X pipe H pipe or side by side

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Hensley 360 built setup made 390 rear wheel hp with the H pipe and 402 tq. On the dyno, installed the X pipe, and made 412 rear wheel ho and 410 tq. My setup made more tq and hp. That's 3" to the valance with 1 7/8" TTI headers.
 
Locomotion said:
The exhaust in the pipes isn't consistently "full". The exhaust is in pulses from each cylinder - "waves".The trick is to optimize the lengths and diameters of the headers, including and X or H additions in the system.

..That makes sense.
Click to expand...
 
ir3333 said:
here's another analogy...
pull in tight behind a tractor trailer on your favourite highway and he'll
actually pull you along to some extent.Now try to get in when they are
bumper to bumper...good luck!
These exhaust systems must be "tuned" and arbitrarily welding a pipe in
between somewhere?
Click to expand...

But they aren't bumper to bumper. That's what we are all saying. There isn't a "constant" flow. It's pulses. I don't know how much easier I can state that. You don't think the cylinders constantly produce exhaust do you?

Arbitrarily welding a pipe in? It's not arbitrary. That's like saying "oh the cam lobes are arbitrary". They aren't. It's known what they do when they are put in a certain spot in a certain way. None of this is arbitrary. It's proven fact through much testing and work over decades by dozens of different race teams/aftermarket exhaust companies/professional engine builders/backyard mechanics/etc. I can understand questioning things and wanting an explanation of how they work. But when you refuse to listen to the explanation given, or don't understand it, then I don't know how to help you.
 
ir3333 said:
...can someone explain to me how a 6 inch piece of pipe can make horse power.
the exhaust can't get out any quicker.
Click to expand...

My 69 383 RR had an H pipe from the factory, and "you know Ma" She didn't spend A DIME if it didn't "do something."
 
I have tested this a bunch. If you pick up with an x or h pipe you have other issues. You are adding volume. So maybe a bigger collector. Or longer collector. Or your primary pipes are too small. Like over 370 inches and using a 1.75 or 1.625 primary. That is too small.

On top of all that, if you do find a gain it is so small, and low enough in the power curve to be insignificant.

I know some stock eliminator guys are doing it. But I know one who tried all that, but when he sized the header and collector correctly, the car went slower with the high dollar x pipe.

I know for a fact, a 340 inch, 8.5:1 compression flat lifter cam, stock 73 intake and carb that picked up with when he went from 1.625 to 1.875 primaries. Then he picked up some more when he went from a three inch collector to 3.5.

When you are dealing with production chassis, you need a bigger tube header for your displacement and rpm.

Don't drink the koolaid. Save your money and put it where you can make more power. Like rocker ratio, head work and never forget to work on the intake.
 
Not too many in racing is making more power with small blocks than NASCAR. Those guys have pretty much perfected making max HP and Tq. They have to make power from 6500-9200 Rpms. They run X pipes. They have long since gotten away from H pipes. Seems like if that was masking another problem they would have figured it out by now.
 
Mopar92 said:
Not too many in racing is making more power with small blocks than NASCAR. Those guys have pretty much perfected making max HP and Tq. They have to make power from 6500-9200 Rpms. They run X pipes. They have long since gotten away from H pipes. Seems like if that was masking another problem they would have figured it out by now.
Click to expand...

That's a bingo.
 
yellow rose said:
Save your money and put it where you can make more power. Like rocker ratio, head work and never forget to work on the intake.
Click to expand...

Save your money? You think a $6 dollar piece of pipe will break your budget? That's like arguing against the weight of the pipe.

It's just fact that h or x pipes make more power. It's been tested by high end race teams in various motor sports around the world. Guy's who have a much bigger budget than you. I'll drink the same koolaid the pro's do if it gives me the same kinda power they make. No offense.
 
Lustle said:
Save your money? You think a $6 dollar piece of pipe will break your budget? That's like arguing against the weight of the pipe.

It's just fact that h or x pipes make more power. It's been tested by high end race teams in various motor sports around the world. Guy's who have a much bigger budget than you. I'll drink the same koolaid the pro's do if it gives me the same kinda power they make. No offense.
Click to expand...

Not to mention that bigger headers, bigger pipes, side exits, etc won't always work for every build.

Track only car? Sure, anything can be made to fit/work.

Streeter/funmobile? There are always constraints and sometimes that x or h pipe is enough to allow someone to get away with headers that fit, collectors that clear, and exhaust that goes all the way out the back..
 
We were discussing scavenging,tuned Try Y,optimizing lengths,volumes,diameters
how 2 into 1 compared to 2 into 2 could work with some excellent analogies.
...Now we are "new Mustangs have them" , "Nascar run 9200 rpm" and "Hensley got
20 hp", that's O.K. and suggests they work but we stopped trying to "figure out how"
 
Going through my exhaust install now. Bought a Pypes set up and its not a bolt in job like they say it is. Having a local mandrel bending spot install and do the head pipes. After calling Pypes and talking to them about their "system" I'm having the local shop make up custom legs for the Pypes X pipe. Could have done side by side but already bought the X pipe system so I wanted to use it.
 
ir3333 said:
We were discussing scavenging,tuned Try Y,optimizing lengths,volumes,diameters
how 2 into 1 compared to 2 into 2 could work with some excellent analogies.
...Now we are "new Mustangs have them" , "Nascar run 9200 rpm" and "Hensley got
20 hp", that's O.K. and suggests they work but we stopped trying to "figure out how"
Click to expand...

me thinks these things work better on smaller engines. but, a 68, 426 hemi roadrunner came w/ an h pipe on it ! over 500 cubes , I still don't think their worth their weight, provided your whole exhaust system is big enough! . jmo
 
famous bob said:
me thinks these things work better on smaller engines. but, a 68, 426 hemi roadrunner came w/ an h pipe on it ! over 500 cubes , I still don't think their worth their weight, provided your whole exhaust system is big enough! . jmo
Click to expand...

..as suggested earlier the factory installed the H pipe because it was quieter
allowing the use less restrictive mufflers on some big block cars.
i also think your final outlets have to be large enough so each side of 4 tuned
pipes (headers) will scavenge themselves.
..Yellow Rose's post also makes some informative points.
 
I went with the H setup because that's what was done back in the day. I think the only
other deal back then was just running two separate pipes.

All of this new stuff seems like brain surgery to me but I'm old school and old (68.)
 

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Mopar92 said:
Not too many in racing is making more power with small blocks than NASCAR. Those guys have pretty much perfected making max HP and Tq. They have to make power from 6500-9200 Rpms. They run X pipes. They have long since gotten away from H pipes. Seems like if that was masking another problem they would have figured it out by now.
Click to expand...

Ok when YOU test and do R&D like nascar then I would agree. I can't tell you how many times on the dyno I have taken both styles off and made power. And at the tack.

If, and it is a big IF, you are testing cam/cylinder head/induction/exhaust then you MIGHT find power in a very narrow rpm.

I am not the only guy out there testing this stuff, and finding 99% of the results outright lies. Joe Sherman, a very well respected engine builder who worked with Edelbrock has been dyno testing this stuff way before I started. Our results, REAL WORLD RESULTS agree.

Go join speedtalk.com and then search the site for x and h pipe threads. And you will see the guys who love x and h pipes and tri-y headers and merge collectors (another joke for 99.95% of us) are the same ones who get to spend 100k in development with the latest testing equipment you can buy. All in a computer controlled atmosphere, both the dyno room and flow bench room.


Do the research before you spend your money. You can spend less money and get more than to mess with that stuff.

But some guys are slow learners, or have handicapped combinations. I suggest fixing the combo and then be prepared to spend big $$$$$$$ to do and get reliable testing.


Flame on.
 
famous bob said:
me thinks these things work better on smaller engines. but, a 68, 426 hemi roadrunner came w/ an h pipe on it ! over 500 cubes , I still don't think their worth their weight, provided your whole exhaust system is big enough! . jmo
Click to expand...

And how much do you think a 6" piece of pipe weighs? C'mon. And actually the bigger the engine the better the effect, as the exhaust needs to be bigger, so too will the scavenging effect.

ir3333 said:
We were discussing scavenging,tuned Try Y,optimizing lengths,volumes,diameters
how 2 into 1 compared to 2 into 2 could work with some excellent analogies.
...Now we are "new Mustangs have them" , "Nascar run 9200 rpm" and "Hensley got
20 hp", that's O.K. and suggests they work but we stopped trying to "figure out how"
Click to expand...

We didn't stop trying to figure out how. I just dunno how many more times I can explain it to you without you getting it? What about it are you not quite understanding ir3333?
 
Lustle said:
And how much do you think a 6" piece of pipe weighs? C'mon. And actually the bigger the engine the better the effect, as the exhaust needs to be bigger, so too will the scavenging effect.



We didn't stop trying to figure out how. I just dunno how many more times I can explain it to you without you getting it? What about it are you not quite understanding ir3333?
Click to expand...


This is exactly what I am saying. If the h pipe adds volume and it picks up HP, you either need a bigger primary tube, a bigger or longer collector, or a combination of any or all of those things.

Those x and h pipes are a band aid in most cases. Unless of course, you are trying to run down joe Gibbs for the money.

Funny thing is, I never see Comp guys or even most fast bracket cars don't use them. Unless they are required to use a full exhaust. Then maybe, because of rules, it would help.

As I pointed out, if the SYSTEM is correct, most likely you won't find a gain, and will probably find a loss.
 
yellow rose said:
This is exactly what I am saying. If the h pipe adds volume and it picks up HP, you either need a bigger primary tube, a bigger or longer collector, or a combination of any or all of those things.

Those x and h pipes are a band aid in most cases. Unless of course, you are trying to run down joe Gibbs for the money.

Funny thing is, I never see Comp guys or even most fast bracket cars don't use them. Unless they are required to use a full exhaust. Then maybe, because of rules, it would help.

As I pointed out, if the SYSTEM is correct, most likely you won't find a gain, and will probably find a loss.
Click to expand...

Getting that system 'right' is a matter of a lot of track testing - and for the guys who race, it's definitely worth chasing it down. For guys building a street pounder, it will probably never happen.

That said, it's unlikely that a cross over will ever net a loss:
http://www.superchevy.com/how-to/exhaust/0505phr-exh/
"Based on such results, we can conclude that a balance or X-pipe is always a positive asset and never a negative." - David Vizard.

So it again comes down to intended use.
 
yellow rose said:
This is exactly what I am saying. If the h pipe adds volume and it picks up HP, you either need a bigger primary tube, a bigger or longer collector, or a combination of any or all of those things.

Those x and h pipes are a band aid in most cases. Unless of course, you are trying to run down joe Gibbs for the money.

Funny thing is, I never see Comp guys or even most fast bracket cars don't use them. Unless they are required to use a full exhaust. Then maybe, because of rules, it would help.

As I pointed out, if the SYSTEM is correct, most likely you won't find a gain, and will probably find a loss.
Click to expand...

It has nothing to do with volume though. And has everything to do with merging the exhaust pulses and that effect on scavenging. We know the effect that headers have right? That the pulses not slamming into each other before the collector allows better flow right? An H or X pipe is the same. It allows the exhaust to pull the pulses behind it along. Creating a better scavenging effect.

And no, you probably won't see it on some cars. Top fuel runs "zoomie" style individual exhaust, which has been PROVEN to lose power on street/strip cars. Bigger primaries? Lose low end torque, fact. Bigger collector? Lose low end power, fact. What works on one car won't work on every car. You have to build your setup to work with itself. X and H pipes are not a bandaid. There is a proven power increase with them on common, street/strip setups. If you don't wanna put in a 6" piece of pipe because of cost or weight, power to you. But don't go around saying they don't make power. It's well documented they do.
 
It may be more of an effect of 8 and 4 firing in sequence followed by 3-6 then 5 and 7 in sequence causing concentrated pulses on opposite banks of exhaust and enhancing the scavenging.
 
I have always felt adding any exhaust system to a car made the car slower
if you got the collector length sorted.
Adding pipes makes them quieter and cost more. Never thought of exhaust as
a HP gain just something you have to have to be legal on the road.
You pay for how you want it to sound.
 
ssba said:
I have always felt adding any exhaust system to a car made the car slower
if you got the collector length sorted.
Adding pipes makes them quieter and cost more. Never thought of exhaust as
a HP gain just something you have to have to be legal on the road.
You pay for how you want it to sound.
Click to expand...

Except it's possible to muffle a high performance setup without major losses. Done wrong, a muffled setup will lose you big, done right it should have little to zero impact.

Doing it right is tough though without having all the data on-hand necessary to engineer it properly and there's no one-size-fits-all approach because the right system for a 350hp 318 is different than the right system for a fire breathing 408, and using one on the other will likely have drawbacks in both cases.

A cross over only makes sense on a car that's getting a full-length system already - which rules out a track-only car. If it has a full length system and you want it turned up to 11 (as far as volume) then don't use a cross over. If you don't care how loud or want quiet, and/or want to maximize low-end, then a cross over makes sense in most cases.
 
Phreakish said:
Except it's possible to muffle a high performance setup without major losses. Done wrong, a muffled setup will lose you big, done right it should have little to zero impact.

Doing it right is tough though without having all the data on-hand necessary to engineer it properly and there's no one-size-fits-all approach because the right system for a 350hp 318 is different than the right system for a fire breathing 408, and using one on the other will likely have drawbacks in both cases.

A cross over only makes sense on a car that's getting a full-length system already - which rules out a track-only car. If it has a full length system and you want it turned up to 11 (as far as volume) then don't use a cross over. If you don't care how loud or want quiet, and/or want to maximize low-end, then a cross over makes sense in most cases.
Click to expand...

I agree with all this except that all street cars run full length exhaust. I have not run a full exhaust on my street toys since 1981.

If you are not required by law I see no use for it.
 
The part that is getting lost here also is what RPM range do you use most? All these NASCAR and open header examples don't really mean squat for guys wanting street performance. Street or all out drag only it still depends on what you have. I run 452 CID through fenderwell Hooker competition series headers with 18" 3.5" collectors. Those in turn connect to 3" pipe with an X and 3" in and out flow masters that turn down at the axle. Advantage exhaust on the 1/8th mile with the exception of the fact it marginalizes my poor suspension.
 
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