1967 Yenko Clone

Is everyone running t-stat. I have 186 stat,my fan turns on at 200 ...so how can the fans every turn off? I think the fan turn on should be higher? WES

fast400

iTrader: (1)

You can adjust this in your pcm. Why would you want the car to run hotter?

crainholio

iTrader: (2)

Hot chambers deliver more power, proven engineering fact.

Obviously there are limits, and an optimal temp after which detonation becomes an issue, but you'll make more power than overcooling.

fast400

iTrader: (1)

That optimal temp is nowhere near the plus 200 water temp he's looking for!

NoClassic

iTrader: (42)

If your water temps are hovering around 200 that is fine.

You need to consider that your oil often 20-30 degrees higher than water temperature.

crainholio

iTrader: (2)

Really? What is the optimal coolant temp for power production on an LS1?

1967 Yenko Clone

What is the temp i need? My thoght was if the stat is 186 and the fan turns on at 200ish,the fan at idle not moving will always be on.? I thought the factory turned on at 225 of at 200ish. See what i am after. The car does not run hot. I don't like the fan on all the time at idle. Thanks Guys Wes

dsrour

adjust fan turn on temperatures. Thermostat really does not effect steady state operating temperature. Factory settings are ~235 turn on temp.
I have mine set 226 on 219 off.

RE AND CHERYL

iTrader: (31)

I set my temps on at 210 and off at 195 and never heard them on at a stop unless I was in traffic.

Re'

crainholio

iTrader: (2)

Sounds like you're using the dash temp guage as your indicator of fan operating temps, not a very accurate way to go about it.

You'd want to use a scantool and see what temp the PCM is seeing when it switches the fans.

1967 Yenko Clone

I am using a mech temp that is in the block. The computer is done by Howell. The scan tool indicates that my thought process is correct. There is 20 deg. difference between the heads and block. My problem(if it is a problem)is that once the fan is on IT WILL NOT TURN OFF. It does not overheat,but i feel the on/off is wrong. stat 186 turn on 200 4 degress difference? Thanks again Wes

DRGnFLYZ28

160 thermo with fan turn on at 190 for my setup.

1967 Yenko Clone

With a 160 stat what does it operate at. On a Ls how do you chace the stat? Wes

ryanvv355

iTrader: (17)

160's operate at about 175-185, my fans turn on at 190 with my 160 stat

rsz288

Dead right there man! This knowledge has been around for decades amongst the top end engine builders, backed up by coated piston crowns to prevent heat loss, just as a higher (the right) coolant temp reduces combustion heat loss. But still lower opening thermostats are used so often in the search for "power". :doh:

Wes: what is the scan tool showing the temp at, based on the stock GM sensor location? Which is the front of the RH head.

Rodder

iTrader: (2)

It's a balancing game, with thermal efficiency on one side, and volumetric efficiency and detonation on the other side. The plastic intake manifold reduces the impact of higher coolant temps on volumetric efficiency, and the fast-burn combustion chambers reduce the impact on detonation.

2002 SS HUGG

Hmmm...are you building a top fuel racing engine, where you need every little extra hp at all costs??? If not, then I'd just recommend going with a 160 thermostat and setting your fan switch to come on earlier and call it the day...but perhaps that's just me. Good luck with whatever you decide to do man.

Pop N Wood

iTrader: (1)

I thought coated pistons helped the engines run cooler? In non-turbo applications they aren't really to stop heat loss, but more to prevent the pistons from absorbing heat and thus leading to detonation.

I know Government Motors sets the LS thermostat settings so high for smog reasons. Must have read that a 100 times. But I have also *heard" that LS motors make more power the cooler you run them. A cooler motor allows more agressive tuning, and that is where the power comes from. No Carnot theory needed here.

Not trying to start a flame war or one up anyone, just wondering whether a cooler thermostat is better or not.

Any one done enough dyno testing to answer without speculation?

fast400

iTrader: (1)

Thanks SS,
That was the point I was trying to bring across...I got slammed...

rsz288

Apologies if it seemed you were being slammed. No intention here to be a slammer, or you a slammee . Certainly a very interesting position on the optimal temp for an LSx engine and am hanging to hear more on this.

At one point in time it was proven that iron SBC's produced more power up to around 220F coolant temp. The higher coolant temp enables higher thermal efficiency.

Alloy LS's potentially are a different story of course, and I for one, would like to see some conclusive info on an engine on an engine dyno (not in a hot engine bay) and how the power looked against coolant temp, all other things being equal.

Have read that some racers have found that LS's produce max power at ~180F. But! Was this with the same timing and mixture settings, or were they re-optimised for different coolant temps i.e. from say 160F through to 220F.

Why? To answer the question of what less timing and leaner mixtures return in what is a (theoretically) thermally more efficient scenario with higher coolant temps. If an engine is tuned close to the edge timing wise, and coolant temp is increased, it will lose power!

An alloy engine loses heat faster than an iron engine (one contributor to higher comp ratios ?) and higher coolant temps should reduce this heat (power) loss. (in theory at least )

On running lower coolant temps, and speaking from years in the game, if an engine has been run a lot of its life at factory specs, say 200-220F for example, which is a design temp, and clearances are "worn in" at this temp, to all of a sudden cut coolant temp by 20F or so, means the operating clearances will change, i.e. piston to bore doesnt quite make it, bore "roundness" doesnt quite make it, blah blah, then oil consumption does tend to rise.

If an engine is built with 180F coolant temps in mind, and run from the get go at that temp, thats potentially a different story.

(And last time I looked, fueler motors didnt run coolant. Well not in a water jacket anyway. Nitro, run time and engine life seems to look after that angle. )