The gas expand in the exhaust and you dont want back pressure on a 4 stroke. The less friction losses there are the better. On racing engines they even fit draft tubes.
-------Original Message------- From: Scott Black List-Post: krnet@list.krnet.org Date: 2010/08/03 12:55:59 AM To: KRnet Subject: KR> general engine question ................................... Since the individual pipes are not feeding the exhaust Simultaneously, is there a need to increase the dia. At the collector? Scott Black Montreal
