exhaust system idea

[xwiredtva@msn.com]

DG Performance makes this type of muffler for 2 stroke Motocross bikes. If
you call and ask for a brochure or visit your local motorcycle shop they may
have the cutaway. Uses a spring and a metal valve mounted into the middle of
the muffler. As rpm's increase it pushes the metal disc back opening up the
muffler to a wider chamber were the exhaust can easily go around. I'm sure
it can be done for your applications and improved somewhat. I ran it when I
raced and it gave better low end but the top end was still the same.



>Wasn't the original question about the concept of a variable back pressure
>exhaust system?  I think the idea is great, low to mid rpm gets more
>backpressure, then as rpm's increase, backpressure decreases to none.
>That's where the open pipe idea came from.
>
>If this idea were coupled with a variable valve timing setup, it would
allow
>the best performance through all rpm ranges.  Of course, it's all shooting
>from the hip theories!
>
>Jim Yeagley
>1996 Dodge Indy Ram
>See it and many others at: www.indyram.org
>1975 Pontiac Grandville Brougham Conv. (in baskets)
>webmaster at indyram.org
>jimyeagley at stratos.net
>
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