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MG MGB GT V8 Factory Originals Technical - Exhaust balance pipe,yes or no?

Question for those of you with like me RV8 style headers through the wings but with twin exhaust system.
What are the merits if any of fitting a balance pipe between the two headers???. Also do you use pipe of the same dia as the headers or smaller.regards Adrian
adrian salisbury

Adrian...I'm using hugger manifolds & have the same question....my muffler shop said they would build my dual exhaust, paint a section of both pipes black, have me drive the car & where the paint had not burned off is where they would put a pipe between both exhausts (I believe I've told you like they told me)...said it would balance the exhaust & make it flow better...I dunno though
Tony Barnhill

What the muffler shop guys told Tony is the current hotrodder wisdom. And the balance pipe should be the same size as the exhaust pipes or no more than one size smaller.
Carl

Adrian, I fitted RV8 manifolds two years ago, together with a dual exhaust system. The idle was very lumpy and following advice from Dave Franklin at Huntsman Garage I had Mike the Pipe make up an H piece of the same diameter as the main pipes - 2 1/2 inches. To really do the job properly you need to interconnect individual pairs of cylinders across the two banks to get the maximum benefit from the interference and pressure pulses of which help to prevent loss of charge on a big overlap timing.
It isnt very practical in a road going car but let's put it this way.
My 3.5 litre V8 gives over 200 hp at the wheels on Sigma Engineerings rolling road. If you need any more information e-mail me and give your phone number and Ill give you a bell. Its cheaper for me to call from the US than vice versa!
cheers
robert pulleyblank

It does help to link the exhaust. Dr gas Makes an even better system. It is an x pipe. Muscle mustang & fast ford did a dyno test with none, an h-pipe and an x pipe on a 4.6 L I don't remember the exact numbers but it does improve everything.The X pipe flowed best, then the H-pipe FWIW mike
mike childress

I agree with the "X" pipe. I want to run with it as well. But I don't know if there is enough room for it. My ideal system is 2 1/4" aluminized pipe and dual 2 chamber flowmasters running off of RV8 style headers. So if there is enough room after installing flowmasters, I want the X pipe.
Wally
Wally Jonker

I plan to run custom exhaust the same diameter as my hugger headers..."X" pipe is interesting...has anyone done it & if so, can you help me conceptalize how it should be done...flowmasters are my choice also but is there room under there for a couple...want them as far back as possible
Tony Barnhill

Whatever the x-connect, it must be done before the expansion chambers. The closer to the headers the better. The nice thing about an H system is its easy to acrossbehind the bell housing.
robert pulleyblank

So, Robert, I just have them make an "X" out of pipes between my 2 exhausts in front of my flowmasters? the "X" vents from each pipe crossing over to the other & into itself in the center?
Tony Barnhill

Tony, If you look in the current hotrodder(rodding) ? mag They have a special article on H pipes, X the whole exhaust system. You can probably buy an x pipe at seco in H-ville 1800 633 3864 mike
mike

Tony
I'm thinking that the flowmasters will be part of the X so to speak. The exhaust comes down off the headers, and comes to the middle of the X, then on it's way back out, the flowmasters will be run, then tail pipe along the fuel tank and out the back.
I don't know yet for sure, but I'm having a custom exhaust shop do the job, so they will know how to do it.
Wally
Wally Jonker

Wally...let me know how it works out...I would like to start putting my engine in car next week..if I can get a vendor to return my e-mail so I can order engine mounts...have tried Andy several times as well as The MG Guys...to no avail...
Tony Barnhill

I was told that the Flowmasters are too think in Diameter and will hang too low under the MGB by the custom pipe shop that did my exhaust (Kustom Bendz in Montville, NJ). I have Duals(2.25")with my 215 Olds V8 4 bbl. w/2.00" H pipe crossover (just behing bellhousing) running straight out he back with turbo mufflers (I believe they are made by Dynomax). My hedders don't exit the fenders and are from Glenn Towery. The sound is GREAT!
Michael S. Domanowski

Tony,
I'm probably looking at another couple of weeks before the exhaust is installed. At least. I keep running into set backs.
But I will let you know how they do it.
Wally
Wally Jonker

Make sure your pipes kick down under the rear axle so that you dont restrict travel.
robert pulleyblank

Robert..dropped my fuel tank today to centralize..how far over did you move yours to clear muffler? do you think a Flow Master will stand on edge on either side next to tank once its centralized? or up by battery? I'm using tube shocks & have relocated my fuel pick-up to front of tank from side.
Tony Barnhill

I measured the thickness of a Flowmaster today. It came to 4.5" thick. I did not measure width. Is this that much thicker than any other muffler?

I would think that the mufflers would have to be put in front of the fuel tank to be laid down flat.

I moved my tank over about 4" or so to get the same distance between the springs.

Robert, did you have to re-locate the original hole on the valance over a couple of inches as well as cutting the new hole on the passenger side? It's looking like I have to do that to get the tailpipe to be not so close to the fuel tank (on the drivers side).

Wally
Wally Jonker

Michael, are the Dynomax similar in sound to the 2 chamber or 3 chamber Flowmasters? I am afraid the 2 chamber may be too loud. Has anyone tried the Supertrapps? I like the way they sound and they should be easy to fit.
Mark Marchbanks

Addressing Adrian's original question...Hot Rod magazine, September issue I believe, presented an excellent article about exhaust science. It was very informative, and confirms Mike C.'s comment that the X crossover pipe layout flows the best.

A related question here, has anyone looked into the possibility of mounting a side-by-side dual exhaust, ending in dual tips, along the stock routing? This would negate the need to move the tank to center. Although, I suppose the new problem would be the location of the twin silencers.
Michael Willis

Glen Towery has set up cars with dual exhaust routed on the the left hand side only.
James Johanski

Isn't there someone on one of the v8 pages that made pockets in the floor pans? Also In some street rodder books there are some very small diam. mufflers( twin inlet & outlet ) that are longer and very slender. They are supposed to rather quiet w/ a definate v8 sound.( I think they are smithy's ) FWIW
mike childress

Does anyone in the UK have a recommendation on a muffler/silencer/box that suits the MG low belly? I think I can get away with 3.5 inches max and want to keep the burble and lose the bark?
frank swinton

This thread was discussed between 26/09/2000 and 03/10/2000

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