The Stovebolt Site Forums The Shop Area The HiPo Shop X and H pipes in exhaust

Here's an interesting discussion of the benefits of H and X pipes in exhaust systems to get more torque, horsepower and a quieter exhaust sound.

http://www.chevytalk.org/fusionbb/showtopic.php?tid/347995/post/new/#NEW

Link to dyne tests is at the bottom of the page that yrs posted.

Good morning Dave.

I'm getting only sound but no video at that link. What am I doing wrong?

Yar, actually, that same video is contained in the link that you posted- it's the "Engine Masters" video showing dyne tests with H & X pipes. I'll remove my link now- it must be defective.

Unicorns and leprechauns exist in the same place as actual performance gained from Rube Goldberg exhaust plumbing. There might be an advantage at some very specific RPM and load ranges, but anyone except pipe dreamers and other believers in chemically enhanced life experiences ought to know better.
Jerry

"Yar, actually, that same video is contained in the link that you posted- it's the "Engine Masters" video showing dyne tests with H & X pipes."

Thanks Dave, I did find and watch the video. The testing was done in the 3000-6000 RPM range and HP and torque data were within about 2 HP and pound feet in that range. The various pipe configurations were not tested at RPM that an engine would run in street use so we don't know how that power delivery would be effected. The guys in the video did point out that the H and X have more effect at lower exhaust gas velocities.

They also mentioned, but did not quantify, that both types of cross pipes eliminated what they called the "burble" sound of the isolated pipes. I think they mean the sound that an inboard power boat with exhaust discharging below the water line makes. That is the reason I like and use an H pipe in my street rod. It very noticeably quiets the exhaust at low RPM.

On the Chevy Talk high performance forum I have seen data from drag strip performance on this same issue that suggests that small differences in power delivery does affect who gets to the finish line first.

I've had an 'X-pipe' on for 15 plus years daily driver only vehicle. Presently the power plant is a 235, 848 head, Fentons with the X and two 30" glass pack mufflers. The main reason why I did it was to quiet down the rap I had with deceleration and it has worked beautifully. At the rpm's we run our Stovebolts there is no power gain to speak of but for quieting the vehicle it has worked well for me.

"I've had an 'X-pipe' on for 15 plus years daily driver only vehicle. Presently the power plant is a 235, 848 head, Fentons with the X and two 30" glass pack mufflers. The main reason why I did it was to quiet down the rap I had with deceleration and it has worked beautifully."

Cosmo,

A quiet exhaust note from a dual system is the reason I run an "H" pipe on the vehicles I have with home made dual exhaust systems. One "performance" benefit comes from the dual system breathing freely and the other performance benefit is a quiet vehicle that's more pleasant to drive. It seems like an exhaust system addition that has no down side. Because exhaust tubing welds so nicely it seems like an easy home shop project.

By the way, what is ODSS?

The dual exhaust I made for my 261 is short, and exits in front of the rear tire. It's a dual from the Fentons all the way to the two in-two out muffler that I picked up at a swap meet. It sounds like an old jag and there is very little rapping deceleration. I was mostly concerned about sound, not performance.

Exhuast

yar, ODSS stands for Old Dominion Stovebolt Society. There is a whole forum on here just for those members. Quite the active bunch.

"A quiet exhaust note from a dual system is the reason I run an "H" pipe on the vehicles I have with home made dual exhaust systems. One "performance" benefit comes from the dual system breathing freely and the other performance benefit is a quiet vehicle that's more pleasant to drive. It seems like an exhaust system addition that has no down side. Because exhaust tubing welds so nicely it seems like an easy home shop project."

yar, agree completely.

Norcal Dave, Yes that two in/out seems to solve it all. I just would have run it straight out the back from the muffler to get the exiting sound as far away as possible. Great looking drive train.

Thanks Cosmo. I may end up running the pipes al the way to the back after I get the truck on the road. I just wanted something different while I was building the exhaust so I came up with the idea of a shotgun style. We'll see how long I can stand the noise!

My experience below is probably unrelated to this topic, but since a 2-in/2-out muffler is referred-to, I'll post my experience with a stainless steel example I have on my 54 1/2 ton Suburban.

I have Patricks's SS dual exhaust system with a 1960 261 engine. The dual-in/dual-out muffler if mounted about 1/3 of the length rearward, and the tail-pipes "exit" over/under each-other behind the driver's side rear wheel, where the original Suburban (and, maybe all "panel-body") tail pipes exited from under the body.

This system is beautiful, and it was easy to install (well-designed/made). However, it is/was made for boys/motorcycllsts who get-off hearing loud exhaust noise. It is noisy inside and outside the Suburban, at all speeds and when "backing off". I'll eventually try to find a mufller/exhaust shop who will replace this muffler with two original-style "straight-through" mufflers.

Long ago, I had a reproduction Fenton dual-exhaust system from Jim Carter, using two original style/design mufflers and two tail pipes. It produced a mellow sound and was no louder (for occupants in the Suburban) than an original single muffler.

"However, it is/was made for boys/motorcycllsts who get-off hearing loud exhaust noise. It is noisy inside and outside the Suburban, at all speeds and when "backing off"."

Tim,

If you have a hole saw equal to the OD of your pipes it's easy to open them up for a balance tube joining them. The same hole saw can be used to make the "fish mouth" ends on the balance tube. The stainless can be welded with stick, mig or tig stainless filler. I've added an "H" to a previously isolated home made dual system and the sound was very noticeably muffled.

The muffler I picked up at a swap meet for my truck is Patrick's stainless muffler; I agree with Tim about it being too loud. It's a straight-through design with two perforated tubes that I assume have some amount of packing around them... but it is not as loud or annoying as a chambered muffler. I think it sounds like straight pipes with a slight reduction in sound. It's pretty quiet at idle though.

If you don't have a frame mounted spare tire, there is enough room under there to mount another muffler in the back, which I might end up doing later.

Thanks for the post, Dave.

You refer to possibly adding another muffler in the back?
One for each tail pipe?

Thanks,

Tim, since I don't have a frame mounted spare tire, I've got a lot of room back there to mount two mufflers, if needed.

For the sake of simplicity, I may just go with a two into one muffler, or just weld up a two into one junction to attach to a single muffler.... I'm kind of over my idea of having this truck be a straight six hot-rod. If I lose 1.2 hp, then so be it..... I've got to get the truck on the highway first, though, to see just how annoying the sound going to be. As far as I can tell so far, there is no drone, but that may change once I put the doors on and the truck bed over the muffler.

On a side note,
I put Walker stainless steel "Quiet" mufflers on my girlfriend's '63 GMC with a SBC 350, and I thought it was a perfect balance of quiet with a mild, low rumble. My girlfriend thinks it's too quiet. Had I not found Patrick's muffler for $20 at the swap meet, I probably would have installed a Walker muffler in my '50.

I really like this show. (personal opinion) But they do show the dyno sheets of almost everything they try and show on the show. Check it out and decide for your selves!

Engine Masters Episode 22