I've been thinking about this because I'm wondering if my stock one is causing my car to run too rich... Most of the time, my temp runs really cool, less than 160. I have a Stewart high-flow pump and an aluminum radiator and a 200/185 fan switch, 195 thermostat. I don't have ANY cooling problems, just concerned about the ramifications (if any) of running the engine TOO cold. Any advice on this? Thanks...

KAM

 

Engine temp isn't gonna effect exhaust temp by too much...you only NEED a heated unit if you are running headers and getting code 13 (and maybe 44) from the O2 not getting hot, which is usually only a problem with longtubes.
...ed

 

Your engine was designed to run at 195. It is most efficient and has the least emissions at that temp. A lower temp could make more power, but really 195 is the best temp. A 180 works nice since it opens and the engine runs around 195.

If you run a stock prom and have installed a lower thermostat, then the ECM will think the engine is warming up and it will run rich. If you want to run a 165 thermostat, best to get a prom designed for that.

I run a 180 stat on a stock prom and I can tell the ECM keeps the idle up like a fast idle. Except on those hot days when the temp climbs in the 195-200 range. Then it idles like it should.

Mark.

 

I do have a 195 thermostat installed - my engine just never really gets that hot, and my gage and sending unit are accurate. As it is now, I have a pegboard in front of the radiator for these really cold days. After the car's been running for 15-20 minutes in town, it'll warm up to about 160 and more, my concern was just burning rich for the most part, since it takes so long for my car to warm up. Thanks for your responses...

KAM