Normal operating temp?
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Melting Slicks
Joined: Dec 2006
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From: Orange County California
Normal operating temp?
Aside from putting a 163 degree thermo, what is the normal operating temp of a C7 (GS, but I don't think it would make a difference). I think I read that our thermostats close at 190? and of course much above 220 and you're asking for trouble. But is there a spec on where it should be normally operating?
Melting Slicks
Joined: Nov 2012
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From: SUFFIELD CONNECTICUT
Aside from putting a 163 degree thermo, what is the normal operating temp of a C7 (GS, but I don't think it would make a difference). I think I read that our thermostats close at 190? and of course much above 220 and you're asking for trouble. But is there a spec on where it should be normally operating?
Melting Slicks
Joined: Nov 2012
Posts: 3,163
Likes: 686
From: SUFFIELD CONNECTICUT
Aside from putting a 163 degree thermo, what is the normal operating temp of a C7 (GS, but I don't think it would make a difference). I think I read that our thermostats close at 190? and of course much above 220 and you're asking for trouble. But is there a spec on where it should be normally operating?
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Otherwise you'd see temperatures well below 194 in the winter.
My 2015 z51 ran at 194 all year long in Texas in highway cruising.
Last edited by BrunoTheMellow; Dec 28, 2019 at 09:16 PM.
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On a 3 hour highway trip on a 70 degree day my Z06 temps stabilized at 190 coolant and 190 oil. On track at wide open throttle the coolant temps stabilize in the mid 220s and oil stabilizes in the mid 270s within a lap and pretty much stay that way for a 20 minute session. As you can see dropping to a lower thermostat does nothing to keep temps down since at 225 degree coolant temp the stock thermostat opened a long time ago. Some people claim having the lower thermostat slows the rate at which the coolant heats up but that is a false hope. When I head out on track not only is the coolant not up to temp but the rest of the car and the drivers are't either. It takes that lap to get everything up to temp and ready to run hard. Installing a lower temp thermostat in your car even though you are in sunny, hot California will only lower idle temps which really doesn't mean much.
Bill
Bill
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Melting Slicks
Joined: Nov 2012
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From: SUFFIELD CONNECTICUT
I don't think that's correct. 194 is the cracking temperature, or opening temperature. That's why a Z06 runs at 205-210 ish. Not 194 on the dot.
Otherwise you'd see temperatures well below 194 in the winter.
My 2015 z51 ran at 194 all year long in Texas in highway cruising.
Otherwise you'd see temperatures well below 194 in the winter.
My 2015 z51 ran at 194 all year long in Texas in highway cruising.
Tech Contributor
Joined: Jan 2015
Posts: 5,690
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On a 3 hour highway trip on a 70 degree day my Z06 temps stabilized at 190 coolant and 190 oil. On track at wide open throttle the coolant temps stabilize in the mid 220s and oil stabilizes in the mid 270s within a lap and pretty much stay that way for a 20 minute session. As you can see dropping to a lower thermostat does nothing to keep temps down since at 225 degree coolant temp the stock thermostat opened a long time ago. Some people claim having the lower thermostat slows the rate at which the coolant heats up but that is a false hope. When I head out on track not only is the coolant not up to temp but the rest of the car and the drivers are't either. It takes that lap to get everything up to temp and ready to run hard. Installing a lower temp thermostat in your car even though you are in sunny, hot California will only lower idle temps which really doesn't mean much.
Bill
Bill
Same starting speed, my friend at 213 coolant hit 155 max, and at 246 coolant, he hit 148 max at the same point on the straight. That's about 1 mph loss per 5°F coolant temp.
With that being said, if the car has enough cooling capacity, it will be faster with temps settling at say, 200° vs 220°. Our thermostats are rated at opening temp. The stock tstat is fully open at about 215°F.
I run a "170" tstat but it's really 175ish as it rarely gets below 176 in winter cruising and 180 in summer. Adding about 20° for the tsat to get to full open temp, gets you 195-200 degrees. With that said, my oil cooling system is standalone so it runs 250-265 on track, 190-200 on street. Tstat for that is 200 but there's bleed-by to keep cooler oil moving.
Now to comment on track driving:
1) running stock tune means the fan doesn't come on until 194°. Idling at grid will get you to "proper" temps even if your tsat is lower.
2) you have tires to warm up, by the time your Out lap is over and you are about to start running at WOT, your coolant and oil will be up to proper operating temperatures.
With that being said. I do not think running the commonly used 160°F thermostat is a good idea on any car especially not a car with the stock oil cooler. My tstat is the lowest I'd go.
Last edited by BrunoTheMellow; Dec 28, 2019 at 09:43 PM.
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Bill, I agree and disagree to some points. The z06 is known to make more power with lower coolant temperatures. Example:
Same starting speed, my friend at 213 coolant hit 155 max, and at 246 coolant, he hit 148 max at the same point on the straight. That's about 1 mph loss per 5°F coolant temp.
With that being said, if the car has enough cooling capacity, it will be faster with temps settling at say, 200° vs 220°. Our thermostats are rated at opening temp. The stock tstat is fully open at about 215°F.
I run a "170" tstat but it's really 175ish as it rarely gets below 176 in winter cruising and 180 in summer. Adding about 20° for the tsat to get to full open temp, gets you 195-200 degrees. With that said, my oil cooling system is standalone so it runs 250-265 on track, 190-200 on street. Tstat for that is 200 but there's bleed-by to keep cooler oil moving.
Now to comment on track driving:
1) running stock tune means the fan doesn't come on until 194°. Idling at grid will get you to "proper" temps even if your tsat is lower.
2) you have tires to warm up, by the time your Out lap is over and you are about to start running at WOT, your coolant and oil will be up to proper operating temperatures.
With that being said. I do not think running the commonly used 160°F thermostat is a good idea on any car especially not a car with the stock oil cooler. My tstat is the lowest I'd go.
Same starting speed, my friend at 213 coolant hit 155 max, and at 246 coolant, he hit 148 max at the same point on the straight. That's about 1 mph loss per 5°F coolant temp.
With that being said, if the car has enough cooling capacity, it will be faster with temps settling at say, 200° vs 220°. Our thermostats are rated at opening temp. The stock tstat is fully open at about 215°F.
I run a "170" tstat but it's really 175ish as it rarely gets below 176 in winter cruising and 180 in summer. Adding about 20° for the tsat to get to full open temp, gets you 195-200 degrees. With that said, my oil cooling system is standalone so it runs 250-265 on track, 190-200 on street. Tstat for that is 200 but there's bleed-by to keep cooler oil moving.
Now to comment on track driving:
1) running stock tune means the fan doesn't come on until 194°. Idling at grid will get you to "proper" temps even if your tsat is lower.
2) you have tires to warm up, by the time your Out lap is over and you are about to start running at WOT, your coolant and oil will be up to proper operating temperatures.
With that being said. I do not think running the commonly used 160°F thermostat is a good idea on any car especially not a car with the stock oil cooler. My tstat is the lowest I'd go.
Last edited by rrsperry; Dec 29, 2019 at 09:21 AM.
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Not trying to start anything here, but, Just because your friend ran 7 mph slower doesn't mean it was because of coolant temp. Perhaps he's not a good driver, (or he IS a good driver) and still overused his tires and had a slower exit from the corner? Unless you have data logs showing that the ECU was pulling timing and reducing power because of excessive coolant temps, all you really have is conjecture.
I picked laps A and B with the exact same corner exit speed and WOT the entire time. 7 mph isn't just a fluke. That's a huge difference in a straight.
Actually I just looked back at my notes:
A third lap, call it Lap C) 233°F coolant temp, coming out of the corner 3 mph faster than lap A) 213°F coolant lap. Lap C still ended at 1 mph higher at top speed (before braking on either lap). That means that from 213 coolant to 233 coolant, he lost 4 mph.
Also we have tables that show timing pull due to engine coolant temps.
Last edited by BrunoTheMellow; Dec 29, 2019 at 12:32 PM.
Thread Starter
Melting Slicks
Joined: Dec 2006
Posts: 2,308
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From: Orange County California