Tech Question on X and H Pipes.. why do pipes meet?
01-14-2006, 11:04 PM
#1
Tech Question on X and H Pipes.. why do pipes meet? I've been researching a lot on true duals, and plan to swap my Borla out for a TSP X-pipe.
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.
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.
01-14-2006, 11:11 PM
#3
Originally Posted by orangeapeel
My guess would be to even out any difference in flow. It most likely creates better/higher velocity when they merge.
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.
01-14-2006, 11:32 PM
#5
think about it like this.......... if you have slow air running through one pipe and fast running through the other where they meet the fast air will basically suck the slower air through. it creates almost a vacume/low pressure point effect which will create more velocity. or atleast thats how i see it.
01-14-2006, 11:37 PM
#7
Originally Posted by bolton98TA
think about it like this.......... if you have slow air running through one pipe and fast running through the other where they meet the fast air will basically suck the slower air through. it creates almost a vacume/low pressure point effect which will create more velocity. or atleast thats how i see it.
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01-15-2006, 12:15 AM
#12
the reason i say what i said is b/c i go to NTI and me and my instructor were talking about this the other day. and im not sure if what i said is exactly rite or not but im sure its pretty close. their is something haveing to do with the exhaust pulses also.
01-15-2006, 01:08 AM
#14
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There are two parts of the exhaust that are let out of the head when the valve opens, a high speed pressure wave and a slower moving amount of gas. If the pressure wave is timed correctly with header primary lengths or x or H designs, it will help to pull the slower moving amount of gas out of the pipe. As the pressure wave moves down the pipe there is a vaccuum left behind it, based on when each valve opens the vaccuum from the last cylinder can scavenge the next one. Location of the collectors and designs like merges and tri-y's can aid in this effect. That is all I know to this point, I am sure someone can explain it better who truly understands.
01-15-2006, 09:27 AM
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Originally Posted by Stoichiometric
There are two parts of the exhaust that are let out of the head when the valve opens, a high speed pressure wave and a slower moving amount of gas. If the pressure wave is timed correctly with header primary lengths or x or H designs, it will help to pull the slower moving amount of gas out of the pipe. As the pressure wave moves down the pipe there is a vaccuum left behind it, based on when each valve opens the vaccuum from the last cylinder can scavenge the next one. Location of the collectors and designs like merges and tri-y's can aid in this effect. That is all I know to this point, I am sure someone can explain it better who truly understands.
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.
01-15-2006, 09:36 AM
#18
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Yes, back in the day people used to weld up H-pipes
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.
01-15-2006, 01:24 PM
#19
Originally Posted by jimmyblue
Yes, back in the day people used to weld up H-pipes
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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