ELEVENS

Don't you just love a good thermostat discussion?

AGENT 86

Well iv'e sat back and watched this post grow. I have a 160 stat and chip to run main fan on 174 off 160. It's been 90-100 degrees here for the past couple of months and my car runs 165 hwy and upto 185 city.Normal city traffic i see about 172. Obliviosly i don't see below 160 and i don't run in the 200's so i think this setup works great. :D
:cheers:

dizwiz24

No problems with my 160 t-stat. My car runs around 174 in 90 F heat.

Before, it ran at 210F, even 230F (WOW!!!!) in summer time heat.

I do have an Ed Wright custom chip too.

drumboytroy

:iagree:

gcrouse

JFB already knows this, so the rest of you need to memorize a few fundamentals:

210-230&deg is normal for a C4 and your engine is fine; 250&deg is hot.

The thermostat RESTRICTS water flow out of the block. This increases pressure and keeps millions of tiny air molecules dissolved; lest they get together and form air pockets which push coolant away from cylinder walls and create hot spots, which then cause more coolant to vaporize, etc.

The thermostat sets MINIMUM engine operating temp. When closed, it prevents coolant from circulating so it can't lower the engine temp below that point.

Achievable operating temp is a simple contest of heat generated by the engine vs. heat rejection of the cooling system. IF it's cool enough outside, and IF your system is actually capable of shedding enough heat to reach 160&deg, then a 160&deg, 180&deg, 195&deg themostat will set that as the MINIMUM engine operating temperature.

If however it's August in AZ and your car is running 230&deg, it's because the cooling system is maxxed out and cannot shed enough heat to lower the temperature any further. And a 210&deg, 195&deg, 180&deg, or 160&deg thermostat won't make a damn bit of difference under those conditions.

And engine temps don't directly affect power that much; it's much more dependent on intake charge temps (which determines air/fuel density.) However, too cold an engine increase friction; too hot can pass heat to the intake charge via the heads and manifold.

You guys in search of a couple more hp need to realize that 160&deg is just too cold for a modern engine to run. You need 180&deg MINIMUM so the oil's hot enough to burn off condensates, and cylinder clearances are adequate to minimize wear. Find it somewhere else like with pulleys or something...

ELEVENS

Mr. gcrouse:

Amen Brother! You da Man!


[Modified by ELEVENS, 8:41 AM 8/18/2003]

HiRiser

FWIW, I took out my 160 and it is on the shelf right now. It was too cold running up and down I5 to/from LA.

I put in a 160 since I suspected a thermo problem. There was. The OEM thermo was only opening halfway( tested on stove) Put in the 160 anyway, and as I said, it was too cool. Running a chevy parts counter thermo now with no issues.

Your results may vary
:cheers:

Strick

Let me see if I can sum it up. We all agree that the Tsat opens at the temp it was designed to open at. Once it is opened, it has no more control of the coolant temp. Most of us are still semi-stock in our buildups, which means the running temp should be around 200-230. The radiator is designed to cover that range as well as the rest of the system. What causes our LT-1/4s to run out of that range? I would guess that it is something in the cooling system that is not working as designed. And, the possibility exists that another mod might have changed the demands of the cooling system. What we try to do is improve. It seems that the best improvements in the cooling system are 1) a better pump, 2) better radiator, 3) better control of the fans, 4) clean radiator, 5) good coolant, 6) good pressure cap, 7) well maintained hoses, and 8) no leaks. This was an interesting thread, but the cooling system is really easy to understand and maintain. :chevy