Redline Water wetter, Amsoil dominator coolant boost, Motul mocool
 

Which one has less issues when mixed with our factory filled antifreeze and really lowers engine coolant temperatures?
From personal experience in my previous car Water wetter is causing buildup of sludge in the cooling system if not changed frequently, about Amsoil Dominator I have read that has a tendency to cause rust to water cooler but what about Motul mocool?
The reason I ask is that knock is directly affected by coolant temperatures and even 5 Celcius degrees have impact in total advance timing!

Why not just tune the car's fans to turn on at a lower temperature? Seems like a better solution to your concerns.

Even IF you added something to your coolant, when your coolant does warm up to 180? 190? or whatever it was, only then will your fans turn on.

Meaning, all you've done is Delay your concerns of "overheating".

Why are you trying to lower coolant temperature? The factory radiator is honestly overkill for how this car is setup and the factory fill coolant works perfectly fine. The only thing this needs additional cooling for is the engine oil, which is a separate loop anyway, typically.


If you're seeing knock on your data logger, you should be looking at fuel quality, not at coolant temps unless you've got data showing your coolant temps are at an improper level.

Agree with others that coolant temps are not an issue. I datalog at the track, and the highest peak coolant temperature I've seen is ~208 F. In daily driving, temps stay between 195-203 F... meaning that even if you're constantly redlining the engine, coolant temps aren't affected that much over nominal.

IAT's seem to have a much bigger effect from what I've seen.

Lastly my friend had an overheating issue at the track with his supercharged E46 M3 and tried water wetter. It barely made a difference. Basically delayed the overheating by a few minutes. His coolant temps hit 240+ F either way.

I agree coolant temps isn't an issue and already set lower the point where the fans turn on, but lower coolant temps help keep flkc low at high speeds/gears so there is benefit from keep them around 90-93C (195-200F) no matter the fuel quality that isn't the best localy!

change termostatic valve to a lower one, like cosworth (76C) or the other ones at like 82C
but i dont understand how you have climbing coolant temps , i never passed 90/91C even tracking in small circuits
maybe what you want is an oil cooler. Or ecutek so you can adjust timing VS oil temperature

I'm not sure I understand. If you're having temperature problems at high RPM, your issue is very strongly going to be engine oil temps, not coolant temp. Doing improvements to your radiator cooling is not going to help here at all. You probably need to get an aftermarket engine oil cooler.


Are you seeing knock in your data logger? If you're seeing knock, it could be caused due to damage that's already happened due to drop in oil pressure due to high oil temperatures. It could also be from poor quality fuel. If you can't access high quality fuel, I'm not sure what to suggest as this car requires high quality fuel due to the high compression engine design.

I haven't seen high coolant temperatures just want to keep them at lower possible area as they favor advance timing.
Plus I don't trust aftermarket lower temp thermostats even from Cosworth, sorry, this is from personal experience as I was Prodrive and Rogerclark Motorsport dealer in the past and have seen plenty of them having problems stuck open or closed.
A lower thermostat does nothing when you press hard the car above a level just give you some more time until you reach same coolant temperatures and it probably increases long term engine wear.

If I go the Ecutek route there are plenty of benefits in Racerom Tom as you know, say per gear timing etc but I already am out of my plans, my aim was to flaten the torque deep and have some more midrange torque and found myself searching for more power.
It's better to give my money for brakes and suspension rather for the last ponnies that can't be easily extracted!

How high of a coolant temp is too high for this platform?

I've definitely seen over 215F in my car during spirited driving. Not sure if that's attributed to my intercooler heat soaking my radiator.

I never trusted this kind of additives. I am using JUST the factory approved engine coolant. About the engine thermostats, the OEM one is a good compromise between performance and emission restrictions. It is true that some aftermaket thermostats had issues (e.g. a few from Mishimoto). The one from Cosworth is different and seemed to me of same or even of higher quality comparing to the OEM. A good idea before the installation is to test it with hot water just to exclude that you don't have a defective part. About its effect in real world, I did once a logging on the autobahn and the temperature did not increase at all. The test was quite lengthy and while the coolant temperature stayed same, the oil temperature rised quite high (no oil cooler). In general, a lower thermostat works in these cars because of the NA engine nature and the oversized factory radiator. A long term increase in engine wear might exist, but this could be said more or less for any changed OEM part with a tuning part. Value for money is not the best option with not massive gains, but if you change the exhaust manifold you can work in same area and do the installation with small effort. Then it is a matter of tuning to extract the extra power ...

I thought the radiator of thsese cars are garbage, thin and plastic

I'm not sure where you heard that, but there is lots of information on this very forum that the stock radiator is good enough for hard tracking by even the best drivers. I believe CSG Mike is still using the stock radiator as well, although with other supporting mods such as a vented hood and replacement shroud/fans.

But a lower thermostat only extends the time the car needs to achieve the same (high or not depending of cooling capacity of factory system) coolant temperature of a car, it doesn't lower max temperatures at all, helps for some spirited driving but not for prolonged hard use.
On the other hand rarely a medium quality part is defective from the factory, after many kms you'll see the difference between a quality one and a Chinese imitation so no need to test if it opens or not first, I have seen aftermarket lower thermostat from the same factory as OEM to fail!
I am with you regarding oil/coolant additives, the only one time I used water wetter I've had bad experience that's why I ask.

I am aware that Cosworth is using a thermostat supplied by NIPPON. They had a supply issue in the past and for some time they were using a thermostat from Mishimoto, but they changed afterwards the supplier. At least mine isn't a Mishimoto. You could see it in the stamp on the thermostat. About temperatures the max. I've seen is 83C and oil temps in the range of 115-120C. Of course, the air temperatures here are not very high and I don't have an A/C radiator meaning a better airflow to the coolant radiator. What Cosworth reckons is that you get 2-3 additional hp with the better advance. So as I said not a must change, but nice to have.