TKOGTO

What are the generally accepted max temps for oil, coolant and the tranny fluid on track? Obviously temps will vary on a variety of factors (ambient, avg/max speeds, gears used, etc) but I am looking for a ballpark # for each keeping longevity for a dual purpose car in mind.

I have a 2010 GS A6 (LS3) with Kumho Ecsta XS tires.

topmover

If I were you I'd be more concerned about the A6 than the engine oil temp in your set up.

Many more qualified people then me on this site however I think the general rule for oil is below 250 is where you'd like to be. My C6ZR gets much hotter than that however.

topmover

Sorry I missed where you asked for tranny temp/coolant........my point was I'd be concerned in general about the A6. I have a GS A6 and while it is kind of fun at the track I dont think it would live with tires much better than the old style Goodyears that came on the eariler models.

Screamin Z

Id start being concerned if I saw:

Water 240
Motor oil 285
Transmission ?? Probably not as high as motor oil.

Bill Dearborn

Coolant will run somewhere between 200 and 220, oil will run about 260 depending on how hard you push the car. Transmission will be the big issue. Getting those temps down means more cooling system capacity not a lower thermostat. Thermostat sets the minimum temperature once the engine is warm but it doesn't control the max temp. That is controlled by how much heat you make (power) and the size of the radiators/coolers. You can get the coolant a little cooler by reducing the percentage of antifreeze in the coolant since antifreeze doesn't conduct heat as well as water does. Another way to drop coolant temp is to run the heater at full blast. A little uncomfortable in the car but as one of my instructors said a long time ago, "If my engine is happy, I am happy".

I monitor oil temp on the DIC where it is easy to see. I pay more attention to it than coolant temp.

Bill

sothpaw2

Any feel for how many degrees cooler you'd run on water temp if you had the heater on? Never tried it.

travisnd

Racing at Road Atlanta this weekend I saw:

Oil - Max of 269 (Have a DRM cooler with the bigger Setrab 625, stock LS6 turning 6600 rpm)

Trans - High temp warning came on after 18 or 19 laps and got up to 277. Sunday race ended 2 laps after the warning came on. I need a trans cooler.

Coolant - High temp of 225. Running water with water wetter, stock radiator, but no AC condenser in the way and no stock fan shroud to block flow.

I'd start to worry if coolant got much over 235 and oil over 290. That's about where I'd back off.

TKOGTO

FYI:
- my coolant temps max out ~ 210-215, down from 235, thanks to a DeWitts radiator with an EOC and tranny cooler. No antifreeze @ all, just water and water wetter.
- the oil hit ~260 last week with ambient ~ 78, again down large from last yr (296 @ 87 ambient)
- the tranny is another story. Max temps are up this yr ~ 11 degrees vs comparable ambient temps from last yr (252 vs. 241). Larger capacity of DeWitts tranny cooler in the rad vs stock radiator has not helped. Change of the fluid to Amsoil did not help with max temps but temps did seem to cool down more quickly. I am 2+ sec quicker this yr vs last on LRP so that could be the reason. So "if my tranny was happier, I would be happier" too.

blkbrd69

http://forums.corvetteforum.com/auto...-course-t.html

Painrace

Oil temp = short shift at 290 and park it at 300.

Transmission = short shift at 250 and park it at 260. Transmission will start puking fluid out at about 270.

Jim

travisnd

The GM warning comes on at 275. I had mine at 277 for the last two laps of the race on Sunday. Shopping trans coolers now. When the race was over and I got off track it went to 281 due to decreased airflow and heat soak I guess. I use Amsoil Synthetic ATF in my gearbox. Still shifts OK and has 122,xxx miles on it. The last 3k have been all track/race/tt use.

Bill Dearborn

I haven't had to do it in a while but I have seen a 10 or more degree drop in coolant temps. Does get a little hot in the car with the heat turned up to max even with the windows open and triple digit speed air blowing through the car.

Bill

sothpaw2

I take it that running the heater does not rob the car of any power? Simply exposing the passenger compartment to the heat of the engine via the core.

sothpaw2

How do you display the tranny temp? I think these cars need a tranny or diff cooler to run them in hot weather.

C66 Racing

My personal opinion on oil temp is that it varies by grade. Like all fluids, oil loses viscosity as it heats up. A typical 30 grade oil will lose about 70% of its viscosity from 212F to 300F, which will reduce the fluid film strength of the oil. I'd worry about bearings at temps approaching 300F. Many go to a higher grade oil (40 or 50 grade) but I found this to be somewhat self defeating. The higher grades caused increased fluid friction, pumping losses (and less net HP) which resulted in higher oil temps. Over the years I think my stock bearing LS6 runs coolest with a racing 10w30 (that is very close to a low 40 grade).

My personal thumb rules:
- < ~ 260F: 30 Grade
- ~ 260-280F: 40 Grade
- > ~ 280F: 50 Grade

With my DRM racing radiator and an external oil cooler and running AMSOIL Dominator Synthetic 10w30 Racing Motor Oil (Product Code RD30QT) my oil temps are almost always 245F-255F. Two weekends ago at Summit Point WV my oil temp at the end of a 20 lap race in 90F ambient was 248F.

C5 will give a tranny temp warning at about 275F or so (forget the actual number) and at that point temp will show on the DIC - you can't otherwise call it up. I got that warning my first DE day in the C5 Z06 and came in and let it cool. Not too long after I installed a tranny cooler as well.

Now I really have no idea what my tranny and diff temps are, but I don't ever get the high temp warning. Suspect my diff is slightly hotter than the tranny as they are bolted together and the diff has no direct cooling. I change my tranny and diff fluid at about every 8th track day. No concrete data behind that number, though I have never lost a tranny or diff (but have had them rebuilt twice over the years as preventative maintenance).

Early in my racing, I used a stock radiator. Coolant temps were hard to control and upwards of 240F was possible. Now use DRM racing radiator and my coolant is almost always pegged right at 200F no matter track or ambient temp.

JeremyGSU

I ran Sebring the other week in my street/track car. I have a Ron Davis 19R stand alone oil cooler. I run the stock radiator with 70% water/water wetter and 30% coolant.

The highest I saw out of both in 98 degree weather was.

Water - 239
Oil - 271

Water is getting up there IMO. Probably robbing me of power.

I haven't seen my tranny warning come on yet. I don't typically run long enough sessions for it to throw it. You get some serious heat out of the center console though.

blkbrd69

A6 guys