X-pipe really any good?
Thread Starter
Instructor
Joined: Apr 2005
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From: Göteborg
X-pipe really any good?
I´m in the process of piecing together an exhaust system and it looks like a lot of people in the US are using an X-pipe (cross pipe) for dual exhaust systems. I´ve seen comments like the "X" will equalize pressure between the cylinder banks resulting in more hp´s. I´m going to use 3" tubes all the way (incl. cats).
What I don´t understand is that the X-pipe to me seems to act as a restriction since the cross sectional area where the left and right tube meets (in the middle of the "X") will be a lot smaller than the total area of the two 3" tubes.
Using a H-pipe then appears to be less restrictive (even though most opinions on the internet seems to be in favour for the X-pipe) .
Does this make any sense-Am I missing something here?
Thanks
Goran
What I don´t understand is that the X-pipe to me seems to act as a restriction since the cross sectional area where the left and right tube meets (in the middle of the "X") will be a lot smaller than the total area of the two 3" tubes.
Using a H-pipe then appears to be less restrictive (even though most opinions on the internet seems to be in favour for the X-pipe) .
Does this make any sense-Am I missing something here?
Thanks
Goran
Drifting
Joined: Jun 2001
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From: Mass Mass
Some seam to "get" the idea, some don't.
To me, this is what they should look like.
Some that have the problem you speak about, I wouldn't consider using.
On top of the restriction, I can't imagine the two flows having to fully cross each other is good for flow.
Thread Starter
Instructor
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From: Göteborg
In this thread;
http://forums.corvetteforum.com/show...40&forum_id=48
Ramrod92 showed his B&B system and this design looks like something that should be non-restrictive as well as balancing the left and right exhaust. I think I´ll try to make a similar one if B&B wont sell their pipe separately.
SuperL98: The second pic looks like a quite good design; who is the manufacturer for this one?
http://forums.corvetteforum.com/show...40&forum_id=48
Ramrod92 showed his B&B system and this design looks like something that should be non-restrictive as well as balancing the left and right exhaust. I think I´ll try to make a similar one if B&B wont sell their pipe separately.
SuperL98: The second pic looks like a quite good design; who is the manufacturer for this one?
Last edited by bogor; Feb 8, 2007 at 10:11 AM.
Le Mans Master
Joined: Aug 2004
Posts: 5,141
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From: Metairie Louisiana
There is a scavenging effect due to the firing order of the pistons and a vacuum that is created in the pipes. The exhaust traveling down one pipe passes the x-opening and creates a vacuum that helps pull/draw the exhaust on the opposite side. I believe that the scavenging effect compensates for the smaller diameter in the x-pipe. This results in an increase of flow. I believe that is how it works. Hope I explained it correctly.
Last edited by rickneworleansla; Feb 8, 2007 at 10:18 AM.
Melting Slicks
Joined: Jul 2004
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From: Chicago Illinois
I had straight pipes 2 .3/4inch into Corsa mufflers and was I getting backfiring on deceleration big time. Put the x pipe in was a great fix for that issue. All I can say on x pipe is all the newest high performance cars have the x pipe. At least the c6 does. Im not sure about Ford or Chrysler.
Thread Starter
Instructor
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From: Göteborg
rickreeves1; that sounds logical but keeping the cross sectional area constant all the way should make it even better I think.
I did have a look at the X-pipe offered by Dr Gas (http://www.drgas.com/store/product.p...t=1&page=1)and it seems like that one have the smaller cross sectional area (and they manufacture NASCAR exhaust systems).
I did have a look at the X-pipe offered by Dr Gas (http://www.drgas.com/store/product.p...t=1&page=1)and it seems like that one have the smaller cross sectional area (and they manufacture NASCAR exhaust systems).
Thread Starter
Instructor
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From: Göteborg
With respect to placement I feel a little restricted considering the C4 underbody (lack of space). Originally I planned to run on E85 hence placing the cats close to the headers (lower combustion temp than gas). After calculating fuel pump/injector requirements I dropped this and will prob do something similar to TJWONG´s layout ( http://forums.corvetteforum.com/show...29&forum_id=48) but an x-pipe like the B&B design. I´m upgrading my fairly stock L98 to a fully forged 381 with a blower so a before-and-after comparision won´t say anything useful about the x-pipe (but I will put it on a dyno anyway).
Last edited by bogor; Feb 8, 2007 at 11:18 AM.
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Instructor
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From: Crystal Lake IL
Thanks
Racer
Joined: Dec 2005
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From: Chicago IL
There is a scavenging effect due to the firing order of the pistons and a vacuum that is created in the pipes. The exhaust traveling down one pipe passes the x-opening and creates a vacuum that helps pull/draw the exhaust on the opposite side. I believe that the scavenging effect compensates for the smaller diameter in the x-pipe. This results in an increase of flow. I believe that is how it works. Hope I explained it correctly.
my understanding too.
I use a custom 2 3/4" x pipe in my 3" b&b exhaust system.
Pro
Joined: Jul 2006
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From: chiefland fl
I'm hoping someone smarter on the exhaust sys than me will jump in
i know its measured from the collectors? back behind your collectors?, but mine doesnt have cats, (florida) they could be considered collectors.
i know its measured from the collectors? back behind your collectors?, but mine doesnt have cats, (florida) they could be considered collectors.
Pro
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From: chiefland fl
Wait......i'ts coming back to me a little, it has to do with HEAT, a water evaporating test i think, back from the headers where its COOLER, i can find out the procedure tonight, and i will post tonight unless someone else jumps in and refreshes the memory!!
Melting Slicks
Joined: May 2002
Posts: 2,670
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From: Severna Park MD
I will say that I can hear when the exhaust pulse resonance kicks in. When my car crosses over 3000 RPM the exhaust sound becomes more of a howl very like a Ferrari V8, at least listening from the driver's seat directly above the X-pipe.
Thread Starter
Instructor
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From: Göteborg
No luck with B&B; they won´t sell the X-pipe unless you buy their complete system. The Magnaflow piece seems quite nice, its stainless, price is OK ($85 at Summit) and looks like it doesn´t narrow down in the middle like some of the other design I´ve seen and maybe it even fits in the tunnel (someone already using this one that could chime in?)!
Regarding placement; I´ve heard some old tales about how to locate the best spot for an H-pipe that might apply for X-pipes as well: paint the pipes with cheap paint (no high temp paint ), drive the car hard and see where the paint is most damaged by the heat. This is the spot to place the cross pipe. No garantuee this will work-havent tried it myself.
Regarding placement; I´ve heard some old tales about how to locate the best spot for an H-pipe that might apply for X-pipes as well: paint the pipes with cheap paint (no high temp paint ), drive the car hard and see where the paint is most damaged by the heat. This is the spot to place the cross pipe. No garantuee this will work-havent tried it myself.
Drifting
Joined: Jun 2001
Posts: 1,704
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From: Mass Mass
Yes that's a magniflow (like they said) from summits website.
Found this sectioned view of it (in a mustang article).
It looks better on the inside than I thought.
I would want to keep the flow as much as possible on it's own side, and just bleed the pressure pulses between them.
Here is another one that's just not good (in my opinion) from Pypes.
As far as location, I think of H & X pipes as a "street" version of open collector length in a drag car. It's the change in area, from the one pipe to two (just like the open end of the collector) that sends the scavenging pulse up the pipe. The closer it is the the engine (shorter collector length) the higher up the rpm peak torque is, farther from the engine (longer collector length) the lower down the RPM peak torque. On these cars it's hard to get much closer to the headers than 32 inches or so, so it's a long collector anyway ...
BTW ....
A real good article by David Vizard on exhaust design here.....
http://www.superchevy.com/technical/...exh/index.html
And a corvette system he designed, at the end of the article.
Last edited by SuperL98; Feb 8, 2007 at 06:30 PM.
Melting Slicks
Joined: Nov 2004
Posts: 2,799
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From: Cape Coral FL
I had straight pipes 2 .3/4inch into Corsa mufflers and was I getting backfiring on deceleration big time. Put the x pipe in was a great fix for that issue. All I can say on x pipe is all the newest high performance cars have the x pipe. At least the c6 does. Im not sure about Ford or Chrysler.
Melting Slicks
Joined: Jul 2004
Posts: 2,695
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From: Chicago Illinois
Race Director
Joined: Oct 2001
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From: Melbourne Florida
Cruise-In IV Veteran
I had a X-Pipe installed last December...a local hot rod shop fabbed it up and installed it for $100...real nice work too...
Prior to this I my set up was long tubes and then pipes only back to stock mufflers...no cats or pre-cats or resonator or any of that stuff...I wanted to tune my exhaust to get a bit more grunt in the first 330' at the drag strip since I run a lot of 1/8 mile money events...
The X-Pipe definately changed the exhaust note but, after 10 passes at the drag strip, it does not seem to have done anything for my performance...I guess I should have left well enough alone...
Prior to this I my set up was long tubes and then pipes only back to stock mufflers...no cats or pre-cats or resonator or any of that stuff...I wanted to tune my exhaust to get a bit more grunt in the first 330' at the drag strip since I run a lot of 1/8 mile money events...
The X-Pipe definately changed the exhaust note but, after 10 passes at the drag strip, it does not seem to have done anything for my performance...I guess I should have left well enough alone...
Pro
Joined: Jul 2006
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From: chiefland fl
the correct placement of the x or h pipe is where you draw with a crayon, from front to back down the pipe, the crayon will melt closest to the engine, where you can see the start of the crayon again, is where the x pipe should go (at the start of the unmelted crayon). .
