[RESOLVED] Heard it was bad to lower temp.

[1G90AWDTsi]

So I was in a conversation with a buddy of mine, he has a N/A eagle talon with DOHC. He just rebuilt his engine and slapped on the original radiator from his past motor (his past motor didn't blow...it simply had 180k miles).
I asked him why not put on a more cool-efficient radiator like a "B-COOL" and a lower degree temp to allow the motor to run a little cooler than factory for longer engine life. He said the techs that rebuilt his engine said it's not a good idea but didn't explain why...

Does anyone know the answer??

 

[architechnik]

Engines have an ideal operating temperature range that all the components work well with one another. If you go out of this range, things like the oil viscosity will not work properly and will damage the engine.

Now for some other news: the radiator is not what actually controls the lower end range!! Upgrading the radiator will allow the temperature to drop fairly quickly if the operating temperatures start to rise from extreme use. The thermostat is what is controls the lower end, though. If the coolant is not at least the lower range of ideal operating temperatures then the thermostat will remain closed and not circulate to the radiator.

End result: Radiators are good to upgrade as long as you keep the correct thermostat. Extra: If you have a Really good radiator you can go with a specific thermostat that hits a little higher and the radiator will constantly keep it at that operating temperature and make consistent tuning easier.

 

[awdtalontsi1992]

It is true that on older engines putting a lower temperature thermostat can help with power. This is due mostly to the cooler temperatures helping to hold off detonation slightly. However heat is actually your friend...to a certain extent. The correct coolant temperatures actually aid in the combustion process and allow proper A/F Ratios to be maintained. The heat keeps the fuel in suspension. This is why alot of modern cars have switched from the old standard of 195 degree to as high as 215 degree coolant temperatures. The extra heat from a few degrees in coolant temperature can play a huge part in combustion effienceny, engine power, and emissions.

Another reason a lower temp thermostat is not a good idea has to do with the engine management. The PCM (Fuel Injection Computer) has a certain "happy zone" where it will run the engine at peak efficiency and power. When the computer is in this zone it will allow the leanest mixture possible, most timing possible, most boost possible, and run in closed loop. One of the key perameter's the computer uses to determine if it is in this zone is the coolant temperature. The computer has a preset code from the factory that is based on the stock thermostat temperature. If you put a lower temperature thermostat in the computer's coolant temperature reading will never reach this specific amount. Thus the computer will think the engine is still warming up and will never enter the "happy zone". On some never cars this will throw a Check Engine Light. The newer EVOs actually keep the stock boost level lower at startup and raise it as the coolant temperature rises.

 

[1G90AWDTsi]

I love this forum, you guys are awesome. These are the best answers I could of possibly gotten. THANKS!!!!

 

[44pirate]

So what is the best temp to run at???????????????????

 

[Defiant]

DSMs are happiest around 210°F.