Exhausts
 

Guys,
I'm planning on putting my exhausts underseat two into two but need some advise please. Can I simply use the original headers and fabricate two small link pipes? Some tech heads are saying I must make sure the total pipe lenghts are equal which would quite a fun task.
Help!!

Simon there have been a few different under seat exhausts done over the years
Kev Palmers had a true 2 into 2 underseat setup a few years ago, without any link between the two pipes, He made it up himself using the original headers and then cut up a set of my old R6 header pipes to make the rest.

Om 4 Stroke 4 cylinder,pipe length can prove crutial so exhasut pulses don't interfere with each other, get the lengths right and they can aid the scavenging of the other cylinders, get it wrong and they can suck out the fresh incoming charge during valve overlap and hinder power

On a 4-stroke 2 cylinder its not as critical and I can;t see any real harm in keeping the two pipes seperate.
With regard to length, think of it as volumetric length, a shorter pipe with a larger diameter and equate to a longer pipe with a smaller diameter. if your trying to match back pressures
These days you can map each cylinder seperately so slight differences in exhaust can often be compensated for

Thank you Kev. Why did you do two into one? Is that better than two into two?

Its considerably lighter, more room to work with, also look at IL4's they are predominantly 4 into 1.

there is so much conflicting info and opinions on this, when senna kindly made one from bits I had last year I lost 6bhp, seems 2-1-2 works bset on a Ducati and most twins, altho the weight saving may offset the cpl bhp it adds...altho there are some 2-1 that are bang on the limit so who knows... :puzzled:

if it helps, I'm going thru the same. New bike has 2 high level cans and I know they will get in the way. SO choice is different link pipes and reposition them, or 2-1 and get it custom made

problem I have is I can neither do it myself nor have anyone local - every place recommended is miles away and even looking thru yellow pages its still 50+ miles to anyone who can do it

The bike I bought came with a pair of Leo Vince Titanium cans. But I'm going down the same design route that I had on my 583, just different diameters. :cool:

I am lucky to have a couple of exhaust places nearby. If I get time over winter then I may get a pair of link pipes made up that are a bit further back from the pegs.

Just depends on timing and wonga

M.
PS very envious of people with underseat exhausts. Gives them more room, and the ability to shift bits around.

My bike runs a 2 into 1 using standard 900SS headers with the front cut before the splitter and then goes into a 2 into 1 coolector that is a direct copy of the standard 583 collector but in a larger diameter to suit the 40mm headers.
The collector was made by an exhaust specialist and all welds were gas purged giving a very smooth flow through the collector, where as Kew was trying to weld up a exhaust using three different stainless exhausts using Oxy Acetylene so god knows what it did for exhaust flow.

Dallas's 2 into 1 from 2010 also worked well, so much so that the can had to be changed to drag the max bhp down a bit while bumping up the mid range, His 2011 2 into 1 was pants.

A good exhaust is designed not just thrown together and Ducati spent a fair bit of time designing theres so its easy to make things worse but harder to find improvements, but as Ducati have to consider factors to do with mass production emmisions etc there is always room for improvement for a race exhaust

where'd dallas get the 2010 one done?

I Can't recall as it was some time ago it was on his 583 the year before (2009) and is now fitted to a Class A bike I have part built. It doesn't fit the Monster otherwise I would have let him have it back last year when we found he was down on power, the chances are the Exhaust mods he made after his pre season engine build and dyno setup lost him more than 6bhp