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Hey guys,

Just wanting to know at what coolant temperature did you guys back off at the track and start the cooldown lap ?

I know i should be going off oil temperature but i don't have a gauge for it yet so if anyone knows roughly what the coolant temp is at when the oil is around the 120 degree mark, that will help me heaps till i get the gauge...

Cheers!

It's not really possible to say what the relationship between oil and water temperature will be because it depends on too many factors, such as which thermostat and how well it's working, whether the stock cooler/heater is in place, how big the radiator is, etc etc.

What you can say though is that you really shouldn't be leaning on the engine hard when the coolant is up over 100°C, so you should probably be calling an end to the fun at 105 or so. It's a bit rubbery even there, because it depends on how rich the tune is, what the timing is like, what fuel you're running and so on.

Edited by GTSBoy

I had no issues pushing my coolant and oil to 145 degrees, other than the overflow bottle ended up overflowing. I will be running Evans waterless coolant if I ever take the Stagea to the track again.

Most new cars run 100 degree plus on the road. My thermo fan doesn't even activate till 105.

I usually back off once my water temp hits 120 and/or oil temp hits 140 (which I've never seen)..

I've got alarms for both of the temperature sensors so when it beeps I back off.

I've recently changed my water thermostat to a 67 degree Tridon item, car now runs at around 72~74 - this means I will now have about a 50 degree window before water is getting too hot. In the past I had a R34 thermostat (spares shop gave me the wrong one) car would operate around 90 degrees (which is quite normal for modern cars) however that meant I only had a 30 degree range before things got too hot

Oil wise, I'm running a massive Mocal core and a 80 degree thermostat - highest I've ever seen with the oil is 130.

That's my input (I might be completely wrong too - however car hasn't exploded yet haha)

I find that usually there's a 10~15 degree difference in water temp vs. oil temp when you're going full retard on the track

they're always same same for me, however I still run the factory water/oil heat exchanger which might keep the two very close.

Adding a thermostat that opens earlier shouldn't have any effect on the steady state peak temp the engine gets to. I mean at best it would give you another 20seconds of track time (the time it takes to get from 75 deg to 85deg or whatever).

Only improving flow through the thermostat would. I'd be backing off at 105degrees personally. Depends on coolant as we'll.

Agree that guessing oil temp from water temp is fraught with danger.

Edited by simpletool

Thanks for the replies guys, all really helpful!

Understood - it's a very rough correlation, but just till i get my oil temp gauge, it's better than nothing!

It sounds like i've been playing it quite safe so i might just keep what i'm doing.

Car has a 40mm alloy rad now, standard heat exchangers and standard thermo, running e85 on a track friendly tune via pfc. Coolant temp idle/cruises at around 78-80 and on the track soon as i see the coolant hit 90 i start cooling it down which isn't so much an issue as i get two hard laps at wakefield out of that and i'm only chasing PB's so the cooldown laps allow me to get the tires back to optimum along with all fluids/cooler and intake temp.

My water temp never goes over 100 and my oil temp never goes over 105. I'm running a chinese radiator/standard thermostat and a chinese remote oil cooler. That said I no longer have the restricive air cond condenser blocking the radiator.

Hope that helps

Neil.

I usually back off once my water temp hits 120 and/or oil temp hits 140 )

Im surprised to hear you let it go that high, i was getting maybe 7 laps around mallala before hitting 104 water temp 125 oil temp and cool down then. Std radiator and thermostat, with oil cooler. Maybe i can get more laps in

I worry about how hot some of the material in the head is getting when you let the coolant get that hot. Hot surfaces facing the hot gases are much much hotter than the cold wet side. Heat the cold wet side up 30 degrees above normal, and the hot side will actually end up somewhat more than 30 degrees hotter. This conducts throughout the metal, so even inlet ports and whatnot end up hotter than normal. Just doesn't seem wise to keep leaning on an engine once it gets that hot. Detonation risk increases, thermal expansion increases, softening risk for alloys increases, etc etc. I would either back off at a more sensible temperature or ensure that the cooling systems can cope with the loads required.

Im surprised to hear you let it go that high, i was getting maybe 7 laps around mallala before hitting 104 water temp 125 oil temp and cool down then. Std radiator and thermostat, with oil cooler. Maybe i can get more laps in

Well Nulon says a 50/50 mix of their concentrate brings the boiling point up to 132 degrees.. however I try to keep it below that incase the head lifts or I blow a head gaskets and/or hoses.

However, the extreme heating could have been from a faulty fan clutch, which I have replaced :)

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