here is an interesting comparison

http://www.superstreetonline.com/how...ke-more-power/

 

A 160 stat in a LT1 is about the same as a 180 in a standard SBC.

 

I agree. Good read.



Huh? Isn't there a 20˚ difference between the two?

 

I guess because you're cooling the head first but I still don't get it. I would think it would be the other way around...

 

The Lt has a lower rated stat because the coolant goes through the heads first and then the block as you know. They call that a reverse cooling system, when the stat opens it actually lets coolant into the engine from the lower hose. If it had a 195 stat, an Lt engine would run pretty hot going down the road. I'd bet it would run 210.

 

That's why I would think a 180 in an lt is like 160 in a regular flow. You have cooler water hitting the heads first so you need less of a temp gradient for the same performance.

 

I'm not following. My LT1 has a 180 stat...it typically runs in the 185-190 range...right down "against the stat". If I climb a hill, then decent a long hill temps can go as low as low 170's due to the delayed effect of the stat closing and cold water in the radiator. Anyway, it runs just above it's rated temp.

But so to all the other cars I've had, with conventional cooling; Install a 180 stat...they run around 185-190ish. I'm not "seeing" the diff...

 

You are correct, the idea it run farther above the t-stat temp with a hotter 195 t-stat makes no logical sense.

The whole point of the Lt1 was to cool the heads first so you could make more power by increasing compression and reducing detonation. Kind of flies in the face of run it hot for more power and economy. The fact that GM increased compression for better power and economy while cooling the heads to a lower temp should make people question the notion to run the engine hot. As demonstrated by GM adding compression and keeping it cool more then offsets lower compression and running it hot.

 

I have been running a 165 degree thermostat in mine for 14 years...engine still runs around 180 degrees most of the time...especially sitting in traffic.....short trips in mine too.......allowed me to throw 36 degrees of total timing at it for optimal performance at WOT w/o detonation with 10.6:1 compression ratio (static).

0 issues........

 

Cooler heads - more power - period !!!!!!! Why ??? To be coninued ...

 

Isn't this the same reason some guys run water injection?

Cool the combustion chamber and allow for more compression and/or timing?

 

Denser air doesn't hurt.

 

No surprise to me as I ran my prior '88 constantly with a 160deg T-stat to a little over 200k miles on the clock and many of those were down the 1/4 mile.

First "mod" to my current '88 was to install a 160deg T-stat...

 

IMHO - I try to run the engine at around 180 - 190 degrees. I did see a graph in some publication years ago that showed less cylinder bore wear at around 175 - 180 degrees. More temp than that didn't seem to help much. (Ill try to find that graph.)

Old school drag racers used to use "cool cans" literally full of ice - and ran the fuel lines thru these cans to try to keep the fuel and the carb cool - thus allowing a bit more dense air and a bit cooler carb to allegedly allow a touch more timing / compression.... How much was gained is obviously debatable.

I tend to think with modern oils, the difference in cylinder wall wear at 160 vs. 180 will be difficult to measure after a 100K mile life, but I do tend to like warm oil before I put heavy loads on engines. I try to get to 180 F oil temp before I start high RPM stuff (but I'm using pretty thick oil in my track stuff so I have to be a bit more careful than if I was using 10W-30)...

The factory thermostat setting is a compromise between many factors including emissions, heater performance in very cold climates, operation is very hot climates, and fuel economy. Just because the factory engineers made one set of tradeoffs - does not make it right for everyone. I'll stick with 180 - for my uses - but part of that is based on that graph I saw well over a decade ago - and as I said that may be OBE by modern synthetic oils.....

 

Good data presented, here. Thanks for those points.

 

I've heard about this graph. I've searched and searched for it. I also heard that Continental (?) engine company did some testing way back when (the '40's?). But search, I can never find the actual data; only people claiming "they heard" about these test. I've "heard" about them too....from other forum members who "heard" about them. IDK.

Based on my own experience, I agree that the diff in wear between 160 coolant temps and 180 coolant temps is meaningless. Worryin' about chit that ain't worth worryin' about.

 

Thanks to our friend "google" - I think I found the curve.

Attachment 48289158

 

Interesting.. So, the two charts say completely different things?

Looks like the lubricant may be the culprit.

 

PS: If the first chart is accurate, you have to ask yourself why we're using multi-viscosity oils in diesel engines at all?

 

No - the charts are consistent. Note that one chart is on Deg F and one is in Deg C. The First chart (the one for non-diesel) doesn't go beyond 200F (roughly 100C). The Diesel chart shows hat as you get way hot - wear goes back up again.... That makes sense! Much above 300F even synthetic oil is starting to throw in the towel.