Just bought a Duramax

Vintage465 wrote:
So I got a ton of great info here but I need to state my reasons for asking these questions. I am not "looking for power". I think pulling a 24" trailer @ 5200 pounds this dude shouldn't need more power. What I was thinking is making the engine more efficient and better. I was thinking, if a Banks Ram Air system could lower EGT by forcing more enriched oxygen into the intake then that would be something I could justify. If the better intake provided better mileage that would be cool too. I know I would not really get a payback on my investment in any short amount of time, but one must remember, I keep my vehicles for a minimum of 15 years. Regarding the exhaust, the only thing I am looking for with that is to get rid of the gigantic and exceeding ugly exhaust tailpipe. I can't really believe someone at GM got done with that tailpipe and said, "there...that's workable and nice looking too"! So my reasoning is better flow for cooler exhaust temps and more efficiency if that comes along with it.....and gosh the ugly exhaust pipe!

thanks,

You're not going to find a "Cooler" exhaust pipe than OEM. Many of the aftermarket have their pipes with venturi vents cut in them, but none of them mix as much fresh air with the exhaust to drop the tailpipe temps as much as the OEMs (This applies to Ford and GM products, RAM doesn't have venturis in their exhaust). But yes, I have to agree that GM products of the 2007 to 2014 exhaust are pretty ugly. They've done a nice job with the current trucks of cleaning up that exhaust system's looks.

As for the tuning, if you put in more oxygen into the engine, you're going to get more NOx out of it. This is assuming you don't plan on removing emissions. So any aftermarket tune that reduces EGR mixing and puts more fresh air into the air charge will cause the emissions to use more DEF to tamp down NOx emissions. Just another thing to think about. Also, aftermarket tunes seem to put out more soot due to more fuel enrichment to increase power levels. So that tends to lead to more regeneration events and counter-intuitively more fuel being burned due to regeneration.

In fact (again, assuming you're keeping all the emissions), you will want to keep the higher EGT's coming out of your engine as you want to have as many "Passive" regeneration events as possible. This greatly reduces fuel usage. My RAM will average about 23 to 25 mpg on a cruise to the coast and back (250 miles round trip and hand-calculation verified). What really ups the fuel usage on OEM tuned vehicles are stop and go drive cycles, where you don't keep the exhaust hot. Then soot keeps building up and the system eventually needs to burn all that soot out there somehow (hence "Active regeneration").

Hope this helps.