My 93SSEI ran at 220 or higher in this Florida heat. After 180 install it runs at 195 on highway with temperatures over 90,but goes back to 220 in stop and go traffic. Since half my driving is on the interstate I'd say the results are a plus.

I've read so much on this forum about the pros and cons of 180 thermostats, and I still have mixed feelings. Some of my thoughts:

If the engine is designed and built to be run with a 195 thermostat, why is it better to change it? If 195 was not good, wouldn't they have changed it by now?

The age old problem of the fans still not kicking in until 220 is a pain. If you go to a 180 thermostat, then you will get much greater temperature swings while driving. And temperature changes put mechanical stress on components, more than if they just stayed at one temp. Plus if your temp keeps swinging from 180 to 220, doesn't this mess up the computer air/fuel setup? Seems to me that it will learn how to properly run at 180 when you are on the move, but then try to re-learn the 190-220 temps when you are in traffic.

I'll concede that a cooler engine should make a bit more power because of the cooler air intake, especially with a SC engine. But power isn't everything.

If you try to keep the engine at 180, then you have to throw away more heat (energy) than if you try to keep it at 195. So it must waste some fuel.

I don't see how 15 degrees can make a huge difference in the longevity of engine components. Willwren, I know you will read this and take exception. But it just doesn't seem to me that 15 degrees out of 220 makes that much difference. If you change your oil and tranny fluid at good intervals, they should be fine.

For someone like me who lives in an area where we go from fairly hot to fairly cold (Boston), having a 195 is mandatory in the winter, and I don't feel like changing stats every year. I've got better things to do.

My 94 SE sits at 195 and doesn,t go over 200, it was very uncomfortable watching that guage climbing over 220 in this Florida heat on my SSEI. I'm no auto tech but I think I'm logical. If the car was designed to run at 195 why is it running over 220. It seems to me it'* the supercharger is causing the bump in temperature and now on extended trips I'm running the car at the recommended temp.
I'm not trying to be a wise guy I just feel more comfortable now.

Great discussion, Will.

How the heck do you get such good mileage? I get 20 MPG around town and at the most 23 MPG highway. And I am definitely not running rich.

I'd like some others to weigh in on mileage for SC bonnies.

The thermostat will keep your car at 195 as long as the vehicle is moving, to pass air through the radiator. When you are in traffic, the fans don't come on until 220 degrees. At least that is my understanding.

Hey good discussion Guys !! It'* pretty good to exercise the old brain on stuff like this, huh !! I think I remember hearing recently that mental exercise helps to prevent the onset of Alzheimers (sp?),, -or was that prolongs the onset,,, I don't remember

Needless to say, I find these multiple discussions on thermostats, engine temps, etc quite interesting, especially from the stand point of, "well, whatever."

I hope that most everyone realizes that today'* engines are totally safe and happy operating anywhere within the 200 to 225 area. In fact, I'm rather suspicious that as time goes on, we may see OEM design temperatures even higher.

Say, TelePlayer, very good point on the temperature swings !! My day job involves operation and maintenance of multiple cabinets full of hundreds of large electronic circuit cards. The single largest enemy to the long trouble-free life of these cards (-in fact the whole system) is changes in temperature. -especially rapid changes. The manufacturer even has a graph that specs the absolute maximum "rate of change" allowable. The equipment can actually operate quite well over a fairly wide range of temps, but the REAL KILLER is changing temps, especially too quickly.

So by now everyone says, "what the heck does this have to do with our engines!" Well, maybe not too much, other than both are using more & more plastics as the years go by, and it seems kind of suspicious that neither one is reacting very well to temp changes.

You know, purely for the purpose of good mental exercise, I'd like to introduce some very intersting research that has been done on several different automotive engines (some very high performance, even) that have run WAY WAY HIGH operating temperatures. It is interesting to find that the horsepower output went way high, the fuel consumption went down, and emissions went down too. Isn't that something to ponder. Of course, one of the most limiting factors right now is the survivability of the engine oil, which is fairly happy around 250, but not much higher.

Hey, always enjoy the privilidge of "chiming in." Keep up the good "brain power".

Let me start by saying that a lot of this is fairly new information. Many of you may know I used to use a drilled 160 t-stat but haven't since the cars completion and do not plan on going back to it. Just don't want to look like a hypocrite. That said....

There'* more to the thermostat than just emissions and a cooler thermostat may actually cost you longevity. I haven't had my coffee today but let me try to explain anyway.

Two by-products of the combustion process are carbon and water. Both of these make their way into your oil pan and accumulate. If you've ever dug deep enough in your engine you'll have noticed sludge, point made. To combat this engine manufacturers decided that an engine needs to run at or near the boiling point of water, thus the industry standard 195 thermostat. Having the engine run at this temperature helps to boil off the water and keep the sludge from clogging oil pickups, oil passages, and other important areas of the engine.

Since this has become the standard temperature oil refineries produced gasoline that vaporizes more effeciently at this temperature. This is a bigger issue with TBI and carburated engines where too low of a temperature can result in gas dripping into the runners and not be evenly distributed. This is where the 'you'll fail emissions' statement came into play. OBDI (and II, although it has other qualifiers too) computers require the temperature to be 160 degrees to go into closed-loop and turn on its emissions regulation sensors so this isn't really an issue with modern cars.

Point being, if the potential for 0.5hp is worth possibly causing catastrophic problems with sludge forming then go for it. The rest of you might want to invest that $10 in gas. JMO

Let'* save the do you leave on or turn off your computer to another day. I turn mine off.There are not many days where I live that the a/c is not on. My understanding is the fans go on w/a/c.
As I see it the 93 and 94 now run at the same temp on the interstate.
Maybe it'* like it seems a clean car runs better, it seems to run better on interstate at cooler temp.

Virtually every mod on my car increased power AND efficiency. The engine struggles less now. The intake, exhaust, cooling, and chip all increased my fuel mileage in small steps. As long as I keep my foot out of it. If you don't USE the power you gain, it translates to efficiency.

Even the smaller SC pulley didn't negatively affect my mileage.