H-pipe location
Thread Starter
Instructor
Joined: Aug 2008
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From: Le Roy NY
H-pipe location
I've installed true duals in my 1980 using the Mid America pipes and hugger headers. I'm adding an H-pipe this winter. My original thought was to place the H where the pipes run parallel and close to each other under the passenger seat. This is where the original single pipe and cat would have been. In a recent post in another thread, a member warned that putting the H in that spot would be useless since the distance from the headers to the H is greatly different. I can understand that the exhaust pulses would not be in sync due to the lenght differences. I can run a pipe under the engine that connects at exactly the same distance from the headers, but it would be pretty low and may interfere with the oil filter removal. Any comments on H placement? How to you folks see this?
Drifting
Joined: Mar 2003
Posts: 1,608
Likes: 3
From: Canberra AUSTRALIA
St. Jude Donor '05-'06
Lingenfelters book has good advice
MP,
I have John Lingenfleters book on Modifying Small Book Chevy Engines.
On page 132 he says that it does not matter - just place the H-pipe between the header collectors and the mufflers. I added an X-PIPE and tucked i up under the rear end. I changed over to the VBP bracket on the rear end which not only lowered my suspension but gave about 1" more of clearance for an X-PIPE. A H-PIPE would fit there easy and not get in the way. JL also advises that a larger H-Pipe will give more torque (and increase volume in the pipes ahead of the mufflers) and he also advices to put flanges on the ends of the H-PIPE to make it easy to take out transmission components. This may not be so relevant with a vette as you cannot remove drive train components with the exhaust installed easilly there is just not enough room to move under there.
I found the X-pipe was exactly what I as after. I have a 2.5" X-pipe with a 2,5" Stainless Works exhaust system. It made the car quiet at cruise and makes it sound like an angry lion at full trhottle. Important where I am as noise pollution is a big deal. Not sure about power I already had plenty of that!
Cheers,
Pete
I have John Lingenfleters book on Modifying Small Book Chevy Engines.
On page 132 he says that it does not matter - just place the H-pipe between the header collectors and the mufflers. I added an X-PIPE and tucked i up under the rear end. I changed over to the VBP bracket on the rear end which not only lowered my suspension but gave about 1" more of clearance for an X-PIPE. A H-PIPE would fit there easy and not get in the way. JL also advises that a larger H-Pipe will give more torque (and increase volume in the pipes ahead of the mufflers) and he also advices to put flanges on the ends of the H-PIPE to make it easy to take out transmission components. This may not be so relevant with a vette as you cannot remove drive train components with the exhaust installed easilly there is just not enough room to move under there.
I found the X-pipe was exactly what I as after. I have a 2.5" X-pipe with a 2,5" Stainless Works exhaust system. It made the car quiet at cruise and makes it sound like an angry lion at full trhottle. Important where I am as noise pollution is a big deal. Not sure about power I already had plenty of that!
Cheers,
Pete
I've installed true duals in my 1980 using the Mid America pipes and hugger headers. I'm adding an H-pipe this winter. My original thought was to place the H where the pipes run parallel and close to each other under the passenger seat. This is where the original single pipe and cat would have been. In a recent post in another thread, a member warned that putting the H in that spot would be useless since the distance from the headers to the H is greatly different. I can understand that the exhaust pulses would not be in sync due to the lenght differences. I can run a pipe under the engine that connects at exactly the same distance from the headers, but it would be pretty low and may interfere with the oil filter removal. Any comments on H placement? How to you folks see this?
Last edited by stingry; Feb 13, 2009 at 03:48 PM. Reason: typo
Le Mans Master
Joined: Oct 2000
Posts: 8,897
Likes: 1,350
From: Santa Ana CA
Mine is right about there:
Installer thought that gave the best overall fit and clearances. System is 2-1/2" mandral bent with a 2" crossover. Was later cut and flanged for easier removal.
Installer thought that gave the best overall fit and clearances. System is 2-1/2" mandral bent with a 2" crossover. Was later cut and flanged for easier removal.
Safety Car
Joined: Aug 2001
Posts: 4,883
Likes: 11
From: North Easton Mass
I read somewhere that the way to determine the best location for the crossover pipe was to spray some paint along the exhaust pipe and run the engine. The point where the paint bubbled up was the best place to put the crossover pipe. That method might not work out well for Vettes given the tight clearances under the car. I like Lingenfelter's "it doesn't matter" philosophy better.
Rick B.
Rick B.
Thread Starter
Instructor
Joined: Aug 2008
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From: Le Roy NY
My neighbor has the small block book so I'll have a look at that. I've also heard the bubbling paint method, and that made sense. The issue is that in most cases the dual pipes are symetrical, so only the distance from the headers is in question. With the 80-82 vettes using the stock pipe routing, the passenger side exhaust pipe is a good two feet longer at the point where they converge close enough to put in the H pipe. Has anyone run this type of set-up? How did it work out?
Drifting
Joined: Sep 2006
Posts: 1,986
Likes: 21
From: Columbus MN
I read that the H-pipe should be placed as far forward as possible on a C3 Corvette. (I can't find the link to the web site now.) Here is a pic of where I put mine. There really isn't any place forward of the cross member because of the tranny mount, so this is the best I could do:
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Melting Slicks
Joined: Nov 2001
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From: Eastern US XX
Thread Starter
Instructor
Joined: Aug 2008
Posts: 110
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From: Le Roy NY
The picture looks like a modified cross member is being used. At least one I haven't seen before. On my 1980, the drivers side pipe crosses over to the passenger side to where the cat would be. That section used to be single pipe. My duals follow this path. I can get a H pipe under the tranny just behind the bell housing. That would be about a foot after the headers. It would be a little low, and would put some heat in the gearbox. So I guess the options are to do that with an H-pipe about 20" long, or go further back to where the pipes run parallel and connect with a 1 1/2" pipe. Further back means the pipes from the headers would be different lengths. Any thoughts?
Instructor
Joined: May 2007
Posts: 130
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From: Houston TX
This post is timely for me as I have just finished modifying my cross member to look exactly like MN80Vette. I've read the optimum place for the "H" pipe is 18 in from the header collectors. For me that is right at the xmember. The mounting boss for the tranny is 15in back. I was going to put mine between that boss/mtng bolts and the "front" of the xmember. It appears there is about 4-5 in of room...why not???
Also, thanks for the pic of the flange conn on the "H" pipe. A good idea. I'm buying the "H" pipe kit from Summit. It looks to have alot of flexibility as to how and where to put it.
Cheers,
Also, thanks for the pic of the flange conn on the "H" pipe. A good idea. I'm buying the "H" pipe kit from Summit. It looks to have alot of flexibility as to how and where to put it.
Cheers,
Instructor
Joined: May 2007
Posts: 130
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From: Houston TX
Correction, the location I mentioned for the "H" pipe IS 18" and why I want to locate it there. The center of the xmember is actually about 22". So the location behind the xmember is more like 27-28"...which may work just as well according to the imput so far.
Thks,
Thks,
