I run events in SoCal (SOLO, CS) and have been running pretty high coolant temperatures - close to 230F(110C). Practise days are especially brutal - and I try to keep the engine running in-between runs (with the AC ON to force the fans to come on) and popping the hood - doesn't help much. Had a few questions - would love to hear what everybody thinks:

*Does running at 230F have an impact on engine reliability - is there any power reduction?

* Will using a lower temperature thermostat help? I know it will not help with sustained high power operation, because it will be limited by the dissipation capabilities of the cooling system - but could it help for the short duration high power operation in AutoX?

* Does the Koyo radiator have better dissipation compared to the stock radiator? Would it be legal in Street Class?

* Is there a way to recondition oil coolers with bent fins - will this help?

Any thoughts will be greatly appreciated.

 

*IIRC, 240 F. is about where OEM coolant seals begin to degrade. While you may not have done any damage, I would not want to continue flirting in that territory.
*In my experience, a lower t-stat threshold mostly just slows the rate of warm-up on a cool day. Otherwise, it didn't do much.
*IIRC, an aftermarket radiator is NOT allowed in Street. I don't THINK you can make radiator changes until Street Prepared Class.
*Not sophisticated and it's pretty tedious, but I use an old mini-file that's dimensionally close to the folds of my oil coolers, and an old pick. I open a completely closed/bent fin with the pick and shape it with the old mini-file. I think they make a "comb" of some sort for doing the same thing, but this has worked for me...and I only do it once a year or so.

Some other things to try if you haven't already:
*As much distilled water up to about 80%. Personally I keep ~ 20% coolant for lubrication and to prevent corrosion. You can try one of the 'water-wetter' products but personally I didn't see much if any improvement on my temps with them.
*Get some upholstery foam and plug up any gaps around the radiator.
*I ran a thermoswitch that activated fans earlier.
*Seems obvious but I've seen some radiators that are pretty packed with crap between the A/C condenser and face of the radiator.
*Quality synthetic oil.
*I had an old-fashioned 4 gal water fire extinguisher that I took on REALLY hot days and charge it with the little air compressor I used for tires. Right after a run I'd idle back to the paddock area, park and open the hood. I'd let the turbo timer keep the car idling a minute or two while I squirted a little water on the radiator and oil coolers faces.

 

While running the AC does turn the fan on, it also puts additional load on the engine by bumping the idle and turning the AC compressor. Instead try turning the heat on high. We also used a water sprayer to soak the oil coolers.

You can only use an OE style replacement radiator in street (stock) class. One that would actually perform better, like the aluminum competition type, would not be legal.

 

I would suggest the Re-Medy water pump and thermostat. I used to see 220+ at the track, barely get to 210 now.

You don't want to spend too much time over 220...

For the oil coolers, you can gently straighten them out with a toothpick, and you can open up the openings in the wheel liner behind them to promote better flow. You can even put fans behind them, but not sure how much change you'll really see.

 

Don't run the AC while idling and that will solve your problem... all that is doing is feeding hot air from the condenser straight into the radiator...

And shut the car off after like a minute of sitting after the run, instead of sitting there idling all the time. You can also turn on the heater to help cool it down faster.

You are doing it to yourself. Keeping temps in check for little one minute blasts isn't too hard.

 

Check out the Congrats thread below. It has some cooling tips as a collection of DIYs. The Foam on is a big one, fans on low is good too. I agree with not turning the AC on, it dumps a lot of heat into the stream. It is a good idea to get the fans on, but there is an easier way. You can also set the fans up to be on high, but at idle, low should be fine.

 

Thanks for all the suggestions. Sounds like I should be able to manage the temperatures a bit better - and I will also look into the modifications.

I have been running the FL-22 coolant - is there some potential benefit in moving to one of those fancy coolant mixes with a higher percentage of water?

 

The more water the coolant contains, the more heat it can carry (specific heat capacity of water is 4.179 J/gram*C, almost 2-fold higher than ethylene glycol at 2.2 J/gram*C). Just ensure that the coolant mixture you go with is sufficient for the coldest ambient temperatures you anticipate the car to operate under.


I run the heater at full throttle to expedite temperature reductions. On particularly hot days (>95 F) coasting up and down the paddocks before returning to grid has also proven to be beneficial, as has spraying the oil coolers/radiator with water.

 

Thanks to all the comments on this thread - I've been able to manage temperatures much better now. I do the following:
* Did not run AC - like it was pointed out - it doesn't help much and leads to higher temperatures after a while.
* Immediately after the run - (liberally) spray the oil coolers and spray into the front radiator opening - this brings down coolant temperature by about 5-10F
* Stop the engine after about 1-2 minutes.

This pretty much helped keep temperatures in check even during a long practise run.

 

Add the fans on cool mod and you should be good to go.

Glad things are better.