I am looking to buy beowulf exhausts but the website gives you 2 options...420mm or 380mm length. What is the difference? Would the longer ones be a louder deeper sound or would that be on the shorter cans? They are both the same price.

Cheers

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From my understand the shorter one would be louder to there effectively being less of a silcener ie mean more sweet sweet sounds

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Plough on

If you haven't purchased them already, i'd recommend the 420's- with single's you want a longer length can as the engine relies on big pulses of power from the single to be dissipated- too short an exhaust and you loose power.

I've an interesting point of reference on this- if you check some of my other posts I had a custom set of exhausts made for my xtx, small diameter twin stacked end cans, running about 380mm in length.

I've recently put the standards back on-partly because I'm considering selling it. I can't believe how much better the bike is now. Lessons I've learned is 1) the XTX has the exhausts either side for a reason, the handling and balance get disturbed when it's all one side more than most bikes. 2) My exhausts were VERY loud, and that disguised the drop in perfomance I'd actually experienced, despite the new system weighing about half as much as one of the stock cans-this bike actually deals better with the extra weight.

I've still decided to run the stage 1 & 2 air filters and p/c v. If I was starting out modding the XTX again, these are the only mods I'd get

Phew long reply

The silencer length is considerably less critical than the header length or total exhaust length when it comes to tuning an exhaust (and pipe diameter or course). As Maxwell implies, the silencer is just that, a sound deadening devise.

Trouble with two-on-one side setups has always been each pipe from port to outlet is going to be a different length (unless you have a collector box, a 2-1-2 setup, or have loads of very expensive serpent-like bends to compensate). Each exhaust valve then ends up operating under slightly different conditions (scavenging and back-pressure), resulting in loss of torque and consequently power. I seem to remember the very first Metal Mule 2-1 system (very unequal length headers) supplied to Damian I'Anson (ex Bike magazine) for his Himalayan altitude record attempt lost midrange and had various other "holes" in the torque curve, which he could only partially correct with a Power Commander on the dyno, and put down to the header design.

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I agree with you Pleiades, and the header length is the most critical part, as can diameter, however from speaking with the fabricator who created my system, he was explaining that whilst on multi cylinder bikes the end can length is more sound based, the length does have a more pronounced affect with singles, hence why the XTX ones as standard are so long.

Interesting about the metal mule one, I assume they since revised their design?

Mine was based on equal measurments to the standards, and this did result in interesting routing, however I hadn't considered the point you made about the port to outlet length. On my system they are quite different in shape, I guess that will be resposible for the loss

Thanks for sharing the information.

No. They are still exactly the same design as they were. You can see evidence of uneven gas pressure and temperature distribution in most MM systems fiitted to XTs for any length of time, as they have significantly different discolouration on the rhs (shorter header), when compared to the left.

But to give MM some credit they were never sold as "performance" systems, they were/are marketed to aid ground clearance and reduce weight (which they do very well).

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