im running a built b20v (all motor) and im wondering if a full 3in exhaust from header to vibrant would be too big.

im around 21Xhp as of now and hope for more after i get better cams/springs/retainers.

i HAVE searched and i've read many threads with the same question and some people say 2.25in, most say 2.5in, but some people say 3in will work good too.

whats the verdict?

 

it's not. if you can deal with the extra noise it's the way to go.

 

how much extra noise? its not too loud right now with 2.5in with a vibrant.

im using a plm big tube with a 2.5in collector

 

depends on what muffler and resonator you use

i run a full 3" catless with vibrant ultra quiet resonator and oval muffler and cruising around town it's not very loud at all. highway cruising isnt bad either and there's not a lot of drone or raspiness.

it's only annoyingly loud on cold starts and WOT.

 

i'll be using a vibrant resonator and streetpower with full stainless 3in mandrel bent piping

should be reasonably quiet?

 

Better engine breath = Hp GAIN

 

it should breath pretty damn good.

ported gsr head with ctr cams/springs/retainers
skunk2 mani with 70mm tb
pwjdm power chamber intake
plm big tube tri y

 

IMO, one should only use 3inch exhaust if you're boosted or heavily built (in your case)