4" or 5" exhaust

[ridesdirt]

Gathering parts for some performance upgrades. Truck currently has SCT livewire, Magnaflow exhaust w/ DPF delete, stock air cleaner. Changing to this; H&S mini-max, S&B cai, EGR delete, coolant filter, new exhaust with downpipe and CAT/DPF delete.


Question is what size downpipe and exhaust... I think 4" downpipe, but is there any advantage in performance between the 4" and 5" exhaust?


I will probably run straight pipe, and really have no future plans for more power, just reliability, so maybe headstuds & gaskets (if/when I do headstuds, will clean the intake too)

Oh yeah, looking in to the CCV deal also...

[superduty6.4]

The only difference between 4" and 5" will be the sound. 5" has a deeper sound.

[travisH3]

5". You will regret the 4" down the road like I did my 6.0. But if you don't care about looks or sound then 4" will do ya just fine

[blackcloud2k]

You already have a 4" on the truck. Only real gain going to a 5" will be the tone. I would just add a 4" DP and you will be good to go.

[ridesdirt]

Originally Posted by blackcloud2k

You already have a 4" on the truck. Only real gain going to a 5" will be the tone. I would just add a 4" DP and you will be good to go.

Current DPF pipe is 3-1/2 with the large flat flange, truck still has CAT. there is a 3-1/2 to 4 increaser right at the M'Flow muffler. That is option 1, keep the muffler back and just install 4" downpipe and 4" CAT/DPF delete pipe. Back half of the M'Flow is really nice, splits into dual tailpipes with two SS tips behind right rear wheel.


I think we will go with the 4" setup, but I have access to a new full 5" system for very very very good price, so option is there.

Thanks