After market exhaust?

[BurnsK]

I previously owned a '99 F350 Power Stroke and when I installed a 4" exhaust, it raised the RPM torque curve. It took 100 - 200 more RPM to get the equivelant torque. My current truck is a DA LB7 with no mods. Has anyone experienced this torque shift with a larger exhaust? I would like to install the bigger exhaust, but not with the consequences I had with the PS.

[Kennedy]

I have my exhaust dyno plots listed on my web site for the LB7 and LLY Duramax.

http://www.kennedydiesel.com/photogal/pages/4-5exhaust.htm

http://www.kennedydiesel.com/photogal/pages/4-5exhaust_lly.htm


While the plots are 4-5" the results should be similar...

[BurnsK]

Thanks for the data. It appears as though the exhaust upgrade works better overall. With my old 7.3 PS, you had to rev it more to get the additional power, like an old "Jimmy" two stroke. Appreciate your efforts.

[Tsckey]

John,

Are those plots with a full turbo back system, or cat back? If the former, do you have any plots for a cat back system?

TC

[Kennedy]

Those were full syetem, no cat. The LB7 had no cat to begin with.

I've never really monkeyed with cat back systems.