I got 95 psd and I was talking with one off my friends who is a mechanic and he told me that it will be bad idea to due straight pipes with my truck and if I due it I will mess up my turbo.he told me I need back pressure because with out the back pressure the turbo will spin freely and faster in high rpms and when you let go the gas the oil presure will drop not giving the turbo enough oil and turbo will be still spinning fast or some crap like that .is that truth ???

 

Nope. Straight pipe is fine for these trucks. The Turbo itself creates all the backpressure your engine needs.

 

James is right! Plus, straight pipes help keep the exhaust temps down when haulin!

 

X3 Straight piping it won't hurt anything, only help.

 

Hope he's not a diesel mechanic.

 

4" straight would be perfect, 5" will slightly hurt power if under 500hp but not noticable and IMO it sounds better

 

Why would a bigger exhaust hurt power? Just curious.

 

Something about exhaust speed. 5" exhaust slows down the gasses creating more backpressure unless you are pushing a LOT of air

 

Your friend is wrong. These aren't gassers with complicated emissions control systems. Straight pipe and motor on.

 

Would the truck still pass inspection with straight pipes no cats?????

 

Depends on what state you are in. Here in NC they don't care that my cat is gone because they don't do an emmissions test on older diesels like ours, but you have to have a muffler. So I found a Cherry Bomb glasspack that's 4" diameter and only 8" long. Still basically straight-piped but it's a "muffler".