GM LS Thermostats

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I am talking with a tuner about my avalanche, that i use for towing. He is recommending that i install a 160 degree thermostat. I know that probably allows him to run more aggressive timing.

I am hesitant to do that. I might consider a 170 thermostat. I think stock is 187 degrees. I'm not sure that 160 is a good choice especially for winter , and i would worry about how the cylinders would wear with the block at only 160.

Should i worry about running a temp that low?

Thoughts?
 
I don't think that I would do it. I don't see where there would be a benefit.
 
I have a friend that puts a 170 in all of his trucks. Makes everything run cooler, including the transmission.
 
Originally Posted By: fields
I have a friend that puts a 170 in all of his trucks. Makes everything run cooler, including the transmission.
Originally Posted By: xxch4osxx
I wouldn't do it. Running that cool might cause the ECM to run in rich mode constantly.


170 i might do.

The ecm will be a custom tume, i'm worried about the mechanical effects of running that cool all the time.
 
I had a 2001 supercharged Pontiac Bonneville, where some recommended a 160* t-stat. I tried it once, it set an SES light almost immediately (coolant not up to temp code) and ran rather poor with especially poor gas mileage. I believe the ECU stays in open-loop with that code, where it reads fuel enrichment off a map, instead of using the O2 sensor feedback. I quickly tossed it and tried a 180* stat. With the 180, I didn't get the code and the car performed acceptably but with less than average gas mileage.

Some months later, I took the car to Ohio to get custom dyno-tuned and the ECU programmed, by a company that specializes in the 3800 V6. They said a 160 t-stat is worthless, and the 180 can be of some benefit if the ECU is tuned for it; on a stock car they suggested using the stock 195F thermostat.
 
I've seen several engines run cool with no side effects related to longevity, but I'd be concerned about efficient combustion with a T-stat that cool, not to mention CEL's, etc. It's just me, but a 30-degree cooler thermostat to accomidate a tune sounds like a band-aid.
 
There is NO benefit at all to running a 160 t-stat in an engine designed to run in the 190-210 range.
 
Originally Posted By: Traction
There is NO benefit at all to running a 160 t-stat in an engine designed to run in the 190-210 range.


Nonsense. Wildly platform specific and depends if the tune is altered correctly.

With all the variance and subtleties in programming across many different mfgrs you simply cannot be so specific.
 
Originally Posted By: Alex_V
I've seen several engines run cool with no side effects related to longevity, but I'd be concerned about efficient combustion with a T-stat that cool, not to mention CEL's, etc. It's just me, but a 30-degree cooler thermostat to accomidate a tune sounds like a band-aid.


And it probably is, on that car. Many platforms are hard to get much out of, they are already set up well or the tuner world does not accommodate them.

But just for kicks, let's talk about my 6.1 and a cooler 'stat. This cars programming kills timing like crazy at above 180 degrees. If you run just any 180 and can't alter the fan settings then you are correct: No real benefit.

But, if you run a Moto-Rad 176 and set the myriad fan settings to the correct temps you get an engine with a completely different personality, much snappier and responsive. This also reduces the KR values significantly. Cylinder bores and oil still get hot enough to reduce wear and engine life is unaffected.

This is why it's called "tuning", it requires specific care related to your individual vehicles quirks...
 
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I was curious why the OE's don't use a 160 t-stat in everything if it works better by keeping the engine cold? Seems like it would take much longer at the lower coolant temp to warm up all the mass of the engine, plus the oil. I never hammer down on any engine until it is 180 degree plus.
 
Originally Posted By: Traction
I was curious why the OE's don't use a 160 t-stat in everything if it works better by keeping the engine cold? Seems like it would take much longer at the lower coolant temp to warm up all the mass of the engine, plus the oil. I never hammer down on any engine until it is 180 degree plus.


GM in their V8's run at 205-210 all the time! The benefits are real improvements in fuel economy and long engine life. Run those cylinder bores too cool and the wear goes up fast. With modern oils it is much more difficult to run them too hot (as far as wear goes). Of course the real goal these days is whatever mpg they can eke out of the platform.

There is huge variance in tuning strategies across platforms. Even within the same mfgr. So you must know those specific subtleties in order to tune for power without harming your engine...
 
Originally Posted By: SteveSRT8
Originally Posted By: Traction
I was curious why the OE's don't use a 160 t-stat in everything if it works better by keeping the engine cold? Seems like it would take much longer at the lower coolant temp to warm up all the mass of the engine, plus the oil. I never hammer down on any engine until it is 180 degree plus.


GM in their V8's run at 205-210 all the time! The benefits are real improvements in fuel economy and long engine life. Run those cylinder bores too cool and the wear goes up fast. With modern oils it is much more difficult to run them too hot (as far as wear goes). Of course the real goal these days is whatever mpg they can eke out of the platform.

There is huge variance in tuning strategies across platforms. Even within the same mfgr. So you must know those specific subtleties in order to tune for power without harming your engine...


Can someone show that lowering coolant temp to 160 degrees increases engine wear rate? I do know that most all Marine thermostats are set at 160 degrees!
 
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