So as you know they make a higher temp spark plug and a lower temp. basically the center is electrod is either less exposed or more exposed..

With a 180 stat in the truck what is the proper plug that should be running for best performance and MPG with running cooler temp?

 

Correct me if I'm wrong but a 180* stat cools the engine to give you a denser air/fuel mixture. Since you have a denser mix you would want a higher temp plug to combust more of the fuel, thus giving more performance and higher effeciency.

 

for each 70hp gain over stock go one range cooler spark plugs. if you run a 180 just use the same oem plug. the 180 just starts cycling coolant earlier unless you have a better efan or programed to come on earlier then it dosent really keep the engine cooler. just a head start on cooling.

 

Dodge uses a 195 degree thermostat at the factory. A 180 degree tstat will trick the PCM into thinking the engine is not reaching full operating temperature. So in response the PCM will richen the fuel mixture a bit and advance the timing just a little. You get a little more power out of it but you can also lose MPG from a 180 tstat too. I put a 180 tstat on my truck and did not really see much decrease in MPG. Dodge engineers did a study some years ago and found the Magnum engines actually make more power and are more effecient at 182 degrees, but they had to use a 195 tstat to meet the Federal emissions requirements.

When you add a 180 tstat and go one range colder on the spark plug the combination of the plugs and tstat can help eliminate preignition ping. It pretty much makes it impossible for the engine to ping. That was why I added my 180 tstat. My engine had pretty bad ping, and I had already put in a set of Autolite 3923's and a few other types of plugs too trying to fix it but I still had bad ping under a light throttle. About 4 or 5 years ago I added a 180 degree tstat and the ping has been gone ever since. The 180 degree tstat and plugs helped my power by a small amount too I guess. It was never a phenomenal difference, but it helped a little.

I used 3923's since the time when I added the 180 tstat, and up until my last tune-up. Not long ago I read that Autolites are made in China now and I read some online horror stories about the Chinese-made plugs. So I did some research and decided to use NGK plugs. I did my tune up with new wires, cap, rotor and a set of regular copper core NGK FR6F's in the stock heat range for my truck. That was back in March and the ping is still gone. I have a theory that because I have been using a fuel additive in every tank of gas for about the last 2 years, it cleaned the carbon off my pistons and that is why the ping is gone even on a stock heat range plug. I don't think a 180 tstat by itself can get rid of ping but I could find no posts to prove it. I posted here about it and no one else had much info on it either, so I tried my own experiment and so far my truck is doing fine. Dodge engineers also did another study and found that the Magnum engines do best and make the most power with a plain old copper core plug. I like how my truck runs the way it is set up now. As long as the ping doesn't come back I will keep using the NGK's and leave the 180 tstat in place too.

Just my 2 cents on it.

Jimmy

 

My bad. So colder is better when reducing engine temp. Got it.