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What is the advantage of a 2 in 1 in 2 exhaust as on 900 SS ducati's ?
Why is this better than 2 in 2 ?

sorry this is maybe a very basic question but I found an explanation of 2 into 1 vs 2 into 1 but nothing about 2 into 1 into 2
if you want to look at it is here
http://www.youtube.com/watch?v=zwjpwC0ZM44 (part 1)
http://www.youtube.com/watch?v=YfSOthdE6lU&feature=related (part 2)

thank you
anatak
It's because there is no such thing as a "2 into 1 into 2".... It is in reality a 2 into 1 with two mufflers. You could hang 10 mufflers off of the collector and it wouldn't make much difference. With Ducati, it is merely tradition and nothing more. If they really wanted to do it right, they would have two mufflers, each tuned to a different frequency. The fact that they have two identical mufflers means it's just a style thing and has nothing to do with performance. The torque curve of Ducati engines matches the 2 into 1 torque curve perfectly, therefore it is in essence a 2 into 1 system. Having 1 larger muffler is lighter than 2 smaller ones and therefore better.
 

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two into two performance

Sorry if I misunderstood you but are you saying that a 2 into 2 witch each a different frequency would be better than a 2 into 1 with one muffler on the right frequency ?

Do you know of any good sources to read about this ? Online or in book form
 

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Sorry if I misunderstood you but are you saying that a 2 into 2 witch each a different frequency would be better than a 2 into 1 with one muffler on the right frequency ?

Do you know of any good sources to read about this ? Online or in book form
Some Aprillia bikes have a 2 into 1 system where the single muffler is tuned to two different frequencies to give a broader torque band. So, I'm not sure what you mean by the "right" frequency since it's always a trade off on muffler length and pipe diameter for the reverse wave back up the pipe. I'm not even sure how much this matters after the collector.

A 2 into 2 system, as defined by the videos, is where each cylinder has it's own exhaust pipe and muffler and there is no cross over pipe between the two. This type of system gives a torque and hp peak with a dip at a lower engine speed, as explained in the video. I'd prefer the 2 into 1 system with the nice broad torque curve, but the 2 into 2 system could be better for racing where peak hp is everything.

I don't know about any books, sorry. I'm not an expert either.
 

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1 cylinder's exhaust pulses scavenge or helps pull the other's giving an extra boost or flow speed. This occurs at various rpm's or frequencies, or phases if you prefer. In other words, free torque from precise tuning of resonant harmonics, which by the way explains the Helmhozt resonator box located as part of the intake air runner. Also explains why musical wind instruments work. That's why Harley puts a crossover pipe just below the airfilter on their bikes even tho it's ugly.
 

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...That's why Harley puts a crossover pipe just below the airfilter on their bikes even tho it's ugly.

LOL!! I can't remember when I last saw a new HD with the balance pipe under the air cleaner. Maybe 10 years ago? Get with the times man!!!
 

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What is the advantage of a 2 in 1 in 2 exhaust as on 900 SS ducati's ?
Why is this better than 2 in 2 ?

sorry this is maybe a very basic question but I found an explanation of 2 into 1 vs 2 into 1 but nothing about 2 into 1 into 2
if you want to look at it is here
http://www.youtube.com/watch?v=zwjpwC0ZM44 (part 1)
http://www.youtube.com/watch?v=YfSOthdE6lU&feature=related (part 2)

thank you
anatak
Cuz it's like sleeping with siamese twins...twice the blow at the end but they're both on the same wavelength so it's even better than a threesome:) Hehe:)

edit: and no, I have no valid answer, but I'd guess it has to do with tuning/equalization/pulses etc...
 

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I find it interesting that even in World Superbike racing, Ducati used twin mufflers on some bikes. I guess the rules required them to keep it the same?

Anyway, I have a friend who is a good welder and was willing to make a custom exhaust for my bike. This is it so far:

The welds have not been ground smooth, and there is a clamp missing from the muffler pipe, but otherwise it's mostly done. I decided to put the exhaust on the left side of the bike to keep the heat away from the rear brake parts.
 

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You might find that 2 into 1 eats CF cans. Remember there is twice as much heat and twice as many exhaust pulses going through there now. Back in '97 I bought a Two Brothers 2 into 1 with aluminum can for my new TL1000s and it was a complete disaster. Within 1500 miles the packing would be blown out and the rear rivets at the endcap would pull through the the sleeve. After trimming the damaged can and repacking, the same thing happened in anothher 1500 miles. TBR was completely unwilling to admit to their inferior design (or workmanship). I bought a nice M4 2 into 2 system and never had a problem. To this day, I will never buy another TBR product again.
 

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Hello dirkwright,

would you mind showing a picture from the other side ?
thank you
I don't have one from the other side. There's no exhaust pipes on that side. It's not really finished yet. I haven't even heard it running yet. The welder says "it's loud", but so was the oem system. We did a mock up before he cut up the oem headers, and the sound was much deeper and not any louder to me. Of course, the welder rides a BMW, so maybe "loud" isn't that loud to him. Wait until I put the velocity stacks on it!
 

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You might find that 2 into 1 eats CF cans. Remember there is twice as much heat and twice as many exhaust pulses going through there now. Back in '97 I bought a Two Brothers 2 into 1 with aluminum can for my new TL1000s and it was a complete disaster. Within 1500 miles the packing would be blown out and the rear rivets at the endcap would pull through the the sleeve. After trimming the damaged can and repacking, the same thing happened in anothher 1500 miles. TBR was completely unwilling to admit to their inferior design (or workmanship). I bought a nice M4 2 into 2 system and never had a problem. To this day, I will never buy another TBR product again.
I guess I'll find out. That's a good point though.
 
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