Extractor Sizing

[VeYzZii]

What size extractors are people running here? Mostly for the custom exhaust guys. I know the Mugens are 45mm, and the Js are 50mm. I'm trying to come up with a nice set of customs for top end power, and would enjoy some input. Also if anybody has had experience of changing sizes of extractor sizes please share your results!
Thanks

[IEVAQ8]

just my 2 cents,

i have completed a supercharged s2k for a customer not long ago and it has stock headers with custom 3inch 100cel cat, and a hks 70mm single exit exhaust, and there is no restriction in backpressure...

not sure if this helps u at all...

[DreadAngel]

He's referring to the header's primary and secondary diameters I think?

4-1 if you chasing pure power but can't really help you with sizing mate =(

[VeYzZii]

just my 2 cents,

i have completed a supercharged s2k for a customer not long ago and it has stock headers with custom 3inch 100cel cat, and a hks 70mm single exit exhaust, and there is no restriction in backpressure...

not sure if this helps u at all...

Hey dude. Yea ive started to realise the standard headers are not as bad as originally thought. Ive been running 'catless' for a while now so exhaust is fine, its just the headers that i want to be getting down into. Oh man everytime supercharge and S2000 come into a sentence makes me jealous. :P


He's referring to the header's primary and secondary diameters I think?

4-1 if you chasing pure power but can't really help you with sizing mate =(

Hey bro yea I'm after sizing. I had some custom headers made imitating the standard headers. We made them 4-1 with 44mm. Coming from the almost 50mm 4-2-1 headers that i previously had its alot quieter, but with no aid of dyno i cant really tell if much has improved or if i had lost power. Thanks for the input!

[beanz]

The S2000 Mugen Development Paper section on exhaust suggests 45mm primaries

[VeYzZii]

The S2000 Mugen Development Paper section on exhaust suggests 45mm primaries

Yea, and the J's is 50mm though. On the page it says that the Mugen headers is designed for optimal mid-high rpm range power. But i thought the bigger piping, the better top end.. And 45-50 is a 10% difference which is pretty big. So im hella confused.