Performance Exhaust Systems

[MountainMan]

I have been probing around looking at different exhaust systems for a 2006 6.0. A couple questions come to mind.

1. Generally speaking will a 5" diameter exhaust deliver more HP and/or torque than a 4" diameter exhaust?

2. Is there such a thing as a too big diameter?

3. How is torque and HP affected by exhaust pipe diameters?

4. Does exhaust scavaging come into play with a turbo diesel, or is this concept old school with respect to naturally aspirated gas engines?

5. Does removing the CAT affect performance that much?

6. My main goal is towing, is a 5" better than a 4" for this purpose?



Sorry for all the questions.

[Raul@Stealth Automotive]

their is no bennefit to going 5" over 4" other than sound... if it were my truck i would just stick with a 4" straight pipe exhaust.... your not going to get that much more HP out of a full exhaust kit.. the main benefit is lower egt's... and i would def remove the cat for better flow...

hope that helps

-Raul

[beemerbiker5]

Originally Posted by Raul@Stealth Automotive

their is no bennefit to going 5" over 4" other than sound... if it were my truck i would just stick with a 4" straight pipe exhaust.... your not going to get that much more HP out of a full exhaust kit.. the main benefit is lower egt's... and i would def remove the cat for better flow...

hope that helps

-Raul

I know this is an old post, sorry. I am a newbie here and to Powerstrokes. I get that there is no advantage of 4"v5", but would you go Turbo-back or cat-back? If cat-back, would you remove the cat in the process? Thanks for any info.
I have an 06 Ext Cab, short bed, Auto, 104000 miles.

[njmudrat]

Cat-back leaves your cat in place.I am in the same boat as you.I am tending towards a 5" cat back and can always add a cat delete when I want a straight pipe....I am looking for noise only and not really interested in performance gains.I don't have a tuner and not looking to add one in the near future....

[85pickup4x4]

i have looked and looked and looked for a exhaust manifold for this truck. i want to open the exhaust flow up to the turbo. do they even make performance manifolds for these trucks cause i have not seem to find it. anyone know where i can find one?

[85pickup4x4]

any word on the exhaust manifold???

[Evil Eye]

What would be the advantage to flowing more exhaust to the turbo? That would be a function of the y-pipe and I haven't heard of anyone modifying the y-pipe to improve flow with all other elements remaining stock.