Scott Tilton writes:
>Furthermore . . . any ideas what the exhaust note will sound like? One pipe
>will be cyls 1 and 4 and the other (obvisously) would be cyls 2 and 3. Id
>hate to go to all that trouble and have it sound like crap.
>
>And finally . . . any comments about the efficiency of the system?
First off, what is the firing order? You probably want opposing cylinders to
go to the same pipe, so that if firing order is 1-3-4-2, you do want 1 & 4
into
one pipe, and 3 & 2 into the other.
The main good thing about headers is the scavenging (extractor) effect.
If the length of the runner into the junction is right, at a certain rpm the
exhaust pulse from one cylinder will create a low pressure wave which
travels up the other runner and helps evacuate that combustion chamber.
The determining factors are pipe length (and diameter?), and number of
sympathetic exhaust pulses per second. Basically it's the same as
tuning a pipe organ. The longer the pipe, the lower the rpm it will be
tuned to extract at. And a 4 into 1 will be different than a 4 into 2, or
a 4-2-1 arrangement. Muffler choice will also effect exhaust tone.
Dave Williamson (silikal@aol.com) Spits in bits
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