Just recently put a 4" turbo back exhaust on my 01 Duramax and it feels as though i've lost some power throughout the rpm range with it. Seemed like with the factory exhaust, the truck pulled harder and and accelerated quicker. Has anyone else experienced this? I don't have a boost gauge yet so I don't know what my before and after boost numbers were either. Will the larger exhaust decrease my max boost and how fast it comes on and if so, could this explain what i'm feeling? Also running a Predator on the 85hp setting before and after the new exhaust and a swiss cheesed air box. New to turbos so hope I don't sound lost. Any help and input would be appreciated. Thanks.


Ken

same exact feeling i got when i put my magna flow 4inch on with an intake and a 95 hp bully dog,..dont know why either?

Anybody?

Maybe you've lost off boost power...??


I know in my WRX when I put a 3" catless DP on there, I lost power until the turbo came alive then gains were large from there on up.


Just throwing out ideas. http://www.dieselplace.com/forum/smileys/Approve.gif

Going to my 4" straight pipe I didn't really notice power loss as per say, but I didn't notice gains either until turbo spools up, just like Hit Man X said.


-Zorganov

roguedriver,


A lot of customers "feel" this also so your not alone. But it's an illusion in most every case, the sound and the differences in the truck present the impression that you lost bottom end etc. But if you dyno it before and after it is the same or better by placing the rpm curves on top of each other. A lot of Ford guys have this thought as well.


Mark @ DPPI

I understand what your saying Mark. Wish I would have had a chance to dyno it before and after. Is there a little more of an acceleration lag initally when you put on the larger exhaust on the turbos? I know as the rpm's climb, you will be better off with the larger exhaust, but was just wondering since the diesels make the biggest power on the low side. Maybe i'm just spoiled from my NOS fed Z28. 500ft/lbs in an instant at the flick of a switch. Hehe. Thanks for the input.


Ken

I put the AFE stage II air intake and Banks monster 4" exhaust on the same day, so I can not help. However, I noticed a huge difference in turbo spool up and it seems like the truck had a lot more power. Some have noticed up to 6/10 of a second better time in 0-60 runs. I would think that is about what I would see.