
Originally Posted by
Daox
A lot of guys that turbocharge their engines can keep the stock radiator without any issues at all until they are running waaaay higher than stock horsepower. Seriously, most cars have massive cooling capacity compared to what they need.
Going to a cooler thermostat isn't going to do anything unless there is a hot spot in the engine (which there shouldn't be) and you're getting knock. Most newer vehicles are running warmer thermostats because it increases the engine's efficiency (gas mileage and power gains). Unless you're getting problems with not being able to advance your ignition enough (usually fixable with higher octane fuel) or getting knock I wouldn't recommend going to a cooler thermostat.
If you're looking to mess with engine management you should be monitoring things like coolant temp, air intake temp and many other engine sensors. If you find that your coolant is getting too warm while tuning only then would I even think about upgrading the cooling system.