What is the correct thermostat to use on my 95 lt1 with vortech supercharger. When I did the heater core and had the coolant drained I was going change the old thermostat, to my surprise there was none. I went to napa and they said a 195 was stock so I put it in. Car runs fine but now I'm hearing I should have put a 160 or 180 in it. I haven't had it out in real hot weather yet so before I get it done should I put in a 160,180,185,190. I'm confused because the fans don't come on until 190 anyways. I was taught a hotter temp means more efficiency and cooler temps cause sensor problems and computer errors. I bought the car and always had no heat in the cold season and now I know why. What would the performance guys suggest. It has a new radiator, reprogrammed computer,afr aluminum heads,edelbrock intake and unknown different injectors, BBK throttle body, mild blower cam, forged blower pistons 9.5 to 1 headers, custom exhaust w/ cats, msd ign and distributor, coil, boost control.Just too many opinions and want to do this one last time.

 

You want a combustion engine to rapidly warm up (You must use a thermostat for coolant, and sometimes oil as well)
Modern engines should rapidly be warmed to 195*F to 205*F or even 212 to 215*F. The newer the engine the higher the baseline coolant temp tends to be. Some run even hotter.

Higher oil/coolant temperatures improve economy, efficiency, and reduce wear and tear. They are needed. Never run an vehicle engine colder than roughly 180*F to 185*F if you care about it. Although the water temperature isn't the critical factor- it is the oil temp that is most important. The oil temps need to reach 200*F~ near the boiling point of water for engine longevity and reduced wear. The reason water temp is a factor is because of the thermal expansion of parts, you need water temp to closely match oil temp. Thus coolant temps rising quickly to 190*F facilitates oil temps rapidly rising to near 190*F+ is the goal.

In some boat applications they wish to use cold water near 140 to 150*F with hot oil 200-220*F, because cold engine coolant helps increase power output.
In those cases the engines are built using a wider piston-wall clearance to make up for the low coolant temperature with hot engine oil.
This example should help illustrate how important warming the engine coolant temp to match oil temps is.
The oil temp of 200-220*F is needed to reduce the viscosity of oil and chase out water molecules from the crankcase. Combustion is composed mainly of WATER and CO2 so there is a constant steady stream of hot high velocity, high energy water molecules entering the crankcase while the engine is running which must be removed rapidly by high oil temps near boiling point of water, and removal is done using PCV system, make sure your PCV system is fully intact, OEM quality, and provides a pressure below atmospheric inside the crankcase at all times. I recommend measure your crankcase pressure to ensure this is happening.

Alright one last thing. In forced induction applications the engine may experience a rapid rising of coolant temp during extended load. This is part of forced induction tuning applications. If the goal is to run say 1/4 mile, then the coolant temp difference at the end of the race may not be very much. However if running 1-mile or some kind of extended racing highway roll racing, the coolant temp may rapidly rise beyond acceptable limits. Thus a lower starting point of coolant temp may be warranted. For example say you have a 160*F thermostat and intent to run a 1-mile race with 1000hp or something like that. When initially warming up the vehicle you would want to leave the fans off so the coolant can pass 160*F rapidly to 200*F coolant and help the oil reach 200-212*F. Then, once you get to the track, run the fans to bring the coolant temp back down near 165-170*F for the start of the race while oil temps are around 195-200*F is fine. You can have a 30 to 35*F spread between oil and coolant, should be okay. Then the race begins and coolant rapidly rises from 170 to 200 or 210*F, oil temps rise from 200 to 220*F, you wind up very "safe" with both oil and coolant temps near 220*F. That is why this aspect is considered tuning, you are tuning the start and end coolant temps to match the desired racing situation. What you don't want is to start a long race with 220*F coolant and wind up with 240+ temps at the end, or higher. Tuning must be done to avoid excessive high coolant temps at the big end of the track/racing to avoid engine damage especially when using forced induction. On the highway however 220*F will aid economy and efficiency and engine longevity.

 

Very good explanation and that's what I was taught but I'm old school, 62 and thought maybe with more advanced engines something might have changed. I mean theories usually stick. My oil is where it should be, so I'm going to try running with the 195 temp thermostat. My dad always said you can't make power without heat but you have to put a limit on the heat, otherwise all you make is the rebuilder a lot of money.

 

Yes! all power plants no matter whether steam turbine or combustion engine are more efficient when higher temperature.
Intercoolers remove heat and kinetic energy from air, thus intercoolers actually reduce power output of an engine.

It seems strange but it is thermodynamics at work. Conservation of energy.

Auto manufacturers go through great lengths to heavily insulate the engine and exhaust, contain the heat energy, improves efficiency and economy.