3inch downpipe too big?

[90blackdsmturbo]

just wondering people say its too big for 3inch downpipe if your not making enough power and rather go with a 2.5 inch downpipe. Which is better for my setup 2.5, or 3inch?

My mods are intake,hacked mas,ported o2,3inch catback,empty cat, balanceshafts removed,small ported 16g turbo with exhaust clipped 15 degrees,MBC@16psi, walbro 255, fpr,arp headbolts,advanced timing @7degrees

 

[25psi]

Nope, the less backpressure after the turbo the better. With your mods you would probably be ok with a 2.5 but why limit yourself and possibly make yourself buy another downpipe if you outflow the 2.5.

 

[hillbillyboostn]

can never have to big of exhaust

 

[tstkl]

if your exaust is too big than the air starts getting really cold before it leaves the piping and becomes really dense,...and dense air is heavier, so it requires more force (OR PRESSURE) to move it, which is basically creating back pressure on the turbo, SO YOU CAN have too big an exaust system, unless your exaust system is so short it wouldnt make a difference, which it isnt so a larger diameter isnt always best..

having said that

think about the future, if you plan on doing more upgrades, you should probably get the 3" so that you dont have to buy 2 downpipes...

 

[Coup D E'Tat]

People need to re-think the "bigger is always better" mentality. On a turbo the size of a 16g, mid-range is nice because the top-end isn't a "lot." Smaller exhausts can help with mid-range power.

People have reported trapping 4 MPH less after dropping the rest of the exhaust and running just 2.5" open downpipe (instead of a 2.5" downpipe to 3" cat-back.)

Just some food for thought.