exhaust system idea

[Xwiredtva]

Not familiar with that type. The DG was a stationary valve, just moved back
and forth about 1.5" to open the chamber up, the chamber was shapped like a
bell.


>Isn't this the same as the Shotgun or Shogun , forget what it's called
>exactly that's marketed by Nology?  Looks like a butterfly valve on the end
>of an exhaust pipe.
>
>
>>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
>>>
>>>
>>>
>>>
>>
>>
>>
>
>