Originally Posted by Jim Taylor

I did the lower thermostat/fan settings soon after I got my car back in 2000. Driving around here in DFW weather (hot summers, mild winters), they do nothing for my operating temp. The cooling system can only do so much, and the car runs as hot as if I'd left it stock.

Originally Posted by BAD_TCR

...So, yes theoritically, your lower stat will reduce temps as the engine works creating more dense air, which will equal more power. Is it a lot? No, not really,... Do you benefit any other way? Only, in your mind, because yes these engines were designed to run hot,...

Originally Posted by 502ci

Try running your car at the dragstrip with the stock thermostat then run it with a 160 degree thermostat and lower fan settings. Your times will be all over the place (stock) and much more consistant (with the 160). Not to metion .10 quicker which eqauls 10-15 h.p. I`ve put a 160 in all of my performance cars over the years and swear by it, and I have heard every opposing view.

Originally Posted by Warp Factor

The biggest benefit is probably with forced induction, where lower temps make the engine less likely to detonate.
Might also allow more timing (and power) normally aspirated with a retune.

Originally Posted by MeekRN

if your driving in a race, you can dump dry ice on the intake manifold which will lower temps and give more power, if your trying to out think GM, its a lost cause. the LS1 is designed to run 4000rpm for 4000 hours straight, and it does it without failure, infact some airplanes are adapting the LS1 to planes (which will include A/C). the typical aircraft engine which produces 350 hpr costs about 50K. 7000 for the LS1. to have said $50K engine rebuilt cost more than a new LS1...

Originally Posted by EHS

Why didn`t GM put it on at the factory then?

Originally Posted by Warp Factor

Probably fuel economy and emissions.

Originally Posted by jimman

This is total BS you need to learn about thermal conductivity with AL and combustion efficiency. This is no longer the 50's with cast iron engines. Check all the dyno graphs that have been posted recently all are better with the hotter temps. I just finished 50 pulls and the best are 200 plus.

I just remembered I hold a patent on Thermal Dynamics.

Originally Posted by Michrider

There are numerous engineering requirements that go into thermostat selection, not just one of needing to light off the cats soon.

Yes a cooler t-stat may net quicker times. If your building a race car, that's a good choice. Owning a street car that should last 100K and beyond, I'd lean toward OEM selection.

Even if we just went down the road of cats not lighting off soon. Any detrimental effects? What if those cats go bad and mr dealer scans the data and finds out the silly thing is never reaching proper operating temp. Mr customer gets a huge bill.

Why do nascar teams heat their oil to nearly 300 degrees? Hot oil, cool intake charge = faster lap. Instead of cooling the entire engine down with the wrong thermostat, they heat that motor and oil up and direct cool air to the intake.

The cooler engine isn't really what's making more power. It's tricking the FI system to richen up the fuel. Same car probably has also opened up the intake and exhaust and is now running lean on the factory tune - the perfect recipe for detonation. Cool the engine down to trick the computer for a richer mixture and vwalla more power because your out of the detonation and closer to an ideal AF ratio.

I think a better approach is tuning to match any mods that have gotten the engine into the detonation problem.

Ever see all the problems a lot of imports are having with oil sludging. Most of it is due to small engines that hardly generate any heat, can't burn off the condensates. So we have here a V-8 that generates nice heat, never any sludging problems, is knocking 30 - 40 degrees off it's operating temp the right thing to do. Most powertrain engineers would say maybe for a race car, but your street car came from the factory with the right thermostat.

Originally Posted by jimman

NASCAR runs their coolant in the 220 to 230 degree range. 358 cu in 800hp and run 9500-rpm's all afternoon. Cool air not cool engine especially with aluminum, thermal conductivity is so high with al vs. iron it's tough enough to keep the head temp where it should be. Long term reliability is in question not only with not burning off contaminates but short trips where engine doesn't reach temp causes shut down in a rich condition and you get cylinder wash down. This then let's you start on a dry cylinder next time out. Long trips no problem but a few thousand cold starts and you will wind up like I did with my 85 and 88 with scored cylinder walls at 70Kmiles sucking 1 quart to 500 miles. Before you all go nuts and start throwing tuner names around you might want to talk to one of the good ones like I’ve done and you will find out that the low temp therm is ok if your going to drive 1400 ft and wait in line an hour to do it.

Originally Posted by WHINER

changing the t-stat is a band-aid.
there are radiators that WILL fit.
you'll make more powerand have longer engine life at 190-195 degrees than at 160.
EVEN if you have a 160 t-stat and play with the fans, when you drive it hard or it's hot outside , it will go over 200 in a heartbeat.
with a larger radiator , mine never goes over 198 where's EVIL-TWIN ? he can explain it to you.............lol

I just gotta laugh at weekend warrior mechanics

Originally Posted by WHINER

When I foolishly tried that 160 stat with a stock RAD. I ran 220-235.

With a 190 stat and a real RAD. I run 198 max no matter what.

Go figure it out .

Originally Posted by WHINER

too cool also can COST you power
you want cold air, not cold motor

Originally Posted by SickRick

Aside from all the cool scientific explanations/justifications posted here, the fact of the matter is, that the engine runs in the +190 range normally - above the opening temp of the thermostat, whether OEM or the lower temp one.

The only thing a lower temp thermo will do, is open the block to the cooler coolant in the rad SOONER. The engine is SUPPOSED to run at operating temperature - mine gets there in under 5 miles here in SoFla. So regardless, the 'stat is going to be OPEN anyway.

In COOLER climates, the thermostat allows the engine to actually GET TO operating temps sooner, as 30* weather is going to keep your coolant temps down alot better than the 90*+ we get here in SoFla 11 months out of the year.

These engines are designed to run at the 190+ mark. Whether the 'stat opens at 160 or 185, it has NO EFFECT on temps once the engine reaches DESIGNED OPERATING TEMPS - as it's wide open anyway.

Rick

Originally Posted by BAD_TCR

Some one must have did you wrong then cause I run a 160 T-stat all year long in the DFW area and the temp drop compared to stock is signifant and noticable. Normal car moving temp now is around 180-186. Traffic/stopped is around 200-205. Definte change from stock!

I also monitor my oil temps as after all it is that oil/engine temp that really matters....and I have no problem reaching 219F in my driving with a 160 stat, even while the coolant stays at a lower temp, but I do drive 30 minutes as a DD with a lot of lights in the city.

So, yes theoritically, your lower stat will reduce temps as the engine works creating more dense air, which will equal more power. Is it a lot? No, not really, but a tuner is going to recommend it. Do you benefit any other way? Only, in your mind, because yes these engines were designed to run hot, but it always got me so worried and nervous to see my temps climb. Now with the 160, I never worry about the temps and the engine still reaches high enough temp to do its job with contaminates. Do what you want to do, take into consideration the climate you live in, driving habits, etc...whether you are getting it tuned and want to do any other mods, etc...