Ive heard good things about switching to 160* thermostats but i dont quite understand how goin from 190 to 160 helps. please explain cause i need a new one and i dont know which one to get. thanks

 

I don't know all the reason's but I would surmise that when your engine runs at a lower temperature that means the heat disipation from the engine would not heat up your air intake components as much and therefore the intake air would be 20 degrees cooler, and it is a fact the cooler intake air translates into more power.

 

The thermostat will open at a lower temperature so that the cooling system can start to maintain the lower temperature. If for any reason the engine produces more heat than the cooling system can remove then the temperature will continue to rise reguardless of the thermostat temperature. If the cooling system is more than adequate in removing the heat, it could lower the temperature too low. The thermostat will then close to maintain the 160* temperature.

A colder engine produces more power. An engine still needs to be hot enough to burn off deposits and keep the oil warm enough. 145* is the minimum any engine should run at.

195* is used in computer controlled fuel injected cars primarily to lower emmisions. A hotter running engine produces lower emissions and gets better fuel economy.

You can't just pull the 195* thermostat out and install a 160* and expect it to work. The car will run colder however the computer is still expecting it to run at 195*. It will run richer since the computer still thinks the engine needs to be warmed up. Aftermarket programming can change the system requirements to allow for a cooler running engine.

 

My article should help to understand this topic somewhat:

http://www.thirdgen.org/newdesign/tech/cool.shtml

 

The temperature rating of the thermostat is the opening point in measured in degrees F*. Simply put, a thermostat with a 160* rating will open sooner and remain fully open at temperatures that the 195*stat would start closing, say 190*, allowing full flow to the radiator. By itself it offers little benefit, but combined with a lower fan switching "on" temperature, it can allow you to get a cooler ,denser air charge in the cylinders and run more advance ignition lead, compression etc.resulting in more HP gains than any thermal losses.
With our cars, knock and knock-retard can rob us of some serious power, silently, and it usually gets worse the hotter we run.

It would be "ideal" to have a cool intake and coolant, hot oil and combustion chamber, so you get a large dense air charge in the cyl and then expand and explode it more quickly and completely.