Guys: Need some help with some cooling problems I’m having. I’ll start with my original set up, then how I changed it and the issues it created, then some possible solutions and see what you all think…

Original setup
2002 Z06
Older A&A Corvette D1SC Supercharger & Intercooler set up with the radiator slightly layed down
Forged Engine & Internals
Stock radiator w/ only distilled water and Water Wetter
Stock fan shroud and spal fans
Still have A/C
Car producing around 650 & 560 at the rear wheels @ 7 lbs of boost
On a 85 degree day, I saw temps of about 185 while doing around 70 mph with A/C off (not bad at all)

So… I get the bug to put the car on Heartland Park’s (Topeka, KS) 2.5 mile road course… he’re the prep I did to help with cooling issues I saw coming my way…

Installed a DeWitts Direct Fit radiator which is over twice as thick as the stock radiator (w/o the oil cooler, P/N: A97M) and a modified stock fan shroud with spal fans producing 3200 CFM (Also from DeWitts, P/N: SP015)
Still used just water and Water Wetter
Opened up the front w/ a Halltech Tunnel Port (opens the area where the lisence plate goes)
On a 90 degree day, I saw temps of about 210 doing the same 70 mph also with A/C off

After this I shored up the areas around the radiator that air could pass by… fabbed some aluminum to keep air from going past the sides, top, and bottom, and even angled that plastic air dam up at a 45 degree angle to force air up into the radiator, A/C, and intercooler. Temps were better after this, but still not as good as cool as with the stock radiator. Why?!?

When I tracked the car at Heartland Park in a 2 day HPDE, I ran it hard, but probably only 80% of its capability and to the dismay of my instructors, I ran the heater at full blast any time I was on the track. It was 98-103 degrees at any time, and I saw temps of 243 coolant and 270 for oil. Two of my instructors w/ a basically stock 07 Coupe and 06 Z06 ran even hotter than I did. Was I babying the car?

Here are some solutions to keeping the car cooler when at the track (unfortunatly, I cant afford all of them at once but tell me what you think is the best bang for the buck).

1) Heat Extractor Hood
2) Oil Cooler
3) Kit from A&A to put the radiator back to its stock upright position
4) Meth Injection
5) Shoot the car with my .45

Sorry for the novel! I’d appreciate any thoughts you guys have!!

Steve

 

Oil Cooler and meth for sure if your going to road race. Also make sure your AC condensor is very clean and the foam seal between it and the radiator is still there. You didn't say if you were running a 160* thermostat, run one..Also program the fans to come on high instead of the 2 different speeds that are set in the computer..Other than that you could try to switch back to the stock fans to make sure its not the spial fans causing problems...Good luck

 

Thanks, I will check out the AC Condensor. I have no foam seal at all between the radiator and AC... the AC just hooks directly to the front of the radiator. Whats the purpose of the foam? I do have a 160 thermostat, but I think that just delays the enivitable... I need a way to control high end temps, not when the thermostat opens... does that make sence? I need to check what settings my fans are set on... I appreciate the advice!

 

the foam seal on the sides of the AC cond. keeps air from leaking between the rad. and AC cond. It just makes sure all the air is going through the radiator and not leaking around it....

 

It seems...odd...that changing to a larger radiator and keeping all the stock ductwork made highway temps go up. Don't take this the wrong way, but are you sure that all the air is out of the system?

If it were me I wouldn't go for more mods yet. I'd try and figure out what's going on with what you have.

 

The Dewitts is so thick that A/C condensor coil sits very close IMHO. I spaced mine 1/4" further away to create "air gap" by installing 1/4" thick piece of aluminum behind the coil hangers. In addition I also have Andy's upgrade to position the radiator in a more upright position. That along with some other tweaks make me cool on the streets, but have never tested it on a road course. Good Luck with Your Car

 

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No, having air in the system is a very legitamate question... I followed what the dealer service manual said about refilling and running through new coolant... I did what it said and then once more for good measure. Once the thermostat opened I squeezed the length of the entire upper radiator hose to ensure I'd forced out any air. Theres something odd about admitting you squeezed a hose... sorry I couldnt phrase that better. -Steve

 

Your oil temps are great for not having an oil cooler.. just need to get the coolant temps down a bit. The addition of one will lower coolant temps a tad but if your like me the goal is to run 100% all day long. What that will take, I've yet to see personally.

I'm hoping jbsblownc5 will chime in and give us his secrets..


Arnel

 

I think the oil temps are okay... but like you said, running 100% all day with an FI engine is elusive. If I remember right, in a 20 min session I'd get in 8 lap... on my last session I ran the first 3 hard, then took the remainder easy... 103 degree heat is hard to defeat... I appreciate your input though!

 

Just want to add one thing to the thermostat bit... with a 160, there is no way for any type of fan system to cool it down enough on a hot day, therefore it will always stay open, which will keep the coolant constantly circulating....

Maybe a 180, were there is a possiblity of it cooling off enough to make the thermostat close, which would give the radiator time to cool the coolant in itself before it starts to send it back thru the motor ?

I say the above, because I ordered a 180, and got a 160, didnt pay attention to the packaging and put it in..

Just my 2c.

Nick

 

If you go with making the radiator more upright definitely let us know how that improved things Definitely what I would do next if I were you. The extractor hood helps period.. just costlier up front.

One thing you don't list which is what I'll be going with next is a bigger (1gallon) coolant expansion tank.

Arnel

 

Running a FI vette on a roadcourse at 80% or better in hot temps, will help you find the weak link in your system REAL quick!

I run a BECOOL Rad, that is a bit lower now, since I switched to the ECS bracket and Novi 2K. I run 75% distilled water, and 25% coolant. I mix in a can of 40 below. I run sepperate oil/tranny/diff/ and power steering coolers. I run an Air to water aftercooler, that has 2 heat exchangers. One sits in the air dam, while the other is behind the haltech lisence plate screen. I don't have any cooler up against the radiator. Since I've got an 08 on order, I don't feel as bad having recently taken my condensor out...

My fans come on early, and high speed!!

I good PCV system/catch can is a must on the on the track with FI...


JB

 

Aint that the truth!


Nice... Any change or mod in particular that made a significant cooling difference?

 

Thanks for the advice... it does seem intuitive that a radiator thats layed down could be a large source of cooling issues. Regarding the expansion tank, how much larger is 1 gallion than the stock tank? Where do you put the larger one? Does it cram into the same place? Can you recommend a manufacturer?

Interesting... what temp did you set your fans to turn on? I do have a good PCV system and catch can, but it appears to catch nothing... is oil supposed to accumulate in the catch can? Theres rarely anthing in mine... I question whether it works...

You all rock... thanks for giving me food for thought!

 

i agree making the radiator more up right will help out the most and putting in a 180 thermostat. what do you have your fans set at?

 

You have to get the intercooler away from the radiator cavity to get proper cooling. With the A&A system, on hot days the intercooler pumps very hot air directly into the radiator and causes the overheating problems you have. I had that system....it overheated, detonated and blew up my motor. I redesigned it from the ground up....placed the intercooler in a Tiger Shark nose....put a shroud between the bottom of the intercooler and the top of the radiator. I have an extrernal oil cooler in the front of the drivers side wheel well. These changes dropped temps from 230-235 to 185....even on hot days .

If you do alot of road racing...get the intercooler away from the radiator and into a direct, perpendicular outside air stream.

 

I called my tuner yesterday, MC Racing in the KC MO area, and the fans are set at 180 & 200... they mentioned that by using a certain type of relay, I could get both fans to turn on at the same time and at full strength... can you guys validate this or give any how to details?

Truly an interesting and original idea that I'd never considered... I'll definetely check if I have the clearence to move my intercooler as you did. Let me ask you this... what about the fact that the upper part of your intercooler is blocked by the front part of the cars frame... does that restrict air flow through it? Is this an issue? -Steve

 

Never heard of needing to add a relay. The fans are computer controlled. The both to turn on at the same time as it is. Either on low speed at the 180 or high speed at 200. All they need to do is change the high speed to 180 as well in the computer...No relay needed...

 

The front crossmember is notched to clear 100% of the intercooler....I added a plate at the top of the crossmember notch (angled down about 30 degrees) to deflect intercooler exit air down to the shroud and give a box structure to the front member. If you have any questions on this design...send me a PM and I'll give you my phone number.

This system works so much better than the intercooler on the radiator systems...... its well worth the time and $$$ to convert.

 

I like the way that looks... It appears to channel the air straight to the radiator and condensor.