Overheating
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Joined: Oct 2005
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From: Durham California
Overheating
I'm overheating the engine water and oil on track days. 250+ water and 300+ oil. I'm going to get a Ron Davis radiator with an integrated oil cooler BUT I've got a NASA track day on Wed. at Thunderhill that I'd like to get through without too much trauma. I'll be driving slower than usual.
What would be the best way to get through the day. I've flushed the dexcool. Would you suggest water only with Water Wetter or water with some antifreeze? Ambient air temps on Wed. will be over 100F. It is supposed to be 110 on Saturday.
What would be the best way to get through the day. I've flushed the dexcool. Would you suggest water only with Water Wetter or water with some antifreeze? Ambient air temps on Wed. will be over 100F. It is supposed to be 110 on Saturday.
Burning Brakes
Joined: Feb 2006
Posts: 1,205
Likes: 5
From: Jupiter FL
I'd go 60/40 water/antifreeze, with a bottle of Water Wetter added. You need the antifreeze to increase the boiling point of the water, and the Water Wetter will help with overall cooling.
Have you checked to make sure that the radiator is not clogged with debris? Consider pulling the shroud from the front of the radiator and checking to be sure it's not plugged up with crap. Blow it clean with compressed air from the back.
Also, change your oil. Fresh oil will help keep the heat down in the engine as well. Consider changing your transmission fluid and differential gear oil also. The smoother the system runs the cooler it will run. Make sure you don't turn the car off immediately after coming off the track. Drive it around a little bit to cool the block, otherwise heat sink will increase internal temps through the roof.
Have you checked to make sure that the radiator is not clogged with debris? Consider pulling the shroud from the front of the radiator and checking to be sure it's not plugged up with crap. Blow it clean with compressed air from the back.
Also, change your oil. Fresh oil will help keep the heat down in the engine as well. Consider changing your transmission fluid and differential gear oil also. The smoother the system runs the cooler it will run. Make sure you don't turn the car off immediately after coming off the track. Drive it around a little bit to cool the block, otherwise heat sink will increase internal temps through the roof.
Melting Slicks
Joined: Jun 2004
Posts: 3,253
Likes: 2
From: Castro Valley CA
The oil temp does not sound that far out of line for the temps were are having now but water temp does sound 20 deg too high. I agree with fasterisbetter, check for debris on the radiator and clean it thouroughly.
Team Owner
Joined: Sep 2003
Posts: 43,084
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From: Raleigh / Rolesville NC
Originally Posted by FasterIsBetter
Have you checked to make sure that the radiator is not clogged with debris? Consider pulling the shroud from the front of the radiator and checking to be sure it's not plugged up with crap. Blow it clean with compressed air from the back.
Also, change your oil. Fresh oil will help keep the heat down in the engine as well. Consider changing your transmission fluid and differential gear oil also. The smoother the system runs the cooler it will run. Make sure you don't turn the car off immediately after coming off the track. Drive it around a little bit to cool the block, otherwise heat sink will increase internal temps through the roof.
Also, change your oil. Fresh oil will help keep the heat down in the engine as well. Consider changing your transmission fluid and differential gear oil also. The smoother the system runs the cooler it will run. Make sure you don't turn the car off immediately after coming off the track. Drive it around a little bit to cool the block, otherwise heat sink will increase internal temps through the roof.
blow out those radiators, may need to flush the radiator too.Change the oil, if you havn't. Two weekends on the track per oil change max. Dont believe the waxers or what it says on the oil bottle of"extended" life. 10-w50, 40w, quaker states 5-w50, in short get away from any 30w oils for track days
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Joined: Oct 2005
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From: Durham California
Thanks for the replies. What is the coolant capasity of engine and radiator, so I can calculate my water/antifreeze ratio? Or do I just dump in a couple of gallons and call it good?
I installed a front splitter that I think may be the cause of the high temps, I've made some modifications to the opening which I hope will lower temps. The front splitter opening was 2 X 25 and now it is 3 3/4 X 25.
I installed a front splitter that I think may be the cause of the high temps, I've made some modifications to the opening which I hope will lower temps. The front splitter opening was 2 X 25 and now it is 3 3/4 X 25.
Drifting
Joined: Jul 2005
Posts: 1,375
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From: Austin Texas
You can also spend less time near the redline. That will reduce your operating temp. Shift a little short. I'd also consider taking a slow lap and pitting early if my oil temps got near 300. Not worth blowing up the car to continue. It's one of the harder things to do when you're having a good time, but pitting early means you get to have them again...
--Yak
--Yak
Team Owner
Joined: Sep 2003
Posts: 43,084
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From: Raleigh / Rolesville NC
Originally Posted by danswofford
e some modifications to the opening which I hope will lower temps. The front splitter opening was 2 X 25 and now it is 3 3/4 X 25.
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From: Durham California
There is a 6-8" gap between the back of the splitter opening and the radiator. It seems that some air could be forced under that car rather than go though the radiator. Seems like the radiator would be a high pressure area and the 4" under the car might me lower.
So I'm thinking about making a fiberglass undertray to close the gap and direct all the air that comes through the splitter opening through the radiator.
Seem like a good idea?
So I'm thinking about making a fiberglass undertray to close the gap and direct all the air that comes through the splitter opening through the radiator.
Seem like a good idea?
Melting Slicks
Joined: Feb 2001
Posts: 2,243
Likes: 1
From: Ooltewah TN
Heinricy said that the testing they did showed the oil temp was OK up to 330, but 340 was an issue.
Water is much better than anti-freeze. I only run about 10-15% antifreeze and the rest is distilled water. The tracks would prefer that you use only water because antifreeze is a bear to clean up - worse than oil.
Other than that, just make sure that the radiator is as clean as possible, that the fans work well, clean oil (50W is not necessary), and if the temps go a little higher than you'd like, short shift a little and maybe run a gear higher than you might think is necessary. You might find that staying in 3d gear thru a corner is just as fast (on the stopwatch) as shifting down to 2d. With that kind of heat, you'll likely get wheelspin and subsequently slip and slide by dropping too low of a gear. Revving the engine higher is not always faster. Use the same philosophy for 3-4 gear too.
Don't forget about yourself - lots of gatorade, H2O, rest, shade, etc. And, I highly recommend looking into a "Cool-Shirt" driver cooling system. Man, they are great!!!!!!!!! That is money well spent!
Water is much better than anti-freeze. I only run about 10-15% antifreeze and the rest is distilled water. The tracks would prefer that you use only water because antifreeze is a bear to clean up - worse than oil.
Other than that, just make sure that the radiator is as clean as possible, that the fans work well, clean oil (50W is not necessary), and if the temps go a little higher than you'd like, short shift a little and maybe run a gear higher than you might think is necessary. You might find that staying in 3d gear thru a corner is just as fast (on the stopwatch) as shifting down to 2d. With that kind of heat, you'll likely get wheelspin and subsequently slip and slide by dropping too low of a gear. Revving the engine higher is not always faster. Use the same philosophy for 3-4 gear too.
Don't forget about yourself - lots of gatorade, H2O, rest, shade, etc. And, I highly recommend looking into a "Cool-Shirt" driver cooling system. Man, they are great!!!!!!!!! That is money well spent!
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From: Durham California
Originally Posted by AU N EGL
There was the problem. Not enough air getting in too cool the radiators. I openned mine up further as well. Now it is 4 x 25. WC cars ~ 5 x 30
Team Owner
Joined: Sep 2003
Posts: 43,084
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From: Raleigh / Rolesville NC
Originally Posted by danswofford
There is a 6-8" gap between the back of the splitter opening and the radiator. It seems that some air could be forced under that car rather than go though the radiator. Seems like the radiator would be a high pressure area and the 4" under the car might me lower.
So I'm thinking about making a fiberglass undertray to close the gap and direct all the air that comes through the splitter opening through the radiator.
Seem like a good idea?
So I'm thinking about making a fiberglass undertray to close the gap and direct all the air that comes through the splitter opening through the radiator.
Seem like a good idea?
I clean the screen before each run.
and as Chris mentioned above about short shifting helps with oil temps more then ppl think. Running too high an rpm causes high heat.
Cool Shirt and drink lots of fluids 
best mod money spent on keeping the body and brain cool. I got a cool shirt and anytime it is above 80* degrees out side I use it.
Le Mans Master
Joined: Sep 1999
Posts: 5,464
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From: Private
It's funny, I have all kinds of sh%t in my car this year (cooler, wilwoods, cam) and I haven't been able to get 30 minutes of track time because my damn car keeps breaking down.
Last 4 years, I had nothing and ran 280F without any problems...this year I run at 215 and everything goes to hell...
Last 4 years, I had nothing and ran 280F without any problems...this year I run at 215 and everything goes to hell...
Thread Starter
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From: Durham California
I drove at Thunderhill yesterday and the engine was cool. Prior to the event I jacked the car up where I could really access the radiator and found huge wads of packed dried grass at the very top of the radiator area. It was about 1/2 cu. ft. or debris packed hard. It could not be seen nor could I get my hand to it without jacking the car up. I took the radiator housings apart to get at it.
The car ran 20 minute sessions at about 240 water and 295 engine oil.
However this leads to my next overheating question. My transmission temp warning is coming on. Some say that overheating transmissions are due to heating my the diff. So which to a add a cooler too, the transmission or the diff?
The car ran 20 minute sessions at about 240 water and 295 engine oil.
However this leads to my next overheating question. My transmission temp warning is coming on. Some say that overheating transmissions are due to heating my the diff. So which to a add a cooler too, the transmission or the diff?
Safety Car
Joined: May 2005
Posts: 3,520
Likes: 3
From: Redwood City CA
FWIW, I was at Thunderhill yesterday with my C6 Z51 ... highest oil temp I saw was 270F. I'm on stock runflats, hitting about 120mph before braking for T1 and T14. We did 6 20 minute sessions.
I was finding I didn't have to shift much... 3rd gear most of the track, into 4th between T15-T1, back to 3rd climbing the Cyclone (braking uphill), up to 4th by the T7 dogleg, back to 3rd at T11, up to 4th just after T13, down to 3rd braking for T14. Occassionally I'd go down to third braking for T2.
I'm a chickensh*t at T8 and brake down to about 70mph for the left; I know I can carry a lot more speed there, though.
Anyway, yeah, 270F was them max I noticed for oil temps but I wasn't religiously checking it... and it'd drop quickly during the cool down lap.
I was finding I didn't have to shift much... 3rd gear most of the track, into 4th between T15-T1, back to 3rd climbing the Cyclone (braking uphill), up to 4th by the T7 dogleg, back to 3rd at T11, up to 4th just after T13, down to 3rd braking for T14. Occassionally I'd go down to third braking for T2.
I'm a chickensh*t at T8 and brake down to about 70mph for the left; I know I can carry a lot more speed there, though.
Anyway, yeah, 270F was them max I noticed for oil temps but I wasn't religiously checking it... and it'd drop quickly during the cool down lap.
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From: Durham California
Originally Posted by gkmccready
FWIW, I was at Thunderhill yesterday with my C6 Z51 ... highest oil temp I saw was 270F. I'm on stock runflats, hitting about 120mph before braking for T1 and T14. We did 6 20 minute sessions.
I was finding I didn't have to shift much... 3rd gear most of the track, into 4th between T15-T1, back to 3rd climbing the Cyclone (braking uphill), up to 4th by the T7 dogleg, back to 3rd at T11, up to 4th just after T13, down to 3rd braking for T14. Occassionally I'd go down to third braking for T2.
I'm a chickensh*t at T8 and brake down to about 70mph for the left; I know I can carry a lot more speed there, though.
Anyway, yeah, 270F was them max I noticed for oil temps but I wasn't religiously checking it... and it'd drop quickly during the cool down lap.
I was finding I didn't have to shift much... 3rd gear most of the track, into 4th between T15-T1, back to 3rd climbing the Cyclone (braking uphill), up to 4th by the T7 dogleg, back to 3rd at T11, up to 4th just after T13, down to 3rd braking for T14. Occassionally I'd go down to third braking for T2.
I'm a chickensh*t at T8 and brake down to about 70mph for the left; I know I can carry a lot more speed there, though.
Anyway, yeah, 270F was them max I noticed for oil temps but I wasn't religiously checking it... and it'd drop quickly during the cool down lap.
I can't drive much faster in that crappy Z06 seat, I got a blister the size of a quarter from jambing my left elbow into the door panel.
Dan
