Originally Posted by evokenny

wow thats really nice to know [= no need for a aftermarket dp then , more money for other mods

Originally Posted by flyboytb

downpipe / o2 housing combo does show gains... this is the setup most vendors offer.

Originally Posted by DaveGSR

we're all looking for dyno proof of this...

Originally Posted by UT_EvoX

That makes no sense since the O2 housing and downpipe are post-turbo restrictions. Making them higher-flowing would allow the same turbo on the same engine to produce more boost efficiently since the turbine wheel would be under less back-pressure on the exit side.

Same goes for replacing your exhaust with a high-flowing cat-back exhaust. It will decrease spool time and cause your boost to actually increase.

Eliminating intake restrictions and increasing internal engine efficiency would cause the effect you describe.

Trust me, I've been through countless iterations of exhaust systems on my other turbo car. Less post-turbo exhaust restriction = more boost. You're right about the required WGDC, however. But it's intake restriction that regulates boost pressure, not exhaust restriction.

Originally Posted by mlomker

You guys resurrected an ancient thread where AMS showed no results with just the downpipe. I assume this was before they created and began selling their own o2/downpipe. It's the o2 part that gets you the gains.

http://www.amsperformance.com/cart/A...-Downpipe.html

There are all kinds of dyno graphs showing the gains from o2/downpipes. This is the brand that I bought:

Originally Posted by evoxdreamz

Does the stock downpipe not have a cat on it? also jsut to be sure adding the 3 inch downpipe one like turbo xs without the o2 elbow adds no power?

Originally Posted by Gyroscope

A lot of people are saying downpipe but they just mean the downpipe not the elbow. If you mean the elbow and the downpipe then say so. They are 2 different things even though some campanies make them the same thing...

Originally Posted by JLEVOX

Great info!!