My friends NA 87 Rx7 is running COLD all the time now, cause we put in a 160 degree thermostat! I was wondering if that is hurting his POWER or not. Is it better for an NA to run COLD or NORMAL for power?

 

Ya I want to know this too...bump^^

 

get a OEM thermostat if u dont want problems

 

If the engine doesn't meet it's 'operating temperature', the ECU will never switch from open loop to closed loop operation.

That will shorten your motor's life. At least, that's what the Haynes manual says.

 

Anyone know what that operating temperature is?

 

The factory manual seems to hint at 180* being a "normal" temp. That's the temp they have you test the sensor at anyway.

On alot of piston motors using a lower temp thermostat is a good way to fool the computer into dumping more fuel to make more power. The ECU sees the motor as cold and adds more fuel. With current fuel injection the system runs lean under "normal" temps to lower emissions. Don't have the manual here to say what the RX7 ECU does with a cool reading. I'm assuming it would richen the mixture as well. The main point is that is it's running rich in the first place your wasting fuel and hurting power. If it was lean it might help. Another point is that you'll get a more complete burn in a hot combustion chamber (assuming there's no pre-ignition source). Heat is good to a certain extent. Playing with the thermostat is a balancing act just like the rest of the motor.

Chris

 

Stock thermostat is 82 degrees celsius, which is about 160 degrees roughly, so you pretty much have the stock thermostat. how cold are you exactly running? on the stock temp gauge, while warmed up you should be about 1/4 to 1/3 the way up.

Stock thermostat has proven to be the best one actually, and to last the longest.

 

Uh, 82 degrees Celsius = 179.6 degrees Fahrenheit. That seems a lot closer to 180 degrees to me. At any rate, I am running a 180 degree stock Mazda 'stat in my 87 TII, and my temperature runs about 1/3 up the stock guage. I understand that from '89 on, the guage will run about 1/2 up for the same 'stat. My 2 cents, anyway

Irv, Keith's dad

 

Warmer is more efficient. Boiling over is not. Cold is not good. Reason: Hearsay since I was a little boy. Probably the parts were made to fit and function better at full operating temp. That said, I've run without a thermostat for months on end without problems(except for idle being high because the thermowax would take forever to make the idle cam come off the roller) because I was too lazy to take the fifteen minutes out of my day to put it back in. While I'm here, here is a good site to bookmark http://www.tbaytel.net/rgrau/convert.htm not rx specific, but handy. And here is another just for fun http://www.howstuffworks.com/