Has anybody doen some experiments with engine temperature and power on the LS1 engine? Assuming the VCM is adjusted correclty would a lower running temperature produce more power?

 

Exact opposite , as most nascar teams found the hotter you can run the engine and the lower you can get intake temps the more power will be made , We found at Orbital when we were developing the engines for emmision we got better fuel economy and power ans well as improved emmisions the hotter we ran the engine.

The cold thermostats are a hang over from the early days of efi when by running a cooler thermostat the engine was tricked into running richer and had more ignition timing , nowdys we can program the desired mixtures and timing.

 

Hot engines with cold intakes... Thanks for confirming that!

 

BUT, for those of us road-racers, you have to keep the engine cool (via thermostat/fans and anything else) as long as possible, as once you get up to speed, the temps often go off of the chart anyway. Oil temps, even with coolers, can get into the high 200's easily, and over 300 in a stock car with no coolers at the road course.

 

but for the street and strip, keep your stock thermostat.

 

I disagree. With cars that I have dyno'd and the cars on the track (I am talking about LS1s) the best dyno and best ETs come with lower IAT and between 175 and 180 degrees ETCs. They lose a little bit of power over 190 degrees.

 

I had a little automotive epiphany whilst boiling
some water.

There are a couple of limits to the power you can
make in a liquid cooled motor. The coolant boiling
is one but closer-in is the cylinder / chamber wall
temp you can rub up against without uncontrolled
ignition. This temp is all about the worst case hot
spot in the chamber. It has to be below a critical
ignition temperature.

Now, the wall of the pressure vessel has thickness
and thermal conductivity. That means a temperature
rise across it, when conducting thermal power. As
from combustion to coolant.

Starting from a fixed Tmax at the surface (coming
from mixture composition, compression) to not
diesel, the more power you run the lower the temp
at the cold face has to be, to remain safe. Simple
thermal conduction. High performance motors are
maximizing peak pre-ignition cylinder pressure. That
is the goal. That lowers the allowable ignitor temp
I think, the mixture itself is hotter.

The guys chasing high efficiency want to go the
other way, hot charge, they do not push enough
waste thermal flux through the walls to elevate the
wall temp. Running low speed load, you could overcool
so a high temp 'stat is dandy.

 

What about the "cooling" line that runs through the throttle body?
I assume it is there to stop the throttle body from freezing, but at higher temps it would be heating the intake air.

Any HP to be had by disconnecting it? We never see sub 50*F temps where I live.

 

FWIW...
I have had a disconnected TB collant line a long as I have owned the car...adn I haev been through "4" sub zero winters with no ill effects from the TB coolant bypass mod....

an I have always had better track times with my stock thermo then when I tried the 160 and 180 stats....also made more power on the dyno...fan temps were set to kep me in the 200ish range when I was laying into it creating the most cylinder heat

most of us are burst racing...not road course racing our cars...so the hotter thermostat is keeping us below the pre ignition from heat point..again.as long as the fans are set correctly...