Quote Originally Posted by arveetek View Post
Jim,

When my '81 was naturally aspirated w/stock CR, I saw EGT's up near 1300 and spikes up to 1400. Towing my 5th wheel (like I did to Dayton in '01), I regularly saw 1100 to 1200 for hours on end. It never seemed to bother the engine.

Installing the turbo and 4" exhaust with no other mods reduced the EGT's to a max. of 1050 at 14 psi.

When I rebuilt the 6.2L a few years ago, there was really very little cylinder scoring, just some slight piston damage. It was running just fine at the time. I only pulled it to replace lifters and a few other things, and then those "might as wells" started kicking in...

I don't think high EGT's are nearly as critical on a n/a engine as they are on a turbo'ed.

Casey
Casey,

Your experience does illustrate how a turbocharger reduces EGT under similar load conditions. EGT is a reflection of combustion temperatures (a ratio of), where combustion temps could be 3000+ at max load, but it cools to 1100-1200 when measured in the exhaust manifold (due to expansion and absorption). This also dispels the notion that the NA precups will suffer excessive damage when turbocharged. The EGT limit remains the same for either a turbo or NA 6.2/6.5 engine.

Back in the MFI days, diesel engine manfacturers rated their engines at a specific EGT (usually 1100 degrees F) and sometimes also exhaust opacity. This isn't true so much anymore with electronic fuel injection systems.

Jim