froggy47

2004 z06

This is on the Roval if you are familiar with it session 3 (about 2:30) after about four laps I got high coolant temp warning 254 deg F and backed off 2 laps dropped to 240 deg F.

Got back into it, passing etc., back up to low 250's, backed off goes down etc.

Car pulling like a train, great power.

44k miles stock setup, the air dam is good, the fins are clean, running 25% water with wetter, 160 stat, all that stuff, fans run fine.

Oil about 20 degrees higher & good pressure at all times

Is it fair to simply conclude the cooling system, as built, is simply inadequate for most hot summer track days?

So if you enjoy summer track days, just suck it up & install a better radiator?

Thanks guys.

froggy47

redtopz

I think a new larger radiator will definitely help if you still have the stock one. My water temps were getting up to about 238 in my nasa race there a few weeks ago during a 30 minute race and I thought that was too hot, but apparently it's pretty normal. It was a very hot and humid weekend and that track keeps the engine at full throttle most of the time. Part of my problem is I've never really paid close attention to water temps before so I didn't have any benchmarks for comparison. But since I had just pulled my heads and done some top end work before the race I was keeping an eye on water temps and they seemed high to me.

froggy47

Thanks,

Other track days I have run (not that many) were in the fall/winter & I never paid any attention to coolant temps except to see they were 220-235 ish.

There is a lot of high rpm shifting 2/3/4/5 at Fontana so I was definately up there in the rpm's most of the time. Hit RL a couple times for a pass.
I think your 238 at this time of year means you are just fine.

Anyone know if c6z is also borderline on HOT days?

sothpaw2

Yeah I think summer days don't mix w/the stock system once you start driving the car competently in intermediate group. My mechanic suggested a Dewitts rad and that his other customers that do this have them already.

froggy47

fatbillybob

I'm a T1 racer and I never look at water temps period. I just watch oil temps. My only comment about water temps is that you should know the pressure of your system listed on your cap. My 04 C5Z06 came stock with a 15psi cap which recently failed in old age and the oem replacement cap is an 18psi cap. That will raise the boiling temp of the coolant relative to the antifreeze mixture or lack thereof. So as long as you always under the coolant boiling point you have functional coolant and the oil temps are the ones to watch. With 15psi cap water boils at about 250F and with 18psi about 260F. You get about another 10F with 50/50 antifreeze and water but really you should not run antifreeze when on track because it is like oil if it leaks on track. Use water and water wetter. I do run fontucky and don't seem to have any issues with a stock radiator and a giant oil cooler. Many like the ron davis radiator and you can't go wrong with that but you will still need to cool the oil. Perhaps cooling my oil is why I can run the stock radiator.

nhpln

I was also there on Saturday for the Corvette Challenge. My max coolant temp (stock C6Z06) was 235. This was consistent with another stock C6Z06, however there was someone that had overheating issues.

http://forums.corvetteforum.com/c6-z...the-track.html

froggy47

I read that other thread & so far as I can figure it may be my radiator needs MORE cleaning & check that all the plastic that directs air flow is good.

I keep it clean every event & blow it out about once a year but haven't blown it out in about 18 months.

Thanks all.

Owner's manual should advise add qt of oil AND blow out radiator when tracking.