What is the stock mm size for the 3.7 thermostat? . Anybody have one on their 3.7 V6 and notice any performance difference? If the 180' thermostat wont help the v6 then I wont bother with it.
The only thing a low temp thermostat will prevent is the vehicle ecu from entering closed loop operation. When first started and until normal operating temp is reached, the vehicle runs a default program which is slightly on the rich side (fuel wise). Once the vehicle reaches normal operating temps, it then takes readings from all sensors such as the mass airflow and 02, etc. and continually adjusts the fueling to get optimal burn. There are a couple of reasons not to fool with the thermostat by replacing with a lower temp:
1) You will likely get a check engine light in a short period of time since the vehicle will never reach the proper operating temperature.
2) Running the default mixture 24/7 can damage expensive emissions equipment like the CAT converter which is pretty expensive to replace.
The general idea of doing this is that it will keep you on the rich mixture and result in better performance. Unlikely to work IMO.
The only reason to replace a thermostat is to install one of the new fail-safe models which fails in the open position to prevent overheating.
Thanks for the info,I guess I can cross this off my mod list. I read a few guys here with hemis and srt8s that switched to 180' thermostats and they didn't seem to report any problems, but im not going to tempt fate.
Here is a good article on how cooling systems work.
By changing to a lower temp thermostat you are changing important variables around which the engine and other components were designed. Some will always argue that this is okay or that you can tune the ECU to accept these changes. My opinion is that this modification is not a good idea at all.
Here is a good site that explains how cooling systems work and also an excerpt about the thermostat:
'The thermostat in your vehicle is what regulates how fast the engine warms up and at what operating temperature it will run. Warming the engine up is very important due to the different expansion rates of all the internal parts (aluminum, steel, cast iron and rubber seals). If an engine is running too cold, the tolerances within are not correct and damage may ensue. Just as important is that the engine runs at the proper temperature. Today’s vehicles are designed to run anywhere between 200-220 degrees Fahrenheit, it is the thermostats job to regulate the fluid flow through the radiator to keep the temperature at a predetermined level. Most fuel injected vehicles use a 195-degree thermostat, so by 200 degrees it is fully open and letting the fluid flow through the radiator and back to the engine.'
I have to say that my 4.7L runs LOADS better after i put a 180* in it. I have a superchips programmer and running a tune i noticed it would run a little hotter. The 180* made the engine sound alot smoother.
If it runs hotter with a tune, it is frankly a bad tune, as it's running too lean. I have a custom tuner with custom 87, 89 and 93 octane tunes, and all run at the same temps, all year round.
These baby 3.7s dont make enough power/heat to even need to think about it. The gains would be minimal for these motors anyway. The fact they don't make one says it all I think, def leave it alone, my .02