Xpipe vs Hpipe, The "Battle Royal" rages on.

Papa_D · 07-12-2008, 05:12 AM

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I am getting the Dr Gas Xpipe as many of you may know and I believe I will be happy with it but I never stop researching.

I combed the web again today and found many conflicting opinions but very little hard data other than seat of the pants feel or unsubstantiated drag strip claims with no Density Altitude (weather data) data to back it up.

I found a couple of web pages hailing the Xpipe as the end all be all but even though I bought one, I am not convinced they are "all that" and there are even claims that both the Xpipes and Hpipes are a waste of time performance wise and may even hurt rather than help.

I think in the end I went with the Dr Gas Xpipe because the NASCAR guys run them and it offered the sound and noise level I wanted but with all the negative press they are getting, it makes me wonder how much the crossovers are actually worth HP wise and if it wasn't for the fact that the NASCAR guys run them, whether I would still be convinced they were worthwhile for anything other than the sound factor.

Obviously my vote goes to the Xpipe because scavenging seems to be a very real phenomenon and I believe that the Xpipe does a better job of that due to the deceased angles on the Xpipes vs the Hpipes. This is substantiated by a couple of sites including the Dr Gas exhaust site where they make 90% of all NASCAR exhausts for the different racing series.

So the question is, do you believe the crossovers work and if so, how much do they help and which one offers the best chance of a quick quarter mile, the X or Hpipes?

Don't be shy, it doesn't matter what your opinion is, you will have company no matter what because the subject is surrounded by controversy and the debate rages on and on.

The first and last links report the Xpipe to provide better torque and HP numbers than the Hpipe when the common belief is that the Hpipe offers more torque and after reading about Hpipes on the Dr Gas site, I think it may depend on the application.

http://www.pontiacstreetperformance..../exhaust3.html

http://carcraft.automotive.com/9741/...ion/index.html

http://www.calgarystreetrides.ca/for...ead.php?t=1097

**Blackbeauty** · 07-12-2008, 05:41 AM

Papa... links don't work for me... My gut feeling would be the X-pipes would flow smoother. That's just a common sense, logical approach. I have read that the H-pipe is mainly to equalize the pressures and allow the two exhausts to share the mis-timed exhaust pulses, and the X-pipe is the evolution of that "sharing" theory but with increased airflow characteristics. I would think the X-pipes would create less turbulence in the exhaust stream and be a cleaner exit for the engine to push the air out.

How do you plan to integrate the X-pipe? Are you building a jig to hold the pipes in alignment while they're cut and rewelded?

**Blackbeauty** · 07-12-2008, 05:52 AM

Papa, you seen this one?

http://www.stangnet.com/Tech-Article...eakdown-5.html

This seems to be the presiding opinion in the Ford and Stang camp.

**Blackbeauty** · 07-12-2008, 05:55 AM

Hmmmm... interesting.... This is a pretty good explanation of the different theories.

http://www.mustangforums.com/m_1028601/tm.htm

Papa_D · 07-12-2008, 06:29 AM

Quote:

Originally Posted by Blackbeauty

Papa, you seen this one?

http://www.stangnet.com/Tech-Article...eakdown-5.html

This seems to be the presiding opinion in the Ford and Stang camp.

I sure did, in fact it was a real challenge to find anything about an Hpipe or Pro chamber that wasn't on a Mustang site, lol.

From the other stuff I read, it would seem that the different engine setups like different pipes and although the first link (I fixed them) says that the Xpipe beat the Hpipe badly, it wasn't on a Mustang.

As far as the pro chamber goes, that to me would act as both an Hpipe and a header terminus to send the negative pulse back to the cylinder to help evacuate the exhaust gases.

**Blackbeauty** · 07-12-2008, 06:31 AM

Yeah.. I was over on the Nova sites and all those guys had were questions with nobody answering.... Glad I don't have one of those!

Papa_D · 07-12-2008, 06:42 AM

Quote:

Originally Posted by Blackbeauty

Hmmmm... interesting.... This is a pretty good explanation of the different theories.

http://www.mustangforums.com/m_1028601/tm.htm

Thanks for that my friend, I had read that one a while back but it's a good read, so I read it again, lol. The only part he left out was that the box seems large enough to act as the header terminus and that, in and of itself, would increase scavenging.

It may be a large enough change in cross sectional area for the exhaust system to see it as "open air" and treat it like the tip, sending a negative pressure wave back to the cylinder and evacuating the spent gases or " scavenging."

If it weren't for the stuff in the way and the fact that I wanted to run cats, I would probably give this a shot but I'm not going to hack into the Nismo any more than I have too, lol.

Papa_D · 07-12-2008, 06:48 AM

Quote:

Originally Posted by Blackbeauty

Yeah.. I was over on the Nova sites and all those guys had were questions with nobody answering.... Glad I don't have one of those!

Lol, no doubt, the Mustang sites abound and everything else is playing second fiddle.

I'm surprised that not much came up in the way of the Camaros when I was searching, I wonder if the Camaro guys can read, lol.

Disclaimer: I have nothing against Camaros or their owners. Anything said in the above post to disparage Camaros or their owners was done with comedic intent and in no way reflects my true beliefs about said cars or their occupants, lol.

Mychael101 · 07-12-2008, 09:56 PM

Everyone in the LS1/LT1 camps know is an off road y-pipe and SLP catback with tuning from LS1edit.

Hawaiianbasshead · 07-12-2008, 11:19 PM

pretty sad

I'm very curious between the two also, looking at flow characteristics, I'd think the X-pipe would flow better. BUT I also think some vehicles would benefit from the added backpressure of a not so well flowing H pipe, depending on desired results maybe even type of motor or such. I don't know at all enough to make an informed decision on which would be better on the T. BUT I'm sure simple testing could confirm. I'd do dyno, 1/4 and 1/4 mile while towing a heavy load to test personally