I've been tunning up my engine and I've gained about a half second in 0-60 MPH so far. I'm currently running a 160 Deg. thermostat and conservative base ignition timing. I've read that greater heat in the cylinders equates to greater horsepower but I also know that higher cylinder temps limit how much ignition advance you can run before detonation.

Right now the engine runs very cool especially on the highway. My question is should I put in a hotter thermostat (180) and max out my initaial timing or should I leave in the 160 therm. and max out the initial timing knowing that it might allow for a few extra degrees of timing.

Which should produce more power - higher cylinder temps or a few more degrees of timing?

 

Well...hmmm, gotta think about that one.

Well, 'bout 80% of the energy released from the fuel burn is excess heat. Also known as 'wasted energy'. I don't think keeping everything warmer will make more power. It might improve exhaust velocity by keeping (slightly) more heat in the exhaust gas, but that's about it.

I believe a couple degrees of timing would be worth more.

Anyone else want to spread there knowledge???

 

In an engine that has warmed up to a normal operating temperature, a 160 deg. -vs- a 180 deg. thermostat will make little to no difference in the engine running temperature, or the cylinder tempertures for that matter.

The lower temp thermostat just opens/closes at a lower temperature. The gist of it is that your heater just takes a little longer to put out good heat after a start up....

 

cylinder temps and water temps are two very different beasts when it comes to making horsepower.
As far as engine "coolant" temp it's good to keep it low if you can if for nothing else, the motor will run more free because of parts growth internally and oil failure with excess heat. The 160 stat is great as long as it doesn't cause it to run hotter(sometimes a 160 stat will cause a hot problem as well)
Now cylinder temps are where heat and cooling have the most affect. A cool charge of air/fuel mix is more oxygen dense and allows for more fuel molecules per cubic inch/foot) than a hotter one and that's where you make horsepower....getting more fuel/air mix into the cylinder as efficiently as you possibly can(which is why forced induction works) The more full the cylinder, the more bang you get when it lights off which is how horsepower is produced. Getting the mix in and the spent mix out is where all your power is made and the reason why cylinder heads and a good camshaft combo is the most important thing you can have. The rest is purely physics. I wish I could explain this more simply but it's just not that easy.
Personally I'd leave the 160 stat, bump the timing until it rattles a bit and then back it down until it goes away(or about 38 degrees of total if you can get that out of it) Remember that detonation starts well before you actually hear it....by then it's too late!!

 

As far as track times, the colder my car was, the faster it ran.

 

 

Could the colder your car was and the faster track times be attributed to both of you having fuel injection? When running at WOT wont TPI go back to open loop anyway which is when a car is cold it will be in open loop as well?

 

Computer control does not affect this. The same applies to carbed engines as well. The power extracted from fuel is optimal in certain temperature range. Once the temperatures increase too much, the power extraction is not as effective.

Our cars run between 200F and 220F stock. These higher temps help reduce emissions but that's already too hot to get the most energy out of the fuel. Boats, for example, are not subject to emission testing at all here so they use 160F thermostats, to lower the engine temps and maximize power. The only drawback is higher emissions but everybody knows that this government doesn't give a flying squirrel.

Hope this helps a bit.
Lou

 

Does anyone know, does the ecm look at the O2 sensor at WOT?

 

Shouldn't.
WOT should run in open loop.

Lou

 

Ahh, thats what I thought. Thanks.

 

Engines like cold air (hence a cold air intake) Heat is what make a car lack performance. That's why people try to limit the amount of heat the best they can under their hoods.

 

I've read that increased cylinder temp = increased cylinder pressures = increased HP.

 

Only up to certain point.