are downpipes are bad for STis?
05-19-2006, 04:10 PM
#1
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downpipes are bad for STi's!?!?!?!?
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?
"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?
05-19-2006, 06:08 PM
#2
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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.
05-19-2006, 06:45 PM
#3
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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.
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.
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