :sign10:



He (GC) has been off for a week but I am sure he will help us out when he gets back :handshak:


Cliff,
Our secondary air injection pump pushes more and makes more sound....LOL!!!



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[lfalzarano]

There are new fan blade replacements they provide a 20 percent increase in air flow compared to their conventional counterparts.

https://www.corvetteonline.com/features/pri-coverage/pri-2018-cooling-off-with-flex-a-lites-flex-wave-electric-fans/


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[Dynomite]

There are new fan blade replacements they provide a 20 percent increase in air flow compared to their conventional counterparts.

https://www.corvetteonline.com/features/pri-coverage/pri-2018-cooling-off-with-flex-a-lites-flex-wave-electric-fans/


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Available Feb 2019...…...There’s no change in the motor or shroud.
These fans come in 12″, 14″, and 16″ sizes.

I am trying to figure out if you buy just the blades or motor and blades but appears you use existing motor?

I am looking for a Bigger Motor I can adapt to our existing Fan Shroud that would make the fans "Roar" as GC suggests :cheers:

[Jagdpanzer]

Here is the Dewitt C4 Spall fan kit laid out on the pool table next to C4 OEM fan
8721


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[Dynomite]

Here is the Dewitt C4 Spall fan kit laid out on the pool table next to C4 OEM fan
8721


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Phil.....did you install that Fan Kit? If so......How does the Air Flow compare to Stock Fans? I think I read 2760 cfm for the two Spall Fans??

I wonder what the cfm is for the two Stock Fans?

It seems I could install those Spall Fans into the Stock Fan Frame with some work but could be done???

Are the electrical connectors the same?


http://www.zr1.net/forum/picture.php?albumid=387&pictureid=3857

[Jagdpanzer]

Going in with the 427 motor this winter. Doubt the stock electric motors are stout enough to swing the Spall fan blades at the correct RPM


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[Jagdpanzer]

Phil.....did you install that Fan Kit? If so......How does the Air Flow compare to Stock Fans? I think I read 2760 cfm for the two Spall Fans??



I wonder what the cfm is for the two Stock Fans?



It seems I could install those Spall Fans into the Stock Fan Frame with some work but could be done???



Are the electrical connectors the same?





http://www.zr1.net/forum/picture.php?albumid=387&pictureid=3857







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[Dynomite]

Going in with the 427 motor this winter. Doubt the stock electric motors are stout enough to swing the Spall fan blades at the correct RPM


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I meant install the Spall Motors and Fans into the Stock Frame ;)

If I read this correctly, I could install two of these 1,600 cfm Spall 11" Fans and end up with 3,200 cfm :thumbsup:
Single 11" Spal Fans 30102800 on Ebay (1,600 cfm) (https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=Spal+Fans+30102800&_sacat=0)

[lfalzarano]

The impression is that these new fan blades replace your existing stock blades using the existing shroud and motor.


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[Dynomite]

The impression is that these new fan blades replace your existing stock blades using the existing shroud and motor.


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Flex A Lite yes...….Fan blades only.

Spal Fan Kit...…..no......the kit comes with new shroud, motor and fan blades.

Spal Fans from Summit Racing (2,700 cfm) (https://www.summitracing.com/parts/spu-ix-30102052/overview/)

I am thinking I might want to try and use existing shroud installing new Spal motors and fans.

If I read this correctly, I could install two of these 1,600 cfm Spall 11" Fans and end up with 3,200 cfm :thumbsup:
Single 11" Spal Fans 30102800 on Ebay (1,600 cfm) (https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=Spal+Fans+30102800&_sacat=0)

[Dynomite]

I've used these for 5 years. Modded daily drivers in AZ heat when the freeway hits 128/135 its a must

Exactly which fans or fan shroud did you install and how did you install?
Did you have to modify anything during the installation?

Spal Fans from Summit Racing (2,700 cfm) (https://www.summitracing.com/parts/spu-ix-30102052/overview/)

Single 11" Spal Fans 30102800 on Ebay (1,600 cfm) (https://www.ebay.com/sch/i.html?_from=R40&_trksid=m570.l1313&_nkw=Spal+Fans+30102800&_sacat=0)

Did you use different electrical connectors (how did you connect fans to stock electrical connector)?

Do both your fans come on at 205 deg and off at 200 deg (Haibeck Chip)?