X-Pipe vs H-Pipe

[71400lb]

Sorry if this topic is old, but I couldn't get anywhere with the "search" option.
Anyway, is anyone using an X, or H Pipe on their small block Chevy engines? How much horsepower and torque does each pipe gain? Is it worth it?

I have a 1971 Chevy Cheyenne C/20, 2WD, 400 SBC, 4 bbl, dual Flowmasters(quite ones, not sure what series), 400 Turbo Trans, 3.73 Open Rear end.

I'd like to add Dynomax Turbo's and either an X or H Pipe...any opinions for me out there?

Thanks All,

Rick
1971 Cheyenne C/20

[Old Yeller 1970]

I have a 2 1/2" exhaust with an H-Pipe. I hear they are not as good as an X-Pipe but it was easier to install the H-Pipe, because I did it by myself and I wanted it to clear the transmission just in case I ever have to pull it.

I figured an H-Pipe is a lot better than nothing and given the size of my cam it helps the engine idle better, smoother and lower RPM's (600 to be exact), than would have been possible otherwise.

I know it gains HP with the H-Pipe vs no H-Pipe but not sure how much. In my application it was definitely worth it.

[shelby987]

Dang, I was just looking at this last night, I just bought an awesome book, how to build horsepower, its by the authors of hot rod magazine, and they have all of their write-ups in there.....there is one where they compare the two on a small block with side by side numbers......one is good for torque, and the other hp.....I will get the book when I get home, and try to post the information on monday if you still need it!
p.s. this book is an awesome reference guide.....I will be using it to ensure my $$ is dished out to the proper modifications....seat of the pants...''butt dyno'' is great, but a real dyno is even better!

[BowTieMan]

I have Dual 2 1/2" pipe and a h-pipe. The h-pipe added a noticable difference in power for sure. But I heared an x-pipe gives more but I also did my exhaust my self so I just went with the h-pipe. And I can tell you now any truck or car I ever own with duals will have either an h or x pipe for sure.

[PICKMUP]

I just read an article on an X pipe install and dyno tests on a C5 Vette with a new good HP exhaust system. The X pipe was good for 2-3 hp & 2-3 lbs torque. That makes it about the last thing I would hang under one of our trucks. Not much bang-for-the-buck! You can get a lot more results from: cam, intake, carb, gears, etc. jmho

[86swb]

I just do not understand how an H or X pipe gives you more horse power? I have been told those pipes also quiets the exhaust down. shelby987 would like to hear more on what that book says.

[llegos]

it balances out the exhaust, so you have equal flow in the pipes. I will be gettin an X when i get my exhaust system done.

[shelby987]

The book stated during their build of a mild small block, the H-pipe was good for an extra 7 ft-lbs of torque over the X-pipe, while the X-Pipe made an extra 5hp over the H-pipe.....both showed gains over a stock dual exhaust....I guess its all in which you want more of.

p.s. if memory serves, the gains didn't shift RPM levels....max hp and max tq were at the same point RPM, just 5hp and 7ft-lbs higher respectifully.

[71400lb]

Thanks for posting the data Shelby987,'

Did they give both hp and tq increases for both, or just tq for the H and hp for the X? I'm thinking that if the H got 7 more lb ft tq, then hp must have gone up at least a few as well, right?
I'm curious to see the overall gains from each application.

I'm leaning towards the H pipe right now.

Also, my pipes exit to the side behind the rear wheels, so there's a bend obviously...what if I re-configure them straight out the back under the rear bumper, would that gain me anything, do you think?

Thanks,
71LB400

[66`shortbed]

Originally Posted by 71400lb

Sorry if this topic is old, but I couldn't get anywhere with the "search" option.
Anyway, is anyone using an X, or H Pipe on their small block Chevy engines? How much horsepower and torque does each pipe gain? Is it worth it?

I have a 1971 Chevy Cheyenne C/20, 2WD, 400 SBC, 4 bbl, dual Flowmasters(quite ones, not sure what series), 400 Turbo Trans, 3.73 Open Rear end.

I'd like to add Dynomax Turbo's and either an X or H Pipe...any opinions for me out there?

Thanks All,

Rick
1971 Cheyenne C/20

i just run dual glasspacks

[shelby987]

Well, basic fluid dynamics states that anything you do to reduce turbulence is going to improve flow.....i.e. the straighter the pipe run, the better the flow will be (also the same logic used for mandrel bent pipes....less restriction and turbulence). engineerd!
The gains you will see however will likely be minimal at best, unless you have a pretty radical 90 degree bend to exit behind the rear wheels......the fact that you have to snake the exhaust up and over the axle is probably more of a backup than anything else.....I wonder if exiting in front of the wheels would give you better gains (again, either will likely only be marginal).
Give me till tomorrow, I will try to post all of the numbers from their exhaust setups....it includes comparisions for different exhaust sizes as well

[71400lb]

"Give me till tomorrow, I will try to post all of the numbers from their exhaust setups....it includes comparisions for different exhaust sizes as well"

I appreciate that.

Thanks again,
Rick
71400lb

[70rs/ss]

X and H pipes are moe about equalling out the exhaust pulses than anything. In the perfect world we would all have hand built equal length headers that go two into four so that we could sqeeze all the power out of our trucks, but those headers are handmade and run $1500 and up, so the next best thing is to X or H it. This allows the exhaust waves to cancel each out and restore an equallibrium in the exhaust. Think about how the cylinders fire and then think about how one firing while one is filling and it makes sence that equalling out the pressure is good. It is not so much that it makes big HP or Torq numbers, as it is helping you to get every penny out of your upgrades by allowing the motor to be as efficient as possible.

[jimfulco]

Probably depends on the combination just like many other things do. Here's the results of a test on a Pontiac 455:

http://pontiacstreetperformance.com/psp/exhaust.html

Page 2 & 3 have the crossover info.