Mostmint Racing 1989 Corvette Build
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
It is an interesting thought. My thought is that it's a net loss for cooling effectiveness, at altitude; You're right that there is less fuel injected, and there is less air flow over the cooling surfaces....but friction remains the same with regard to heat generation. Who knows though? An engineer does, but I'm not an engineer. you're also right that I live at ~7000', but our track is in Tooele/Grantsville, which is at about 4500'elevation.
My LT1 is box stock. It has a Dewitts "small" radiator, but I tracked it before and after swapping and the diff was negligible to nothing.
My LT1 is box stock. It has a Dewitts "small" radiator, but I tracked it before and after swapping and the diff was negligible to nothing.
Thread Starter
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Joined: Dec 2018
Posts: 92
Likes: 13
From: Wadsworth, Ohio
A PS cooler was one of the first things I did when I started tracking. When I removed the stock oil "cooler" my oil temps dropped fifty degrees. It's more of an oil warmer! Stock brakes hmm it's possible but unlikely they will be okay. They didn't work out well on the tracks I go to. I switched to C5 brakes partly because the rotors have been half the cost so there's that aspect too. The auto needs a large cooler and any other help you can give it.
The price of replacements is a factor which I will consider - thanks for that info.
Thread Starter
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Joined: Dec 2018
Posts: 92
Likes: 13
From: Wadsworth, Ohio
My '90 had factory coolers and would constantly see 300+ oil temps and 230+ water at a track day within a 20 minute session. No offense, but if you're not getting there in your LT1 you probably are not driving it hard enough. C4 cooling is terrible. Im not at all surprised it got that hot at 30° out. It wasnt until I added an aftermarket oil cooler that water stayed below 230° and oil below 280° during a 20min session. Now that its a race car I have an even bigger oil cooler and I can run all day at 200° water and 230-250° oil.
Thanks for the operating temp info - which is confirming to me this is not some anomaly related to my engine.
Race Director
Joined: Jun 2004
Posts: 13,966
Likes: 710
From: WI
My '88 has been 2950 race weight with 365 rwhp, NASA time trial. I'm not serious about going to nationals and that sort of thing. I just like having fun local, Road America is close.
Thread Starter
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Joined: Dec 2018
Posts: 92
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From: Wadsworth, Ohio
Thanks. I'm planning to be at 2800 or less (minus fuel and driver) with 240 rwhp and on UTQG 200 tires - so less weight to stop and less speed. Entirely possible I will need the C5 upgrade, but my demands on the brakes should be less than yours.
Oil Producer
Joined: Apr 2014
Posts: 9,380
Likes: 2,744
another consideration is that the powerstop “trackday” kit is very affordable and as ling as you dont mind brake dust they worked excellent on my 86.
fwiw, 22deg C, stock 86 4+3, with kc4 heat exchanger, 2hrs straight hard driving, max oil temp was 266f and max coolant temp was 230f.
if your coolant was way lower than your oil, the kc4 is going to help alot.
also my radiator is 100% stock, i spent a considerable amount of time cleaning and straightening the fins on both the condenser and radiator. i did a full system flush using vinegar. I have iron heads.
mint, the 91 came stock with the ps cooler....for the z51. it mounts on the front face of the k member.
Le Mans Master
Joined: Oct 2007
Posts: 9,702
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From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
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Like Andrew mentioned, the factory cooler just circulates coolant around the oil filter adapter and probably does more heating the oil than cooling. I still wouldn't be surprised by your numbers though, especially if you're running lean. That will make more heat than you think.
Oil Producer
Joined: Apr 2014
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i know u guys have waaaay more experience on the track than i do, but i have a hard time understanding how the kc4 could ever heat the oil if the oil temps are 300 and the coolant is 230. doesnt heat flow from high to low?
i found it worked great and i have always wondered why there was do much poopooing of the kc4. i do think an air to oil cooler would be much better! in mints situation that takes points.
i found it worked great and i have always wondered why there was do much poopooing of the kc4. i do think an air to oil cooler would be much better! in mints situation that takes points.
Last edited by VikingTrad3r; Nov 5, 2019 at 09:13 AM.
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Le Mans Master
Joined: Oct 2007
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From: Akron Ohio
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The more heat you dump into the coolant the less effective it becomes. They will both slowly reach an equilibrium and be the same temp (after awhile), but you see the effects in less than 15 minutes on track.
Thread Starter
Advanced
Joined: Dec 2018
Posts: 92
Likes: 13
From: Wadsworth, Ohio
Like Andrew mentioned, the factory cooler just circulates coolant around the oil filter adapter and probably does more heating the oil than cooling. I still wouldn't be surprised by your numbers though, especially if you're running lean. That will make more heat than you think.
I am definitely taking the points for an external oil cooler. I put one on my 1.9 liter Saturn engine, it is worth the points. At this point it might be as big as the radiator, but I will have one
Oil Producer
Joined: Apr 2014
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Safety Car
Joined: Sep 2001
Posts: 4,161
Likes: 554
From: Glenbeulah Wi
i know u guys have waaaay more experience on the track than i do, but i have a hard time understanding how the kc4 could ever heat the oil if the oil temps are 300 and the coolant is 230. doesnt heat flow from high to low?
i found it worked great and i have always wondered why there was do much poopooing of the kc4. i do think an air to oil cooler would be much better! in mints situation that takes points.
i found it worked great and i have always wondered why there was do much poopooing of the kc4. i do think an air to oil cooler would be much better! in mints situation that takes points.
When the engine is cold the cooler may warm up the oil as long as the oil is cooler then the water but as soon as oil temp exceeds water temp the cooler will start cooling the oil.
One other point, factory lt1 thermostat is a 180 not 210 as mentioned.
Thread Starter
Advanced
Joined: Dec 2018
Posts: 92
Likes: 13
From: Wadsworth, Ohio
Power steering cooler questions:
1) This feature came in 1989 as part of the Z51 package correct?
2) I believe this was standard on 1991. Are there other years that it was a standard feature, and what RPO did it come under when it was optional
2) Looks like these were first offered in 1987, and went through several changes throughout the years. Is the bracket that supports the cooler the same from 1987-1996? I could make one, but it won't cost me any points if I use the factory bracket, so I would like to know which ones will fit my 89.
3) What are the approximate dimensions of this cooler?
4) anyone ever replace a stock cooler with an aftermarket? Any thoughts on this would be helpful. I don't think I need a larger one I just want to keep the costs down and not use 30 year old parts if possible
1) This feature came in 1989 as part of the Z51 package correct?
2) I believe this was standard on 1991. Are there other years that it was a standard feature, and what RPO did it come under when it was optional
2) Looks like these were first offered in 1987, and went through several changes throughout the years. Is the bracket that supports the cooler the same from 1987-1996? I could make one, but it won't cost me any points if I use the factory bracket, so I would like to know which ones will fit my 89.
3) What are the approximate dimensions of this cooler?
4) anyone ever replace a stock cooler with an aftermarket? Any thoughts on this would be helpful. I don't think I need a larger one I just want to keep the costs down and not use 30 year old parts if possible
Team Owner
Joined: Aug 2004
Posts: 21,543
Likes: 3,216
From: Park City Utah
It won't heat the oil as long as the oil temperature is higher then the water temperature. The water that exit's the radiator is as cool as it is going to be, that water is pumped into the block and cools the oil. The water then flows through the block and heads picking up heat and gets discharge into the radiator. The temp sensor for the gauge is in the heads and will read higher temp them the water in the block at the cooler.
When the engine is cold the cooler may warm up the oil as long as the oil is cooler then the water but as soon as oil temp exceeds water temp the cooler will start cooling the oil.
One other point, factory lt1 thermostat is a 180 not 210 as mentioned.
When the engine is cold the cooler may warm up the oil as long as the oil is cooler then the water but as soon as oil temp exceeds water temp the cooler will start cooling the oil.
One other point, factory lt1 thermostat is a 180 not 210 as mentioned.
If the oil is ~300 and coolant is ~230 as has been discussed earlier in the thread, then it's not at equilibrium and the water is most definitely cooling the oil.
Le Mans Master
Joined: Oct 2007
Posts: 9,702
Likes: 3,472
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
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I never said it wasn't cooling at those temps. Still cooling, yes. Effectively, no.
A stand alone oil cooler in front of the radiator will be much more effective.
A stand alone oil cooler in front of the radiator will be much more effective.
Le Mans Master
Joined: Oct 2007
Posts: 9,702
Likes: 3,472
From: Akron Ohio
2025 Corvette of the Year Finalist - Modified
2024 C5 of the Year Winner - Modified
2023 C5 of the Year Finalist - Modified
2022 C5 of the Year Finalist - Modified
St. Jude Donor '09-'10-'11
Power steering cooler questions:
1) This feature came in 1989 as part of the Z51 package correct?
2) I believe this was standard on 1991. Are there other years that it was a standard feature, and what RPO did it come under when it was optional
2) Looks like these were first offered in 1987, and went through several changes throughout the years. Is the bracket that supports the cooler the same from 1987-1996? I could make one, but it won't cost me any points if I use the factory bracket, so I would like to know which ones will fit my 89.
3) What are the approximate dimensions of this cooler?
4) anyone ever replace a stock cooler with an aftermarket? Any thoughts on this would be helpful. I don't think I need a larger one I just want to keep the costs down and not use 30 year old parts if possible
1) This feature came in 1989 as part of the Z51 package correct?
2) I believe this was standard on 1991. Are there other years that it was a standard feature, and what RPO did it come under when it was optional
2) Looks like these were first offered in 1987, and went through several changes throughout the years. Is the bracket that supports the cooler the same from 1987-1996? I could make one, but it won't cost me any points if I use the factory bracket, so I would like to know which ones will fit my 89.
3) What are the approximate dimensions of this cooler?
4) anyone ever replace a stock cooler with an aftermarket? Any thoughts on this would be helpful. I don't think I need a larger one I just want to keep the costs down and not use 30 year old parts if possible