Exhaust question

[daveh]

Hi Guys which is better an X-pipe or H-pipe configuration in a mild 340 application and why?  Thanks

Dave

[Jimmy]

An x-pipe is better due to the scavenging abilities the exhaust has. As one cylinder is exhausting, another is about too, and the flow from one side exhausting creates a better vacuum to pull the next exhaust cycle with the X-Pipe design. The H-Pipe design will equalize pressures from side to side, just like the X-Pipe, but the X-Pipe is more efficient in scavenging. Just my 2-cents worth.

Big Block Jimmy

[MEK-Dangerfield]

X-pipe is more efficient. I've heard the the H-pipe sounds better though. Either pipe would be better than none.   

[the_engineers]

Wouldn't an H-pipe help with scavenging by equalizing the pressure?

[Bluemonster71RT]

Yes but no. It;s just that the X flows better than an H.

[the_engineers]

Fair enough.  Has anyone run across comparisons of no-crossover vs. H vs. X?

[dodge freak 2]

The word I hear from some pro shop guys is the crossover pipe is overrated and more in the way like for trans removal. 

[Changin Gears]

This Pontiac test compares and H to an X.

http://www.boyleworks.com/ta400/psp/exhaust.html

[the_engineers]

Sweet! 

Thanks for posting that.

[dodge freak 2]

Sweet....but how come no tests with no crossover what so ever?

[Aussie Challenger]

  Best results are obtained with the "X" pipe.

  If you want a cool sound then the "H" pipe is best.

  No crossover pipe at all is worst option.

  There has been tests done however I don't have a reference for them, I think TTI have some info on their web site.   

[shadango]

The word I hear from some pro shop guys is the crossover pipe is overrated and more in the way like for trans removal.

FWIW, the X pipe on my Magnaflow system isnt in the way. I was able to pull the shaft and tranny without removing the exhaust. ( I was worried about that.)

[72cudamaan]

The X pipe or H pipe is used to increase back pressure which equates to low end torque. If you have a single plane intake ( which is not conducive to torque) and it is a street car then you would definitely want to use a crossover pipe of some sort.

[mojavered]

When I was at the Mopars at the Strip the year before last, I asked the this same question to the Flowmaster gang.  Their response was that unless you had a high horse power engine, you will want to run an H-Pipe so that you can get enough bach pressurs.  Then they went on to say that a 3" pipe was way too big to run on a 440 an noone should run over a 2.5" pipe.  I was done with the conversation right there because I thought maybe he was a chebby or ford guy or just really did not know.  I asked the question, so I obviously could not argue with him.   I just politely walked away.  I still would like to see some kind of proof from the same engines with nothing changed but the X-H.

[cwestra]

Does anyone have any rough HP number gains from no cross-over, to H, to X?  I hear "better" but how much?