r1 2003 in an mk indy(not that it matters) does it matter which way the collecter goes on the 4-2-1 bit. at the mo ive got cylinder 1 and 4 going into 1 and cylinder 2 and 3 going into 1 ... if that makes any sence, only asking as ive just got back froms eds and his is cylinder 1 and 2 going into 1 and 3 and 4 going into 1

depends on the firing order i guess. if its 1-3-4-2, then i guess its right, though i don't know anything about exhaust design

1&4, 2&3 on my blade, I did look it up at the time when making it.

So it fires on the induction stroke on to'other, gases pulling more fuel in.

Yours is correct, 'eds' is easier to design and build but not right.

Regards Mark

thanks for the help

I can shed some light on this as I have tried it both ways (ooeer missus).

Initially i started out with 1&2, 3&4 pairing and it worked fine, producing around 133 RWHP on Powertechs rolling road after mapping. The following season I did an experiment and changed the pairing (as some aftermarket exhausts have this paring) and achieved 136 RWHP after another mapping session. Not a great deal of difference but an improvement.

The conclusion I draw is that either works OK and its more down to choosing correct primary and secondary lengths as much as anything, and getting your engine correctly mapped on a rolling road.

Cheers

Paul

Akrapovic seems to use 1&2, 3&4. I bet they have tried both...

Finnish Locost-racer Markku tested two otherwise identical manifolds and 1&2, 3&4 produced 7 hp more + better torque at low rews.

So even though 1&4, 2&3 might be better in theory, I believe 1&2, 3&4 is better in practise.

Al,you must be going blind with the excitement of nearly completing your build, my exhaust is 1-4 and 2-3.

ITS ALL THE EXCITEMENT

[Edited on 15/12/08 by afj]