47-59 X or H Pipe, another choice?

[Stepside Jim]

I'm not gonna finish this in one post, this X or H pipe issue has been talked about over and over.

My situation, I had an X pipe, it wasn't the most efficient design for flow and scavenging, although flow mattered, I wanted my side exhaust exits to bark with 8 cylinders, not 4 cylinders per side.

I believe most people's choice of X or H is based on the space they have to work with, I believe most people settle with H because of lack of space, such as I am now up against with the Transmission swap I'm doing.

I don't like the idea of giving up my 8 cylinders sound per side because of a trans upgrade. The thought of losing something I like to add something else I like doesn't settle for me. I want both to stay.

I have more to add, perhaps a solution, but I want to know if my thinking of others choices are as I suspect, space being the final deciding factor for most.

[mr48chev]

I don't think you will get better bark at the tailpipe tip with either, the concept is to smooth out the exhaust pulse and allow smoother flow all together. The first H pipes I remember seeing were on factory dual exhaust Fords with FE engines in them. If anything it quiets the exhaust down a bit because the flow is evened out and balanced.

[Stepside Jim]

mr48chev, Thanks for the reply. I apologize, I used the word '' bark"", my bad.

I suppose the better word would be ''rumble'', or maybe ''exhaust tone''.

I do understand that by using a X or H pipe the peaks of the exhaust tone will be smoothed out by the opposing pulses cancelling each other.

[mr48chev]

Getting the Just right exhaust tone is one of the more personal things with any hotrod, truck or custom car build. We all have our own ideas of exactly what the exhaust should sound like and what the tone should be.

I love the sound of my 71 GMC with turbos on it but that a 71 super car/super truck sound and not the sound I want for my 48 with the 292, I want that sweet straight six with dual glass packs sound I remember from Ray Riojas's 51 Chevy hardtop when we were in highschool. I don't know if I can match that with the 292 and Tom Langdon cast headers or not.

The pipes have to sound right and not just loud though. There is a big difference.

[jweb]

There are so many variables in how an exhaust sounds.

When I had my exhaust built I was told the H pipe would give more of the old school sound and the X would be like a modern V8.

I have a stock 5.7 LS, short headers, an H pipe, Magnaflow mufflers and 2.5" exhaust all the way back to the rear bumper.

My truck isn't loud but has a nice sound with very little drone.

I added electric cutouts for the times I wanted it loud but it just sounds like an old truck with holes in the muffler when I open them. So they don't get used.

Not sure if any of this helps. Everyone's set up is a little different.

[Stepside Jim]

Ok, thanks for the replies. My main focus was not so much the sound, but how some vehicles are hindered by design that they can't use either an H or X pipe.

For example, my situation, I prefer to use an X pipe but my transmission upgrade has taken up the space needed to use a normal X pipe.

I've designed a way to use an H pipe yet it passes the exhaust similar to an X pipe.

My idea may already be out there, I just haven't seen it yet.

It's all about what's hiding within the H pipe in the pic below.

[e015475]

I've never tried it, but I've seen a short Flowmaster 10 with dual inlets and outlets used in place of an H or X pipe.

Something like this-

https://www.jegs.com/i/JEGS/555/30246/10002/-1

There's one installed on a LS motor in this video - the H, X Dual Muffler starts at about minute 4

https://www.youtube.com/watch?v=1ZsTrlwB0E0

[dsraven]

pipe size will also make a difference as it affects the pulse scavenging. a smaller pipe makes the air flow faster so that little vacuum behind the pulse will scavenge the pulse behind it better. gotta match pipe size to engine size and rpm you wanna run at the most. it's a science.

[Stepside Jim]

Lol. somehow I knew you'd show up dsraven .


e015475, Thanks, I checked out the links, I will keep the dual inlet/outlet muffler in mind.

dsraven brought up scavenging and creating a vacuum to pull air/exhaust. These are the key things that I think are lacking in an H pipe situation. I just see an H pipe as a buffer, some small area that absorbs pulses and through this absorbing pules process the 2 banks of cylinders are balanced.

In the end we've balanced by buffering the two banks but we haven't created any scavenging or crossflow equalization.

I would think that a situation where exhaust could freely pass from side to side would be much more efficient than dead end buffering.

Once again, the X pipe does this crossflow/mixing/scavenging by its design but some of us do not have the space for an X pipe and are stuck with settling with the H pipe as I show in my picture.

Hang in there, I've got a solution.....I'm just seeing where people stand on this topic, and get to what separates the H from the X in theory and principle.

[mongocanfly]

i think Paul from fabrats is installing one like e015475 showed

[R&B51]

Why not both!
Same as serving ice cream or mixing lawn chemicals-if a little is good, won’t a lot be better?
I don’t even know what’s gonna happen with sound on my project. 51 Chevy pick up body, C6 Corvette, engine, lengthened torque tube, transmission, suspension and exhaust stock but custom frame.
The exhaust already has an H pipe in it but I’ve got a Borla duel inlet dual outlet muffler on that has an internal X pipe built-in. Original H pipe is maybe a foot and a half behind the cats and X pipe Borla muffler will be under the cab with long open pipes going from there to the back over the suspension and out the back.
Who knows what this thing is gonna sound like.
Think it’ll hurt or help performance?

[R&B51]

Ok, maybe in other discussion it’s been best to death, but you got me looking on the internet and saw that numerous high performance cars come factory double crossovers different types including Mercedes. This comment in Mustang forums:
“Dual x pipe has been shown to add 75% as much torque as HP when doing cat back systems, that is why corsa has gone to it. The main problem when doing exhaust is gaining HP but not torque or in some cases even losing torque especially on the low end. By adding a second x pipe it creates pressure on the low end yet smooths out the exhaust pressure as it increases assisting with drone. Their cat back xtreme system on the c7 shows a gain of 20whp and 15wtq.
So, what is your secret plan?!

[Stepside Jim]

Ok, remember this, not everybody's needs are the same, I had certain needs I wanted to fill and I believe I achieved my goal.

Short review...

1) My exhaust exits through the step side bed steps. I wanted all 8 cylinders to sound through both exits.

2) I don't have the space anymore that allows for an X pipe, but I do have the perfect spot for an H pipe.

3) I want an X pipe, I now have a stretched X pipe in theory. I call it StreX.

4) I wanted to balance the exhaust by pulses freely passing from side to side, not by slamming into each other like in an H pipe.

Pictures in the next posts...

[Stepside Jim]

Surgery required. Cut to length your H pipe and cut the contour of the pipe it will fit to also. (Fish mouth)? Slice the pipe lengthwise evenly on both sides.

I used 18 gauge sheet metal. For 2 1/2 inch pipe I cut it 2 5/8 wide x the length of the H pipe plus about 4 inches. This sheet metal will divide the 2 halves of the H pipe into 2 D shaped passages.

The over hang of sheet metal on each end will support the wind vanes and allow you to draw where the vanes will be. I marked mine to 1 1/4 inches out, halve the distance into the 2 1/2 inch pipe it will fit into. Once I made the first vane, I made three more to match.

In the pic you see markings, IGNORE the curved line that reaches outwards.

The vanes have to be made so they will fit into the contour of the pipe they will be fitting into. I purposely made my vanes slightly larger then when it came assembly time I flap disc fitted them.

Once the vane are tacked in place on the sheet metal, I assembled the 2 halves and the sheet metal divider and tack welded the 3 together. once tacked I flap disc ground the sheet metal to match where the pipe halves are meeting then fully welded all three together. Grind smooth and now I've got two separate passages in one pipe.

[Stepside Jim]

The 2 halves/ passages have their own vanes, on one side the vane directs exhaust into it's passage. on the other side of that passage the vane is shaped to exit the exhaust to the direction of the flow of the the other main exhaust pipe.

In the 2nd halve/passage, the vanes do the same thing, directing exhaust in, then out, but in the opposite direction thus balancing the exhaust on both banks.

One could argue having this vane setup inside the pipe could be a restriction, perhaps...

On the other hand, one half of the restriction isn't blocking exhaust, it's redirecting it.

On the other passage, the outlet, the exhaust passing by it is creating a vacuum effect helping to pull exhaust through the H pipe.

[Stepside Jim]

One more pic of the business end. The other end is the same except for the vanes are pointing the opposite direction to cause an inlet and outlet effect.

Here we are, building on theory, isn't that where most Hot Rodding stuff starts?

I'm still putting in a 4l80e w/ Gear Vendors overdrive at the moment. Next I'm gonna attempt my first gas tank build. I'm shooting for aluminum tank with internal electric pump. Perhaps I'll show my steps here also.

I won't know how this exhaust works, or doesn't work, til I get the truck running again.

I'm one who will spend hours in the shop creating something from scratch then realizing that I'm not getting the result I was looking to achieve. I'm not sentimentally involved with what I made, it usually didn't cost a lot of money. If it's not up to par, I scrap it, lesson learned, I find my next attempt is exactly what I wanted, it's all part of the process.

[Hcb3200]

Guess I got lucky. After putting in the engine and getting dual pipes straight out the back with no x or h or y and some used flowmasters from my local guy just to get me on the road. I fired it up in my driveway and two of my neighbors across the street came out side looked and me and yelled. "Don't change a thing that sounds good" haven't touched it since.

[nvrdone]

that is a fantastic idea. better patent it before the big car manufactures steal the idea. hope it works as planned.

[Stepside Jim]

Patent, yup, drawings, description, apply, then got a confirmation, now it's pending, and I have 1 year to update, change, improve the design. Been there and we're good to go.