I got this from JSC Speed:

"04-06 STi OWNERS READ: On the 04-06 STi there are boost spike or creep issues in all cases with the use of an aftermarket downpipe or turboback that uses a bellmouth or external dump tube design. This is because the 2.5L engine pushes so much air. Even with the internal wastegate fully open not enough air can exit to stop spinning the turbo, the result is boost creep or boost spike. You can fix the problem by porting the stock turbo's wastegate passage (any exhaust shop should be able to do this or it can be done at home) or you can get an engine management system to fix the issue, like a UTEC or AccessPORT."

true?

 

They are not bad. You just cannot bolt the downpipe on and expect it to be handy dandy. Most STi owners get their turbos ported at the same time. So yeah, its true.

 

At at a certain extent yes, it can do damage when not taken care of.

From what I've been reading, a downpipe with a high-flow CAT seem to reduce the chance of having boost creep or boost spike. But definitely, if you're going that direction, it's always a good idea to match it with an EM to complete the power package it provides and for the money you're spending, it's a very good gains, especially for the 2.5L engine.

 

port the wastegate and hope it doesnt get boost creep or em would be the solution.

 

It also depends on your exhaust system.

 

Get a Cobb Downpipe (catted).

 

Get catted

 

I have an invidia non cat bellmouth DP with no EM and get no boost creep...

 

I have an Invidia divorced downpipe (no cats) bolted to my Greddy evo2 and have had no problems but will be getting an accessport for more performance

 

thanks guys and one more thing does anyone know about the new bosal downpipe??

 

just a engine mangement and rasie the boost cut psi.