i used the turbo off my 03 when we put a 12v in the 03 truck it would spool up fast but would get higher egts faster

 

I wonder if the "acceleration" of the EGT's matter, or is it just the maximum value that matters to us.

 

Sorry, i have a 341 on my pickup now. You have to remember also that the whole system from turbo to the engine is much less restrictive on the newer trucks.

 

My bad, I realized after I replied that you had the thread on cumminsforum.

 

That's an excellent point. The heads flow better and the exhaust has wider bends up front with the low-mounted turbo. The 12v has to work harder (flow more air) to hit the same EGT points. Our '07 seems to run very similar boost and EGT points as the '91.5 across the rpm range - same size compressor wheel, full 4" exhaust on both trucks. But the 9cm housing on the new truck spools instantly, while the 12cm on the 91.5 spools quick it's not that quick, delivering about the same boost/EGT numbers across the board.

 

The fuel system has a lot to do with it, too. Much tighter control over fueling and timing.