Thermostat

I read that a thermostat for a 1991 talon tsi should be opening at 190 F. If i get a thermostat that opens at 180 F will it still fit?

Does the size matter depending on the opening temp. of the thermostat?

The opening temp of the thermostat has nothing to do if it will fit or not. A 180F thermostat will work in your car but it has to be made to fit your car.

This is just like any other part for a car. They are made specific for each vehicle

The opening temp of the thermostat has nothing to do if it will fit or not. A 180F thermostat will work in your car but it has to be made to fit your car.

This is just like any other part for a car. They are made specific for each vehicle

Yup. Also if you live in a place where there is no freezing weather you can yank the thermostat out and run freely. This is only ideal for warmer climates as with cooler climates where a heater may be required , it will keep the OT so low your heater will only blow cold air.

Also if you look around on the net you can get direct fit thermo's with varying opening / closing temps.

Yup. Also if you live in a place where there is no freezing weather you can yank the thermostat out and run freely. This is only ideal for warmer climates as with cooler climates where a heater may be required , it will keep the OT so low your heater will only blow cold air.

Also if you look around on the net you can get direct fit thermo's with varying opening / closing temps.


This is a very BAD idea. Do not run your car with out a thermostat. The engine is design to run at a certain temp range and when you change that to much it will make your car run bad. Your car runs richer when the motor is colder so taking out the thermostat could make you run rich for a longer period of time trying to warm the motor up.

I have also heard that if the engine has been running for a long time considerably under the temperature it was designed to run at, moisture can begin to collect inside the engine. When the engine heats up that water is evaporated. I know last summer during out heat wave in SC I took my thermostat out just for the hell of it to see if I'd run any cooler. The data logger proved that to be wrong. I ran at exactly the same temp on the interstate with or without a thermostat.

This is a very BAD idea. Do not run your car with out a thermostat. The engine is design to run at a certain temp range and when you change that to much it will make your car run bad. Your car runs richer when the motor is colder so taking out the thermostat could make you run rich for a longer period of time trying to warm the motor up.


I run all my cars in summer without thermos and with during winter. I ran my eclipse for about 2 months this winter without the thermo and I didnt notice any difference in warm up times. The only thing I noticed changing was how cool the engine runs when flying on the freeway =)

Lots of people will argue the matter that a thermo is good and lots will argue a thermo is bad but I stand neutral on the matter. It serves its purpose when needed and is pointless in 110 degree weather.

If you want to run cooler than put a lower thermostat in the car.

Will my car run better if i run cooler?

Will my car run better if i run cooler?

Depends on how much cooler. If it's too cold, you run richer which is not good. Normal temp is what ~200f? It's good to run no less than ~190f or so.

Will my car run better if i run cooler?


Your car will run better if its colder only to a certain extent. Like Dave said if its to cold its going to hurt performance.

Your main concern with the cooling system should be how well will it keep the motor cool on hot days and during hard driving. You cant expect to gain a whole lot of HP by running the motor cooler, but having a motor that gets hot after a few passes at the track will hurt performance a lot.

Your intake temps and intercooling will also loose you some HP if you start to heatsoak it.

That's why it's better to run with more flow into the engine bay. That way the actual motor is at the proper operating temp, but when you are driving or making passes, the air blowing in cools down all the bay, piping, and everything else in general. My temps dropped some after I striped out the A/C and basically made the front grill only have a high flow radiator. I hope on the expressway and watch my temps drop ~5-10 degrees (wind is a factor) on average. Then, make sure your header or exhaust or whatever is wrapped in header wrap and that keeps the bay cool too.

how about me running a 180F on my 91 tsi?

Although it's suppose to be 190F.

I personally don't like the idea of running without a thermostat.

The 180 tstat mod is a very common one, you won't have any issues with it. And there are direct replacements in that temp rating, though I forget which vehicle it's from...

KEEP THERMOSTAT PERIOD
Also because if the vehicle never reaches the temperature that vehicle will not go closed loop. when its in closed loop means the pcm starts to adjust a/f by the o2 sensor. if it never reaches operating temp it will stay open loop and just go off by fuel maps it has stored, just like when you go WOT. goes into open loop. so its bad.

and as for obd2 vehicles when tested for state inspection (SMOG) the vehicle never runs its monitors because of never reachin operatin temp and will fail obd readings for state testing in some states.