Engine/Transmission (1994 - 1998) 4" exhaust

[Lightfoot]

I just had a 4" exhaust and 2100 cfm. muffler installed on my '96 to help cool down the turbo when pulling in the mountains. The shop, Stan's Headers, which does nothing but performance diesel and gas exhaust systems claims that this system, with the catalytic converter intact gives a 20 hp boost, more boost without the catalytic converter (which by law they can't do). I have been told by a friend that there is no hp boost with the 4" installation, just the cooling advantage for the turbo e. g. t. . Anyone know about a hp increase with the 4" pipe? Im new on TDR and this may be old stuff but I would appreciate any input.



96 2500 4x4pacbrake353gearsAT4" highflo mufffler

 

[BTighe]

the 4" exhaust doesnt add any power worth talkin about. what it does is lower your egt's so you can add the fuel to make more power. do you have to do emissions testing. if not i would make the kitty disapear. i noticed when my exhaust was strait piped the turbo spooled slower that when i had the magnaflow installed.

 

[Smokin Ram]

the 4" will cool you down, and improve your milage, ive seen a stock 3. 5 " system straight piped add 40 hp, the 4" will give you about that too, but its not a huge upgrade. I ve got a Hotrod diesel 5" stack kit, (5 inches right after the 4" down pipe)

and ive seen a phenominal different in take off power, and mid range over my winter 4" inch dual system, it does make a difference I find.