I notice more people are going with a X pipe on their true duals than a H pipe. Is there a reason performance, clearance, or sound wise or is the X pipe just for looks??

 

off the top of my head i think its x-pipe for more power/tq and h-pipe has a better sound. i went with x-pipe

 

Im going with jrp on this one,

also I want to go with an H pipe because of the sound and I think the gains over a ypipe will still be phenominal on a cam or h/c car.

 

More power and torque because???

 

Scavenging

 

:yup:

numbz from ls1.com, forgot his s/n here has an H-pipe setup. he makes x-pipe setups as well but i dont think he put it on his car though to test a difference.

eitherway i'll take an x/h over a y anyday , except tally has a nice y dumped setup.

 

x pipe is a little louder than a h pipe but like has been said equalizes pulses and scavenges better.

 

I to went with the X pipe in my true dual setup and I wouldnt go any other way

 

This article pretty much settled the debate over X vs H pipes for me.

http://www.vetteweb.com/tech/0307vet_xpipe/

X pipe made more hp and was actually quieter on a C5 both inside and outside the car.

 

The H pipe stops working after a certain rpm. I have read several articles where they compare an X and a H pipe. The X always made at least 10 more Hp and Tq. Picture exhaust flowing down the pipe. The H has a sharp 90 degree angle. Exhaust will take the path of less resistence and after a certain speed making that sharp of a bend will affect flow so much that it continues straight down the pipe. The X has a mandrel bent curve that splits nicely. The flow from the left can pick a path without having to affect the speed of the exhaust.

 

Thats me. I am a firm believer in the H pipe. I build X pipes too because that's what people want. I have no scientific data to back up my opinion though. GM uses a H pipe on the Vette. Ford uses a H pipe on Mustangs. Plenty of aftermarket dual systems use an H. I trust their engineers over a bunch of shadetree mechanics like us. I'll bet on a dyno test there would be no more than 1-2 hp difference. You can get variations like that from back to back runs without changing a damn thing. One thing I know for sure is that the H pipe sounds better. duals

 

In this link http://www.vetteweb.com/tech/0307vet_xpipe/ they show the x makes more hp and trq. I'm sure Magnaflow would rather build an H pipe if it were better than an X since an H is probably cheaper to build. They went with an X though because it produces more hp from the scavanging effect.

 

That isn't really a valid test because the X vs. H wasn't the only thing changed. It doesn't really show that much power gain either. A siamese X takes very little time to make; two 45* bends with holes at the bends welded together. An H needs to be notched on both ends to mate up with the other two pipes and requires two welds. A H pipe setup also uses less bends which IMO produces a more free flowing exhaust. As far as scavenging, the H evens out the exhaust pulses just like an X. It's not like the exhaust makes a 90* turn to achieve this with an H. The scavenging affect is achieved by evening out the exhaust pulses...which works with either setup.

 

They did compare just the H with new mufflers to the X with new mufflers and the X dyno'd higher. Also there X isn't 2 mandrel 90's welded together, it's a stamped piece that isn't siamese, it's symetrical.

 

In every instance we've seen, the X made more power throughout the power-band. The H is better than nothing and works very well on some combo's - but for the most power, the X is the only way to go.

An X(we only use Dr. Gas X's) is also quieter and has a more refined sound, unless put in front of a 'chambered' muffler.

 

Do you have scientific proof? Like a test where the only variable was the X or H. Is the Dr. Gas two stamped pieces mentioned above or is it two 45* 's welded together? If you have dyno results where the only variable was X or H, how much more power are we talking about???? A couple of horses???

 

I have had both but not with the same engine combos.

I did a fair amount of research for articles, and what I basically found is that H is good, but the X is a bit better for scavenging and would make more torque, not just peak per se but have stronger torque throughout the curve.

X has a more tuned sound, but they both sound good.

 

This has also been my understanding. X and H pipes are made to equalize back pressure/scavenging effect so wouldn't the X pipes design wether it be welded pieces or stamped, cause more turbulance than, like JHarmon stated, a more freely flowing H pipe?

 

Sound is an opinion thing. I like the sound of my H pipe better than X pipes. How much more power T/O the curve? A couple of ft./lbs......A couple HP. If someone has done tests where the only variable was the X and the H, let's see the results. I have no problem admitting that I'm wrong if that's the case. I'd just like to see some scientific proof. Until then I don't believe there to be that much difference in the two. myORH

 

If you think about how an X scavenges the exhaust from one pipe to the other it's clear why it makes more power, even if it's only a few hp/trq. I'm sure someone with more fluid dynamics background could explain it better but I'll try. When the exhaust pulse from the right bank hits the X-pipe it causes a slight vaccum on the left pipe, helping to pull down the exhaust on the left towards the X junction. The H does the same thing but since the pulse on the right tube is at two 90 degree turns to the right pipe it isn't as efficient at pulling the exhaust down from the left pipe. You have to think of the exhaust gas coming down the pipes as pulses or waves or air, not like a continuous flow of air. If the flow was continuous, like water coming out of a garden hose, there wouldn't be a scavenging effect and an H or X would probably hinder flow.

Here's a link on exhaust theory
http://www.accesscom.com/~knliao/exh_theory.html
It's much like a merge collector makes more hp/trq than a regular collector.
http://www.carcraft.com/techarticles/0304_merg/

This is some more technical info on an H vs an X setup.
http://www.timskelton.com/valkyrie/t...es/h_pipes.pdf