Tech Question on X and H Pipes.. why do pipes meet?
During my discussions with a friend, a question came up in which I have no idea what the answer is..
Why do all exhaust systems have pipes from both banks that join? Meaning, the headers, whether on a X, H, or Y/I pipe, always join together and never is independently ran to the back.
Thanks.
I bet 300bhp will chime in on this thread with a superb explanation in plain "English"....It might make more sense.
I bet 300bhp will chime in on this thread with a superb explanation in plain "English"....It might make more sense.

Cool.. I like explanations in english.. lol
Yea makes sense.. I figured it had to do w/ backpressure, but maybe it has to do w/ scavenging the exhaust and making maximum EG velocity.
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The way I see it, since each longtube header does the scavenging from each cylinder bank, the junction (X or H) has the job of handling the merging/scavenging from side to side so that both banks and the entire system is in tune.
across the dual exhausts and they would set the
location, by shooting some lacquer on the pipes and
looking for the first spot to burn off, that being the
exhaust standing wave's pressure peak. Connect the
dots and the pressure will find a second way out,
use two pipes and two mufflers instead of one. The
pulses are distinct enough that you can interleave
them effectively. This is especially useful on motors
that have uneven firing orders, like B1-B1-B2-B2-B1-B1-B2-B2
rather than a B1-B2-B1-B2-B1-B2-B1-B2; the former is
even "lumpier" in the pipe.
More sophisticated would be an X that connects
the peak of one side to the valley of the other, and
vice versa. Then you might have actual scavenging,
vs. just allowing the pressure a second exit path.
Of course this resonant stuff changes with where
you run the motor. Moving the H (or X) toward the
motor favors the top end.
across the dual exhausts and they would set the
location, by shooting some lacquer on the pipes and
looking for the first spot to burn off, that being the
exhaust standing wave's pressure peak. Connect the
dots and the pressure will find a second way out,
use two pipes and two mufflers instead of one. The
pulses are distinct enough that you can interleave
them effectively. This is especially useful on motors
that have uneven firing orders, like B1-B1-B2-B2-B1-B1-B2-B2
rather than a B1-B2-B1-B2-B1-B2-B1-B2; the former is
even "lumpier" in the pipe.
More sophisticated would be an X that connects
the peak of one side to the valley of the other, and
vice versa. Then you might have actual scavenging,
vs. just allowing the pressure a second exit path.
Of course this resonant stuff changes with where
you run the motor. Moving the H (or X) toward the
motor favors the top end.
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