Is this truly a scienitific phenomenon, or is does it really increase flow and HP? I use an H pipe, and thats fine I think. My friend has an X pipe on his stang, and admittably so, looks pretty sweet.

 

From what I've gathered it's a lot better than an H pipe, because it doesn't have the sharp bends of the H pipe. However, for 3 times the price, I'm goin with an H pipe.

The reason for them working, I believe is, since you have 2 cylinders firing after each other on the same side, the exhaust gases struggle against each other in one pipe, so by connecting the 2 it helps the flow out.

 

Very interesting. Thanks Mark.

 

Yeah, they, work, but like Mark said, they're friggin expensive. And they don't work THAT much better, I'd go with an Xpipe if you can afford it, but an Hpipe will work.


Tim:rockon:

 

From what I've read, X-pipes are truly more for sound than power. At least in the mustang world, the power difference is almost negligable from all the reports I've seen. Some people like the sound better put personally I like the sound of an H more, not to mention like the smaller price.

 

My brother and I are going to build our own for his 76 Firebird dual exhaust. Its really that difficult. We might make a X-pipe + Y-pipe hybrid.

 

Cool idea I think, how exactly do you plan on doing that? I'm hopefully not coming across as a smartass by saying that, I'm just curious as to what you have in mind and why you think it'll be beneficial.

 

the theory behind an x-pipe is actually pretty simple.....

think of how a header uses its collector design to scavenge exhaust using the exhaust pulses....now make it bigger and put it between the 2 sides of the exhaust.....voila x-pipe...it just takes the collector concept a step further and applies to the whole engine not just one side....theoretically it could dramatically improve flow

 

In theory yes definately, but the way so many of them are made, the crossovers don't look ideal for good airflow at all, at least not to me. I guess mass production takes precendence over perfection most of the time.

 

true, a custom made x-pipe would always be better. also, the crossover should be located the same way as an h-pipe. place some paint on the exhaust and the point where it stops burning off is where you locate the X.

 

I think you would be better off for more power tuning your x-pipe placement to the placement of your collectors on your headers and also in placement to the tips of your exhuast to get max power from the sound pulses inside the exhuast

 

thats why you do that.....because that is the point the exhaust pulse is at its strongest and most defined....there is too much force for it to act effectively ahead of that point

 

we are talking about two different things here

what is going on over here is sound wave tuning.
that is determined on how long the piping is before it hits a spot of larger or smaller diam.

what it sounds like you are talking about is just a pressure escape
problems with that though include piping quality. pain quality. how think the pain was when applied.also the exhuast cools as it leaves exhuast port and blah lah blah... sorry I'm thinking about quite a few other things

 

when you do that you just use cheap *** paint....the only purpose is to find the point at which flame ceases to travel down the exhaust.....its at this spot where the exhaust starts to lose heat and pressure, and the pressure wave is at its most defined......and this is where the balance/scavenging of an x-pipe does the most good, and thats where you should put it. The sound wave tuning is cool if your looking for a specific exhaust note.....but pressure (exhaust) pulses are much more important as related to power

 

sound wave tuning IS for power not just making it sound better

that is why longer ppl vary how long there intake runners are, or why some ppl (granted few) vary how long the exhuast size is and the distance from the collector is from the exhuast ports

it works using the pos and neg pressure waves caused by sound

this way you can tune your exhuast to the powerband of your car rather then just picking a location and saying ok that's good

 

sonically tuning an intake runner perhaps, at least what it sounds like your talking about...involves finding the point at which the intake "resonates" which creates a sort of pseudo super charging effect at a certain RPM. while that is somewhat related to sound its more dependant on the frequency of the pressure waves that are incited by the design of the intake manifold....which are what causes the sonic waves in effect.

exhaust works much the same way....the sonic pulses in the exhaust really co-exist with the pressure waves. so they increase and decrease with each other over the same set of circumstances. Therefore, when you tune an exhaust to make maximum usage of the pressure waves (exhaust pulses) your doing the same for the sonic energy as well.

the effect a sound wave in and of itself has on an engine is negilgible because the vibration (much lower frequency, but still sound energy) has a much greater effect on the engine. The actual sound energy carried by the exhaust is just a by-product......it just happens to be a convenient tool for finding information regarding exhaust pulses. thats why it works.

 

HE HE HE

 

damn it I think we need to quit finding each others post

we always seem to get into some sort of "debate" as to how stuff works or what is better


hey never said the gains would be huge.... but I'm sure a gain could be found by such tuning.... two strokes are even more prone to such tuning but that is partly because of no exhuast port to keep the intake charge in there and huge amounts of overlap...

I would think almost anyplace you put the x-pipe is not going to make a huge *** difference but if I was to setup the x-pipe myself I would work to tune it to the powerband of the motor since I would think that it would make a bigger ( though maybe small) difference then just using the ol paint the exhust trick

 

see rx7 thats what i mean....i think we are both talking about the same thing in two totally different ways......you should absolutely have an exhaust that complements the powerband....but placing the x-pipe the way i was talking about does that. If you go to www.howstuffworks.com they have an excellent explanation of how an expansion chamber on a two-stroke works....and why the same principle absolutely doesnt apply to 4 strokes....its good readin:lala:

 

but the hot spot caused by the heat inside the exhuast might not be the same spot that would give you the best resonant frewqquency to give that small bump in power at the rpm range(s) you want

 

lol....it is though rx7....its a phenomena that just happens to always work. its like pez....you dont ask what its made of you just eat it

 

but it's too simple

and hey I want to know what pez is made out of

 

yes it is simple......and thats the way we like it. and no, i dont wanna know what its made of :rockon: