Topic: 4 into 1 performance exhaust

[NickO]

Can anyone enlighten me in the best design for a custom 4-1 exhaust for a our 836 race engine please?

I'm looking for ideal length/diameter of headers, etc., and best 4-2-1 configuration or whatever for maximum power.

The exhaust (less silencer), will be totally scratch-built, so in essence anything can be incorporated into the design.

All advice appreciated.

[mlinder]

Depends on lots of things, like cam duration, overlap, exhaust valve size, peak HP rpm, intake tuning..

If it's being built from scratch, use an exhaust calculator to figure out close to what you need.

[Doctor_D]

Depends on lots of things, like cam duration, overlap, exhaust valve size, peak HP rpm, intake tuning..

If it's being built from scratch, use an exhaust calculator to figure out close to what you need.

+1

Burns Stainless has a form you can fill out and have them do the calculations, or you can buy software called Pipemax.

[Sam Green Racing]

The good thing about the Island Nick is no noise restrictions, why not 4 into 4 open meggas.

Sam.

[Pinhead]

Get yourself a copy of Pipemax and build from there!!

[cb650]

It will depend on use of bike too.  Intended RPM range can dictate size and length.

[NickO]

The good thing about the Island Nick is no noise restrictions, why not 4 into 4 open meggas.

Sam.

The sound would be fantastic Sam I agree, but in terms of weight and power a 4-1 is the way to go.

Thanks for the advice guys.....priceless

[lordmoonpie]

Is weight such an issue for you Nick - 4:4 must differ from a 4:1 only by three Megas. with a full 4:4 system weighing less than 9 kilos, you'll be talking maybe a 3 kilo saving is all? Might be worth staying away from the Chippy instead

[kos]

I have a real Pop's Yoshimura hand bent/made 4 into 1 here at M3 shops and if you like I can give you the dimensions?

Note, Pop's did not make any larger cc engine than 812cc so these #'s would work well for engines below 836cc, IMHO

KOS

[NickO]

Is weight such an issue for you Nick - 4:4 must differ from a 4:1 only by three Megas. with a full 4:4 system weighing less than 9 kilos, you'll be talking maybe a 3 kilo saving is all? Might be worth staying away from the Chippy instead

It's not going to be the end of the world LMP, but 3kg's is 3kg's and on a sidecar, a 4-1 makes much more sense.

Mark, Thanks for the offer PM sent!