Can someone please explain to me how you gain 4-5 PSI when you install a 3" turbo back exhaust. I was telling a friend about it and he said "You mean 4-5psi of creep right?"

I always thought it wasn't creep? maybe I'm wrong. Will someone please explain how this happens, because I would like to give him a good answer.

Thanks for any help.

 

its creep

 

creep

the wastegate maxes out and it can't bypass enough exhuast around the turbo so more goes through it.

 

A 3" exhaust will have less back pressure so boost will rise. It is only boost creep if your wastegate isnt ported or if you cannot control it.