Ok, so it is the dog days of summer and I want to go to the track. Last time I did that the car went into an over temp situation and I shut it down when the coolant temp hit 245. I have an STS twin turbo setup with a large Dewitt radiator. I've been looking at several options.

1. Add a Methanol injection system with manual control.

2. replace the existing fans with a larger set. This will supposedly increase air volumn 100% (I also run a V3R from SacCity Corvette that lets me turn the fan on manually.)

3. It has also been suggested I upgrade the water pump to a high flow pump to get more coolant running through the engin and radiator.

4. Change the Tstat to a lower temperature.

Clarification when I say track I'm talking about a 2.5 mile road course where I'm running high RPM's in 3rd gear. It has also been suggested that I short shift to 4th to lower the RPM's

I'd like to do more road courses but want to figure out this overheating issue. If you run meth, what temps do you see for coolant? assuming an 80 to 95 degree ambient temp day? What other mods have you done or tired (not including cutting holes in the hood)?

Also it should be noted that this is a track issue as a daily driver in hot weather with A/C on the car runs in the 200 to 215 range depending if I'm on the street on freeway.

Thanks for the thoughts

 

program your fans to turn on sooner and run longer

 

George, are you running a engine oil cooler? Bet that oil gets really hot from the turbos and generates a lot of heat to the engine.

 

Oil cooler is integrated with the radiator I'm not running a seperate one. Remember since the Trubos are all the way in the back the oil is getting cooled as it is circulated from front to back. Also no turbo heat in the engine bay.

I have watched my oil temp and it only runs about 10 degrees warmer than the coolant. This would indicate that every thing for the oil seems to be ok as I believe the target is 20 degrees or less than the coolant.

 

run a oil cooler it will help. your coolant is absorbing a ton of oil heat eliminate that and and it will be that much easier on your coolant.

 

So now that I've read the threads on oil coolers what would be best to add a standalone oil cooler or upgrade the fans. It is clearly an air flow issue I am having based on the temp profiles I'm seeing as I'm driving around this summer.

 

Larger fans might help.

Higher flow water pump may or may not help. If the problem isn't water flow, then moving the water faster through the radiator will not help.

Lower t-stat most likely will NOT help, but can't hurt.

Bottom line is I would try the fans first, the water pump second. The t-stat is cheap so you might as well do it. By 245 the t-stat should be wide open anyway.

The oil cooler should help as well. It might be a case of any one thing not doing it, but a combo of things SHOULD get it.

 

DeWitts has a drop-in fan module that moves considerably more air. Check'em out. Also might think about having the fan turn on/turn off temps re-programmed in the pcm too.

 

That certainly won't hurt, but at best it will delay overheating, it won't prevent it.

Edit: the same is true for the lower t-stat temp. It will delay the overheating a bit, but won't prevent it - unless your current t-stat is defective and doesn't fully open.

 

I'm thinking about both but want to know which does the best job. Fans or oil cooler?

 

The oil cooler will be the cheapest. The fans may help the most, but the variable that I don't know is how much more air will the fans really provide? I mean if your already moving at high speeds that alone will move a lot of air.

I'm thinking your question may be best asked to STS or any of the supercharger manufacturers. I understand it's a pretty common problem with autocrossed FI cars. So rather than educated guesses I'd go to those with the experience. Did you ask this in the forced induction section?

 

My earlier post was a bit confusing. Personally, I think oil cooler, then fans with the larger pump last.

But again, there are probably hundreds out there that have already solved this. Ask them and don't reinvent the wheel here

See what STS has to say and please let us know what they say and how it works out

 

Never said or implied it would. Notice the word "too".

 

substained high revs + twin turbo on a road course just sounds like trouble... even i short shift sometimes on the road course just to keep things cool and im a N/A cam only c5Z. with all the added power from twins, i cant see the need to rev the crap out of it. thing must make killer power. how ur brakes hold up?? how high do ur oil temps get?

 

I never said or implied that you said or implied that

 

The ZR1 can overheat! That's FI on pump gas! How about some 100 octane as being the easiest?

 

I run a SC in FL. and my temp with the AC on is 178 degrees.
You should consider several ways of keeping your temp's in
check.
1. 160 degree thermostat
2. oil cooler
3. I have a vented hood
4. I have programmed my fans to come on earlier
5. I run alky injection
6.I have a vent on the front of the car
This was how I mastered the heat problem. You will need to find
the combinations of mod's that will control heat. Good luck.

 

While I agree you need to optimize your airflow, I don't think that's the clear issue. More I think you're seeing the result of high power operation for an extended period of time (compared to a 1/4 run) vs. loafing on the street.

Note that having the fans run continuously while at speed can actually hinder air flow. Several folks that have been tracking for years recommend cutting some relief holes in the fan shroud, and cover them with a flap of neoprene rubber (like out of a tire tube). This will allow more airflow when/if pressure builds up between the radiator and the shroud.

Another thing you could look at (not cheap) is a heat extractor hood.

Not knowing about FI setups, is the methanol suggestion just to cool the inlet air, or actually spraying the radiator?

HTH, and have a good one,
Mike

 

I would do the things 1st that are the cheapest and easiest
1. Absolutely go to a 160* thermo
2. Adjust BOTH fans to come ON earlier
3. The stock tune has the #1 fan turn OFF at 35 MPH !! and
the #2 fan OFF at 90 MPH--Deffanitely would adjudt these fan off MPH's
4. The min "run time of the #1 fan is 50 seconds---and #2 min run time is only 26 seconds !! again reprogram these to NOT turn OFF
It's been my experience once you get these cars HOT--they stay HOT so the key for me has always been to prevent them from getting there

 

No, it cools the inlet air and raises octane. Spraying it on the radiator would be almost like spraying gasoline on the radiator.

Good thoughts in the above post, but I still say a call to STS is worthwhile.

Remember that supercharged cars have the same issue, so talk to some of them as well.