Would this X-Pipe actually help with Power?
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
The stock H pipe on our C5's is a very POOR attempt at achieving the benefit of a true balance pipe. GM Failed in that procedure
The actual hole that is CRUDELY cut into the two exhaust pipes is no bigger than the size of a quarter. There have been reports that the size and crude shape of the hole causes cavatation at various exhaust velocities and causes a unique noise that sounds like keys jiggling. There was a Technical Service Bulletin that explained it and directed the dealer what to do about it.
I took care of it the easy way.... I changed out the entire exhaust system on my ZO6.
The X pipe doesn't really add much power as much as it helps remove some of the babble and gurgle that we get in our exhaust on deceleration.
The actual hole that is CRUDELY cut into the two exhaust pipes is no bigger than the size of a quarter. There have been reports that the size and crude shape of the hole causes cavatation at various exhaust velocities and causes a unique noise that sounds like keys jiggling. There was a Technical Service Bulletin that explained it and directed the dealer what to do about it.
I took care of it the easy way.... I changed out the entire exhaust system on my ZO6.
The X pipe doesn't really add much power as much as it helps remove some of the babble and gurgle that we get in our exhaust on deceleration.
Race Director
Joined: Apr 2007
Posts: 11,152
Likes: 890
From: South Western Ontario
You're reasoning that the X-pipe giving a straight shot for the exhaust to pass to the other side makes the best placement is wrong.
I'm certainly not an exhaust engineer, but building the exhaust to provide the most scavanging seems to provide the most power. I believe the ideal placement has something to do with the flow velocity in the pipe. Something like the location with the highest flow velocity and then the exhaust pulse in one side "pulls" on the other side.
Finally, posting a picture of the XSpower system as "proof" that the X-pipe should be at the headers doesn't mean much. The LG systems make good power and their X-pipe is about 1/2 way down the mid-pipe after the cats. I have XSPower headers and I would expect their design doesn't help the midrange power as much as possible with the shorter tubes compared to some other headers. Sometimes the X is just put where it's easy to place.
I'm certainly not an exhaust engineer, but building the exhaust to provide the most scavanging seems to provide the most power. I believe the ideal placement has something to do with the flow velocity in the pipe. Something like the location with the highest flow velocity and then the exhaust pulse in one side "pulls" on the other side.
Finally, posting a picture of the XSpower system as "proof" that the X-pipe should be at the headers doesn't mean much. The LG systems make good power and their X-pipe is about 1/2 way down the mid-pipe after the cats. I have XSPower headers and I would expect their design doesn't help the midrange power as much as possible with the shorter tubes compared to some other headers. Sometimes the X is just put where it's easy to place.
Tech Contributor
Joined: Dec 1999
Posts: 32,910
Likes: 2,402
From: Anthony TX
CI 6,7,8,9,11 Vet
St. Jude Donor '08
You're reasoning that the X-pipe giving a straight shot for the exhaust to pass to the other side makes the best placement is wrong.
I'm certainly not an exhaust engineer, but building the exhaust to provide the most scavanging seems to provide the most power. I believe the ideal placement has something to do with the flow velocity in the pipe. Something like the location with the highest flow velocity and then the exhaust pulse in one side "pulls" on the other side.
Finally, posting a picture of the XSpower system as "proof" that the X-pipe should be at the headers doesn't mean much. The LG systems make good power and their X-pipe is about 1/2 way down the mid-pipe after the cats. I have XSPower headers and I would expect their design doesn't help the midrange power as much as possible with the shorter tubes compared to some other headers. Sometimes the X is just put where it's easy to place.
I'm certainly not an exhaust engineer, but building the exhaust to provide the most scavanging seems to provide the most power. I believe the ideal placement has something to do with the flow velocity in the pipe. Something like the location with the highest flow velocity and then the exhaust pulse in one side "pulls" on the other side.
Finally, posting a picture of the XSpower system as "proof" that the X-pipe should be at the headers doesn't mean much. The LG systems make good power and their X-pipe is about 1/2 way down the mid-pipe after the cats. I have XSPower headers and I would expect their design doesn't help the midrange power as much as possible with the shorter tubes compared to some other headers. Sometimes the X is just put where it's easy to place.
To properly place a X, H or what ever balance pipe, you have to find a location in the exhaust pipe/s where the cylinder pulses resonate. I read an article where an engineer put a stripe of crayon on the two exhaust pipes. The places where the wax burns off first are the desired spots to place a cross over..
I don't have the time, equipment or cash to design an exhaust so, I let the experts do it and purchase their products. Some how that a lot less money.
I'm sure GM put the H pipe where it is for a reason and it made some sort of a difference in performance, efficiency or sound. Other wise,, it would be there ($$$$$$)
Will inserting an X pipe in that exact same location help, hurt or just waste time and cash. WHO KNOWS.
I do know that just adding an X pipe does change the sound of the exhaust note for the better (IMHO)
Bill
Le Mans Master
Joined: Mar 2002
Posts: 8,466
Likes: 51
St. Jude Donor '17
I have always known that an x-pipe right after the collectors improves scavenging .
Why would you think having an x-pipe further away from the cylinders would cause it to work "better".
Last edited by Got uid0; Apr 29, 2012 at 05:35 PM.
