Walt Kowalski

Curious to know what coolant temps people regularly see in endurance race conditions - say three hour races?

What is normal for an LS? Some say 110 is normal. Seems very hot to me.

I'm seeing 115 regularly and my engine builder/tuner says that's no problem as he has tuned for those temps and with quality oil and "Liquid Intelligence" as coolant there is no coolant loss even at much hotter than 125 degrees.

I have the yellow warning light set at 115 and the red at 125 degrees because I'm wary of this issue.

Thanks for any tech info.

3.8redbird

iTrader: (3)

Celsius correct?

Walt Kowalski

Sorry. Celsius.

240F yellow warning
260F RED light

3.8redbird

iTrader: (3)

Seems pretty high but I have never done longer than 20 min stents.

LLLosingit

iTrader: (4)

I wouldn't think you would want to stay above 100 for long.
It doesn't matter if you race for 20 minutes or 20 hours, After a few minutes of racing you should already be at or near max normal operating temperature and it should stabilize.

3.8redbird

iTrader: (3)

Well after a 20 min session I am between 210-220 but I have a few cooling mods. Back down to 200 in 2-3 min cool down.
Hoping to keep it below 210 with a lil water wetter and cleaning up passages.

1981TA

iTrader: (7)

On the track, mine rarely sees 200 F / 94 C. My fan is set to kick on at 180 F / 82 C - temp measured at the outlet of the water pump. If all is going well, it pretty much stays at 82C, with a slow rise to 190F/88C until the fan starts.

That is in a 25 minute session. On the highway, cruising at 80 MPH (@130KPH) it rarely goes above 160. The worse is city driving, stuck in traffic with no air blowing through the radiator. Last year, I had a bad fan relay, and the car saw a couple peaks over the boiling point then.

athornt2

iTrader: (18)

My water temp will be anywhere from 180-220f/82-104C depending on the time of year. Our races are 30-45 minutes long. Oil temps will be anywhere from 230-270F/110-132C depending on the time of year.

Midnight02

iTrader: (8)

I typically do not see anything above 200*F on track. 30-minute session at Road Atlanta with temps in the high 90's and still a tick under 200*.

Nothing particularly special about my setup (clean fluids + water wetter).

FNelson

thunder hill 25 minute sessions I see around 210f radiator and 240f oil at end of the session then cool down lap its back to 200f.

gnx7

iTrader: (28)

Hi Walt!

With inadequate cooling on my first conversion and no ducting or hood venting I would see 240* coolant temps in 100*+ hot weather after 20-30mins and stock LS1 water pump. I used a 4000cfm Ford Taurus fan.

2nd conversion has a fully ducted Howe dual pass radiator with distilled water and Redline Water wetter, hood venting, and Ford Taurus fan. I use a coolant vacuum pump that allows another 1 quart or so into the system. It really works and I do burp it and heat cycle it a couple times! My temps have yet to go over 215* in hot weather. 427 LS7 14 quart dry sump oil system on 91 octane pump gas. e85 would likely run a little cooler....

I also run an Evans water pump on the motor which has a better impeller design and I've been told has minimal cavitation above 5,000rpm like a production pump can have.

KiwiKid

Hi Walt,

Been involved in road racing for more than 50 years, raced stock LS7 engines for the last 3 years, and despite what your engine guy is telling you, in my opinion you are running way to hot, maybe not scary hot, depending on your system's water pressure, but way over the most efficient temperature for most engines. As a rule of thumb you should be running around 83ēC for a stock LS7 engine, and pretty much any version of the same.

Interesting that you don't mention the oil temperature, because for sure excess oil temperature will carry the water temp up surprisingly quickly, there is a direct relationship to the two, so if you are up above 125ēC on the oil you have got a potential issue that could cost you dearly.

Are you wet sump'd or dry sump'd?

slowZZZ

Can you elaborate on what you mean by a stock LS7 engine? In the past, my Z06's have had no issues running in the ~230F/~260F range for coolant/oil temp.

79_T/A

iTrader: (1)

Slowz, kiwikid has a thread going in the gen4 internal engine section about using the LS7 in the NZ V8 Supertourers series. New Zealand touring cars similar to the Aussie ones, and he outlined the issues of using the LS7 as a spec motor in that series. Lot of great information there.

slowZZZ

Ah, okay. Completely different content than what I was expecting. I'll check it out. Thanks for the info.