thermostat

 

What is the big deal with installing a 180? I've never noticed it running any warmer than usual here in the Louisiana heat?

 

Lower thermostat temperature can lead to more engine wear, and provides no appreciable performance advantage. Many will disagree and cite intake air temperature, but the reality is that there is little to no reduction in the intake air temperature with a lower rated thermostat. I suppose it is possible that the computer may change other parameters based on a lower temperature reading, but it is just as likely that a lower temperature would lead the computer to back off performance to reduce wear. Can anyone show dyno proof that a lower temperature thermostat improves performance?

 

180 degree thermostat instead of factory 208 degree model
STEVE

 

I was always told that a lower tstat can allow the timing to be advanced slightly because the engine is running cooler. I fail to see how running cooler is going to rob performance or increase engine wear. Sean at Hemifever told me that it is a good thing.

 

It helps performance.
STEVE

 

The main purpose of a thermostat is to allow the engine to reach ideal operating temperature (and warm you up) faster. Running cooler means that the engine may not reach the temperature at which clearances are ideal. A colder engine is tighter and will wear faster. Any reduction in power while running cooler/tighter is probably as negligible as any power gained by cooler intake temperature and at best they would offset.

 

http://www.tuneruniversity.com/blog/...the-advantage/

 

I was about to post that very article. Makes sense

 

BBTKD... Just so your informed, this article and others like it have been "updated and modified" for there very loose interpretation on how lowering your engine temp will cause engine damage. They do not know. Tuners do know that there is a sweet spot in programing fuel and timing maps that can deliver substantially more power. I have personally written tunes and dyno tested 4th gen Camaros and my current MAX POWER tune delivered 41 RWHP on a 96 Lt1 Camaro with a 160 thermostat, intake and exhaust. Switching to a 180 stat forced less timing and more fuel and maxed out at 23 RWHP on the same dyno same day. That car has 55k more miles on it now.


There are some good points in this article but I listed some TRUE/FALSE of my own.


"The cooling system and load on the engine determines how hot the engine gets, the thermostat fully open will still be the mercy of the coolant system’s ability to remove heat" ...."Load" is the key word here

It sets a floor, not a ceiling on engine temperatures... this is true

The problem with a low temp thermostat then for regular driving is that there are times when the car will be running at a temperature lower than it’s intended..... this is false in the 180 degree range. Numerous tests have shown that 180 degrees and above range had minimal effects on engine performance with the only variations being a reduction in N0x and a slight increase in Hydrocarbons. All emissions tests performed by the PCM have already taken place and you have moved from Open loop to Closed Loop operation. At 180 the engine is fully warmed up the cat converters are lighting off and all is well.

If you’re chasing more power, this isn’t a place to look. Any power gain would be circumstantial (ie, only under certain conditions), incredibly negligible, Obviously the author has never operated a tuning program on a DYNO. If you were to look at how a PCM chooses fuel delivery, load and timing changes in their respective maps they would see that TEMPERATURE DIRECTLY AFFECTS THESE PERAMETERS. Some in a negative way and some in a positive way. For example if a durango is pulling a heavy load up a hill and the static engine temperature is 205 degrees the PCM would command a particular fuel, timing value based on LOAD, Temp, Volumetric Efficiency, Throttle Pct ,IAT, Transmission Gear. etc. Now assume the temp rises to 235 degrees as happens in this type of situation. Suddenly the knock sensor notifies the PCM of increased cyl pressure at this temp(235), the fuel map changes, commanding a richer mixture to cool the cylinder, both the IAT and Temp sensor read the higher temps prompting the Timing map to retard timing fighting to quench the detonation ( go boom ) and alas you have effectively lost horsepower when you need it the most (rich mixture and timing retard). YOU ARE NOT GAINING HP WITH THIS MOD! YOU ARE IMPROVING THE PROBABILITY THAT YOUR PCM WILL CHOOSE A MORE POWERFUL FUEL AND TIMING MAP.

and at the risk of accelerated wear on your expensive engine internals (especially in street cars)....

That is the funniest crap I have ever heard. Maybe running without a thermostat at all. These new engines /computers are all designed to get to operating temperatures (closed loop mode) as fast as possible for the good Ol EPA Smog. If you were to run your engine cold under 165 degrees you will run rich and possible wash oil off of the cylinder walls causing some wear over a long, long period of time but the PCM at that low temp would always be commanding a leaner mixture from the o2 sensors which would probably denote any wear. As long as you are in CLOSED LOOP MODE YOUR CAR WILL NOT Chew itself up.

Bottom line. You can safely run a 180 thermostat. You will be less likely to lose power due to detonation when in this temp range and as a bonus your radiator hoses will last longer....


Here are some good, real life, actually made of paper books that will give some insight by Tuner/Engineers some of which actually designed the Lt1 Ls1 engines. There is info on manufacturers testing of engine wear under different operating temperatures and why there are compromises which they are forced to implement for Emissions reasons.

Corvette Fuel Injection & Electronic Engine Control: 1982 through 2001. Updated for 2008
Charles O. Probst 8

Performance How-To: Engine Management; Advanced Tuning Manual
By: Greg Banish