Engine/Transmission (1998.5 - 2002) Egt

[JimKing]

I have 1200 miles on my new pistons, replaced because of a bad genuine 275 injector. My prior setup had the EGT thermocouple in the exhaust about 3" from the flange. Temps then rarely saw 900. New setup is thermocouple in the turbo mounting flange.



Just back from a test run prior to going on vacation. I pulled my 5er (10,000 lbs)17 miles up a 6-6. 5 percent grade starting at about 4000 ft. and going up to 6500 ft. Traffic was a little heavy but I was able to let it drag down to 35 then went WOT the last 2 miles.



At the top (6. 5%), speed was 61 mph, high gear, no lockup, engine turning about 2650, turbo 28. 5 psi, EGT was only 1140



So my question is. Am I just real lucky or could I have screwed up the putting it in. It looks good, doesn't touch the manifold, is positioned exactly as the directions posted at Genos.



Oh yeah, the new pistons are ceramic coated. That is the only real change. .

 

[Chipstien]

Most of us are running the thermocouple in the exhaust manifold BEFORE the turbo. That is why your reading seem low compared to us. 1140 post-turbo seems high for extended periods. I believe those running post-turbo should be adding 300 degrees if memory serves me correctly. Maybe someone will correct me on that.

 

[Beast2B]

Chipstein, I think the last sentence in the first paragraph means he moved the thermocouple to the turbo mounting flange, should be pre-turbo.

Jim, What benefits should you see from the ceramic coating? Slower heat saturation? Lower crown temps?

 

[JimKing]

I am not sure. The pistons were ordered by my mechanic who seemed to think I needed them. The thermocouple is pre-turbo. I think the temps are lower than I had anticipated.

 

[cumminspwr01]

Unfortunatly the whole adding 300* thing doesnt quite work. I have a sensor pre and post turbo and they are hardly ever within 300* of each other especially at wot. At idle they are almost identical but as soon as you start to supply the fuel they are in two different worlds. When my post turbo gauge reads 900* my pre turbo gauge is usually well on to 1350*. My first gauge was post turbo. I'm real happy that I now have one pre turbo.

 

[Hohn]

Jim, it's possible that you're seeing the benefits of the ceramic coating.



The thermal barrier coatings decreased heat loss to the piston crowns. Thus, more heat in the chamber and more complete combustion. Better combustion= lower EGT. At least, that's my theory



Justin