Has anyone done a Horsepower comparison between a colder T Stat to a hotter T stat??? My car seems to run better with a 160* stat. I like to stage with the temp around 150* before the burn out.

I have done back to back runs testing this. My car is a tenth faster if I hit the burnout box at 140 vs 160. My car gets fresh air via tunnel ram through the hood so there is very little(but not zero) impact of engine coolant temp vs air inlet.

I don't run a thermostat but I change my fan settings at the track to run way cooler. I don't even turn the fan on until 180 for the street.

Warm oil in a cool engine was the old racer's maxim. But that was a long time ago.

The tune could have a lot to do with which temp your engine seems to prefer. There is more wear at 160* than at 180* if that matters in this case. 180* is a very good operating temp for our engines as far as wear. You may try experimenting with the carb fuel rations to see if you can find that extra performance at 180* that you have at 160*.

And then little things like incoming air and fuel temps may also be at play. Does either temp come up with the engine temp? Timing and octane needs may also come into play as the temp changes. Can you solidly maintain 180* or does it tend to creep up? And don't forget to consider the ambient air, too. Lots of pieces to the puzzle that should be considered.

The only way you will know what YOUR combo likes is to experiment.

My street/strip cars show no performance gain at 160*. But I have them tuned for 180* and they can maintain that temp in most conditions.

I have experimented with 180* T Stats. As I said, MY CAR, runs better with a 160* Stat. My car is mostly street driven. With the hottest days of summer, my engine temp never goes above 165*. I was just curious as to what others have had experience with different temps.

Reher Morrison has a good article on this. Colder is better according to him.

Cold motors wear faster than hot motors due.

The wear issue seems to me avoidable by getting the oil hot enough to burn off condensation and fuel contamination.
There shouldn't be much fuel in the oil in a properly tuned engine.
That's one reason for the warm-up off the trailer, and/or more frequent oil changes than a street car.
My Duster ran best with warm oil, and water temp 120-150 pulling into the burnout box.
At 350-400 passes, everything inside including bores & bearings still looked fresh.
Street cars are a different deal, of course.

180 degree coolant and 215 oil temperatures have to be optimum for power, says Marlan Davis

https://www.motortrend.com/how-to/hrdp-0910-piston-ring-tech/

sample quote

Control windage with a sophisticated oil pan and windage-tray setup. With a now-tight bottom end, you won't have oil flooding the cylinder walls, so a power-robbing high-volume oil pump is no longer required. Marginal engine coolant systems will no longer cut it, either; consider coolant system enhancements. For a nonemissions performance application, shoot for 180-degree F coolant temperatures and 210- to 215-degree oil temps. Get your carb and ignition dialed in right; washing down the cylinder walls with fuel isn't good for ring longevity. Combine all the tricks and details and the result will be more power.
end quote

My fuzzy memory is that one of the Aircraft Engine Companies did the first scientific study of cylinder bore wall wear versus coolant temperature and found that 180 degree was the lower wear minimum. I seem to remember Continental, although today they most make air cooled engines.
I think the bore wear graph in the link below comes from that older study.

http://www.carnut.com/ramblin/cool3.html

My interest in the “best” coolant temperature comes from an old link about year 1997 on the Evans Cooling website where one of their customers wrote he had done both dyno and personal vehicle tests at 260 degrees F and found fuel economy gains. This customer claimed to be employed at Ford as an engineer.

I searched for and failed to find a thermostat higher than a Robertshaw “Balanced Flow” 212 degree to put in a 1995 Magnum 5.9 V8 using Evans NPG.
Two one day/next day back to back identical 200 mile tests over I-40 between 180 and 212 thermostats showed a tiny 0.3 MPG improvement at 212 F,
but I now realize wind speed, wind direction and air temperature changes make that statistically insignificant.
It would take two pickup trucks traveling “convoy style” in a TMC/SAE RP1109 Type IV Fuel Economy Test Procedure rules for a two vehicle fuel economy test over maybe even longer than 400 miles to detect the real “statistically significant” MPG difference.

Later that Robertshaw thermostat failed in the closed position with NPG as coolant and I had to drive about 12 miles with coolant temperature showing over 250 degrees, but had no detectable damage.

Later still with a new working thermostat installed I did experiments with no fan attached to the viscous clutch.
One of the first experiments was to idle the pickup in park with no fan for several hours.
The dash temperature gauge showed a bit over 250, and the interesting thing was that idle vibration became very very smooth- much better than stock.

While driving without the fan on I got stuck stopped in a huge traffic jam on I-75 in Atlanta in 80 degree F weather.
The coolant temp went way high, but the engine idle was smooth, and the air conditioner was still blowing cold air.
But... after about 20 minutes I “chickened out”.
I turned off the AC,
turned on the heater at full blast instead, ( like Cannonball Run movie)
and rolled the windows down.
Got rolling again about 2 hours later.
No detectable damage.

It was Continental Motors, not aircraft, about 70 years ago

sample quote

h. I recreated the graph from an old engine textbook so it isn't perfect but it's very close. The only details I have about the test is that it was run for 60hrs and done by Continental Motors. The book is copyrighted 1986 so the test is at least 20 years old.

end quote

http://www.robroygregg.com/Number50/CylinderWear_Temperature_z.png

another interesting chart:

https://www.offshoreonly.com/forums...igh-oil-temperature-wmoil-temp-chart.jpg

If you run high coolant temperatures perhaps you need an oil temperature gauge

My junk does best when I pull in the water right at 160. By the time I burn out and stage it's at 170. Make the pass and by the time I get back to the trailer it's betweeen 190 and 200.

Engine Masters tested and it was about 2% increase from 200 to 135 degrees on an 800+ HP big block Chevy.

Thats with no manifold heat, in a dyno cell. Depending on your application I think the temp difference could actually make a bigger difference. Fuel temp can make a big difference, and intake air temp will make the biggest difference. If these factors are no isolated your underhood temps will impact power alot. But exhaust temp is going to be the biggest contributing factor in most cases.

My feeling for water temp is 140-160 is probably optimal for power. 195+ is for nothing more than emissions, you can see the evidence of this by just looking at Chrysler engines from 1967 to 1968. In ‘68 (fed emissions break in) they went from 180 t stats to 195.

180 was most likely already a compromise between longevity and power output.

It's worth mentioning that race gas is different from street gas.
My previous comments refer specifically to 110 race fuel in my 13.0:1 SBM.
That said, I've seen the same results too many times to count, all racing engines.
Seems logical & quite likely that street gas is formulated for warmer running temps.

The many NHRA Stock and Super Stock racers who use chillers to lower their engine temps to 50 degrees or so before heads up runs may disagree with Mr. Davis.

Look at the gauge many of them use...

Has no one noticed that the OP said that his car is mostly street driven?

Are you referring to GM and Ford SS and stock class NHRA racers?
The intake manifold inlet temps has a lot to do with how much HP each tune up will make, based on fuel used, the AFR dictate how much power the motor will make with that tune

That is a good point.

Has any racer gone full “Type 93 Torpedo” and used pure oxygen, or even liquid oxygen to out do the competition?

https://en.wikipedia.org/wiki/Type_93_torpedo

sample quote

The Type 93 torpedo had a main chamber filled with pure compressed oxygen, a joint regulator valve preventing reverse flow, and a small (approximately 13-liter) high-pressure air tank. First, compressed air was mixed with fuel, and the mixture was supplied to a heat starter. Ignition started gently, with the mixture burning steadily in the engine (if oxygen was used at this stage, explosions were common). As the compressed air was consumed and lost pressure, high-pressure oxygen was supplied from the main chamber through the joint valve into the compressed air tank. Soon the air tank was filled with pure oxygen, and combustion continued in the engine.

end quote

If as few as one tracer bullet from an attacking airplane hit a Type 93 at its pure oxygen tank, the exploding torpedo could sink the vessel, so Japanese Captains began shooting off all their torpedos at the first sign of an attacking airplane

I know the fast small tire guys go to the line about as cold as possible, but warm oil.

Cab,
You can spot these connectors on most all brands...

Point well taken and this thread, like many has wandered some.

However for the street there may be a difference in maximum power and what is good for the engine long term.