Exhaust Bottleneck

[Neejay]

I bought a Buddy Club Spec 2, but in all the years of hearing opinions on them, I've never read or heard that it had a 2.5" resonated section.

At the flange, it's 3" then goes to a 2.5" resonated section then back to 3" piping, to a 4" outlet

RB25: 10psi, 3" turbo outlet -> 3" downpipe -> 3" test pipe -> 2.5" resonated section -> 3" piping -> 4" outlet

Realistically, how restrictive is this 2.5" bottleneck? Am I splitting hairs?

[240z4u]

At this point, its not hurting you.

[Neejay]

At this point, its not hurting you.

Cool. At what point would it start hindering me?

[240z4u]

To be totally honest, I am not sure. If/when you upgrade to a larger turbo maybe just weld in a 3" resonator. Keep in mind, it won't likely do as good of a job at toning down the exhaust though.

[Neejay]

To be totally honest, I am not sure. If/when you upgrade to a larger turbo maybe just weld in a 3" resonator. Keep in mind, it won't likely do as good of a job at toning down the exhaust though.

Ah, ok. Thanks.

Someone explained to be like this: http://www.youtube.com/watch?v=oUd4WxjoHKY

It's a venturi effect-the same principle of the carburetor and Nissan's SCV system. It's resistance that increases velocity also. You have to imagine air flow as if it were water. Imagine putting your thumb over a garden hose outlet, decreasing the diameter of pipe but still allowing flow.

[Genpac]

Is the RB25 turbo outlet really 3"? I know the RB20 is only 2.5" to the DP.

[Neejay]

Is the RB25 turbo outlet really 3"? I know the RB20 is only 2.5" to the DP.

Mine is. I have a syko turbo elbow.

[julio]

To be totally honest, I am not sure. If/when you upgrade to a larger turbo maybe just weld in a 3" resonator. Keep in mind, it won't likely do as good of a job at toning down the exhaust though.

Ah, ok. Thanks.

Someone explained to be like this: http://www.youtube.com/watch?v=oUd4WxjoHKY

It's a venturi effect-the same principle of the carburetor and Nissan's SCV system. It's resistance that increases velocity also. You have to imagine air flow as if it were water. Imagine putting your thumb over a garden hose outlet, decreasing the diameter of pipe but still allowing flow.

Still flow...yes, but creating back pressure at the same time most likely. A turbo car would probably take negative back pressure if it could, thats how much it doesn't like it.

[Neejay]

Still flow...yes, but creating back pressure at the same time most likely. A turbo car would probably take negative back pressure if it could, thats how much it doesn't like it.

Understood, but I'm trying to gauge are we talking about 2-3hp, 10hp, 20hp? (obviously roughly)

[240z4u]

Julio is right about having a really good flowing exhaust, but at your power levels and flow requirements at this point I would bet $20 you aren't giving up any power.

[SullivanRacing06]

go spend the 20 at a exhaust shop and have them weld a straight 3" piece of pipe in the place of the res