i didn't get any answer in the exhaust forum but here is my question:

i have a F250 SD 6.0L diesel i don't do any towing that much just some wood hauling every now and again, i don't run a tuner (yet ) is it OK to run a 5" exhaust?

 

You can run a 5" with no problem. It will lower exhaust gas temps, that will make the engine last longer.

You'll also have the benefit of a good sounding truck.

 

yep, hes right no back pressure is required for a diesel

 

One thing to keep in mind is the size of the exhuast can make your torque band change a bit. When I had my 7.3, the change from a 3.5" DP, with 4" back to a full 4" system made a noticeable change to my low end torque. I'm not sure if that's the same on these 6.0's or not, but I've also hear that the 6.0's run a little better with some back pressure. Your mileage may very.

 

Spot on Basstardo. I've seen some mfg of exhaust systems recommend sticking with a 3.5 inch DP vice a 4 inch DP if a tuner is not going to be used for this reason.

 

Just to put my .02 in. You should stick with a 4" exhaust. A 5" will actually hurt performance a little, and is not necessary unless you have well over 500hp.

Also the way most people do it is get an onroad exhaust (cat and muffler) then just put straight pipes in place of the cat and/or muffler so they can bolt them back up for emissions testing. You will see the highest drop in exhaust temp with the muffler and cat removed.

 

Thx guys i guess ill do the, 4" i was just curious cause i found a 5" aluminized with cat delete for the same price as a 4" stainless steel with cat delete