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clconversion
01-10-2005, 07:44 AM
When I install my K04 upgrade I am going to take my car to this custom exhuast shop around where I live very respectable shop now Which size is going to be the best to get to go with the K04 i was thinking 3" downpipe with either 2.5 or 2.75 all the way back

IndieRockSteve
01-10-2005, 08:33 AM
6" but don't tell anyone...

search, this topic has been beaten to death, resurected, beaten to death, resurected, tortured, labotomized, electroshocked, let lie in a vat of its own vomit to die, resurec.....

mike-2ptzero
01-10-2005, 11:19 AM
Originally posted by clconversion
When I install my K04 upgrade I am going to take my car to this custom exhuast shop around where I live very respectable shop now Which size is going to be the best to get to go with the K04 i was thinking 3" downpipe with either 2.5 or 2.75 all the way back

With the K04 setup 2.25-2.5" is enough.

nizmosx
01-10-2005, 11:23 AM
i would do 2.75 downpipe to 2.5 piping, no need to go three on just k04
do a search tho indie rock was right about the beatings,

JMG
01-10-2005, 11:23 AM
Going from a 3 to a 2.5 might be too much of a restriction. Going 3 all the way back would allow the exaust gases to cool too much (cooler=denser=harder to move=restriction for a KO4 setup). So I'd go with 2.5 all the way, downpile and all.

Daft
01-10-2005, 12:06 PM
JMG is correct. Exhaust diameter is crucial for velocity. You never want piping diameters to step in large intervals along the car.

If your turbine has a 2.5" outlet on it, use a 2.5" DP. Once you get to the cat you can step up in size but, you shouldn't put a 3" DP on a 2-2.5" tubine outlet to just end up going back down to 2-2.5" diameter. That will kill the velocity of the gasses as they are traveling out the pipe.

A turbo charger would be quite happy with no exhaust whatsoever but, you need it so, either make it uniform all the way or have it grown in size from front to rear. Never drop back down in size.