To H-pipe or not...

[CobraSix]

I'm trying to finalize my exhaust system. Looks like I'm going to do this:

1) Exhaust kit from Mustangs Unlimited with 2 1/4" pipes, dual exhaust (in case you don't know, this will be on a Aussie head with headers).
2) Substitute the 2 turbo mufflers for Borla's.

So, there are different options on the kit. Basically, do I need an H-pipe, can it even be adapted for the 6? Thanks.

Slade

 

[Anonymous]

The V8 "H" pipe cannot be adapted to the L6....but it would be easy enough to have the exhaust shop fab up a crossover pipe between the 2 pipes.

The system I bought had the crossover pipe up just behind the tranny pan and there wouldnt have been enough room to jog the pipes over to the right to meet the header if it was installed (at least on the way I installed mine).

I never did install one on mine because several people in the past said you didnt need one with the inline 6. Somthing about the firing order I believe??

Later,

Doug

 

[rbohm]

8) you dont need an H pipe with a six and dual exhaust, however i might install an X pipe when i get that far with the falcon.

 

[Asa]

I never did install one on mine because several people in the past said you didnt need one with the inline 6. Somthing about the firing order I believe??

ran across this when researchin the FAQ

All of the above devices are V8 specific. Conventional V8 engines with a 2 plane crank have an unbalanced firing sequence in each bank. That is what gives them the typical V8 exhaust rumble. They need some sort of connection between the banks to help smooth out the exhaust. A lot of V8 race engines use a single plane crank to eliminate this problem but do so at the cost of increased vibration; others use the "bundle of snakes" exhaust where the center 3 cylinders of each bank are collected with the outer 2 of the opposing bank. Neither of these solutions is practical on a street car.

The I6 has a balanced sequence in each "bank" (1-3 and 4-6) and needs no such band-aid.

but then, FTF comes back with

A crossover pipe IS USEFUL on a six cylinder engine and even a four cylinder engine with dual exhausts. Some motorcycles use them, even two lungers. What they do is to attenuate the peak pressure rise in the exhaust system, thereby lowering the maximum overall backpressure that is seen at the exhaust valve. "X" pipe designs maintail a little more velocity than an "H" pipe but they're all good. I picked up 5HP on the dyno on a 5.0L GT mustang with the crossover connection (which was put into production) and I would think that a more restrictive truck system would benefit even more from one, although I haven't run one on a dyno. Place the crossover as close to the exhaust manifolds as possible.

i'm glad i did that FAQ, found out buncha useful stuff
hope this helps

 

[MustangSix]

The BMW M3 uses one, but that exhaust system is so highly tuned that AFIK, no aftermarket exhaust is any better than stock. The X-pipe is placed pretty far downstream. But BMW does it to specifically touch a particular rpm range, not as a balancing device.