Turbo Exhaust Housing Help

[Jonny P Star]

i would like to know if there is any advantage of getting a different sized exhaust out on the turbo exhaust housing. i mean not the a/r or flange size but the actual size of where the exhaust bolts on. i have a 4inch exhaust and wondering is there any advantage of getting a 3inch gt 4bolt out over the standard 2.5inch 4bolt out or any other housing options. cheers jonno

[Jonny P Star]

i would like to know if there is any advantage of getting a different sized exhaust out on the turbo exhaust housing. i mean not the a/r or flange size but the actual size of where the exhaust bolts on. i have a 4inch exhaust and wondering is there any advantage of getting a 3inch gt 4bolt out over the standard 2.5inch 4bolt out or any other housing options. cheers jonno

anyone???? just keen on knowing if there are any performance advantages to the different style ehaust housings. i have to get a dump pipe made anyway so i can get any out, just keen on knowing if one is better than the other. they cant be for just different applications and have the same flow can they, if so i will buy the cheapest one if there is no advantage. cheers, jonno

[StealthX]

Yeh I reckon there would be...

Anything post turbine, that's restrictive or small is gonna limit your power.

Turbo exhausts work on the principal that everything moves from areas of high pressure, to areas of low pressure. So consider the engine side of the turbo, the turbine wheel and the exhaust housing is a very restrictive unit, hence you'll get high back pressure on that side - which is needed to spool up the turbo well, but then on the exhaust side of the turbo, there's almost no restriction at all - just straight hollow pipes, so by making the exhaust side less restrictive, you're promoting flow through the turbo. And more air out = more air in = more fuel in = more power...

Happy boosting!

[Jonny P Star]

Yeh I reckon there would be...

Anything post turbine, that's restrictive or small is gonna limit your power.

Turbo exhausts work on the principal that everything moves from areas of high pressure, to areas of low pressure. So consider the engine side of the turbo, the turbine wheel and the exhaust housing is a very restrictive unit, hence you'll get high back pressure on that side - which is needed to spool up the turbo well, but then on the exhaust side of the turbo, there's almost no restriction at all - just straight hollow pipes, so by making the exhaust side less restrictive, you're promoting flow through the turbo. And more air out = more air in = more fuel in = more power...

Happy boosting!

so looks like i'll be going with the 3' out. now the 3" gt 4-bolt out is $110 more than the v-band 3" out. what i am asking is should i go v-band cauz its cheaper i have to get a dump pipe made any way, is v-band any good???

[StealthX]

V-band is good but i've heard they seize up after a while.

its really up to you, Vband is much tidier and easier, but 4-bolt is simplier and more reliable.