Exhaust mod?

[dunlop0_1]

On egay i saw a set of monster header pipes which had the cross over join bit in the middle cut out and a plate welded on either side, if that makes sense. Does anyone know if this is of any benefit?:scratch:

Thanks.

[eonan]

Have a read of this thread on the DML :thumbsup:

http://www.ducatimonster.org/smf/index.php?topic=88195.0

[Gilps]

Don't do it!!! This is a mod which Rich at Louigi Moto had made to a couple of bikes. Basically he cut the centre piece out and rewelded it creating one large chamber which then split off back into the two pipes. He figured the new chamber would allow the pressure to balance out and would create better flow. We put one of these modified pipes on Domski's bike. We couldn't get the damn thing to rev much above 9k, it just fell like it was hitting a wall. We swapped back to the original headers and problem solved, now revs to 10500. Rich now remembers that his partners 900 Monster also hit a wall at 9k and won't rev above, so is going to switch that back to standard headers too.
We reckon it sets up some kind of pressure echo in the chamber and causes back pressure which prevents the exhaust flowing properly.

[eonan]

Yep...there's a good reason why they designed it that way ;)

[Nickj]

You could make that work BUT....
Yer 'box' would act as a resonant chamber, you'd need to tune the volume and to a degree the shape properly else the standing waves could severely restrict the gas flow out of the exhaust. It sounds like the one made set up a wave that was trying to push the exhaust gases back into the engine at a specific pulse frequency (engine revs).
Standing waves are like the single instrument notes that get louder and quieter as you walk towards or away from the source, they are kind of tuned to the building.
Had a very mis-spent youth playing with 2T's and spannies.

[Stu Pid]

You could make that work BUT....
Yer 'box' would act as a resonant chamber, you'd need to tune the volume and to a degree the shape properly else the standing waves could severely restrict the gas flow out of the exhaust. It sounds like the one made set up a wave that was trying to push the exhaust gases back into the engine at a specific pulse frequency (engine revs).
Standing waves are like the single instrument notes that get louder and quieter as you walk towards or away from the source, they are kind of tuned to the building.
Had a very mis-spent youth playing with 2T's and spannies.

Oh my god, I thought I knew nothing about bikes, now I know I definatly know nothing about bikes.

[jerry]

Dont worry Stu Pid with an attitude like your of asking sensible questions and a willing to learn can do you will soon know all you need.

''The more I know the less I understand , and the more I understand about life the less I understand''!!!!!!

cheers mate .

monsterman