X pipes

[Anonymous]

Here is a link with some x-pipe designs with PHOTOS:

http://www.v6mustangstuff.com/V8XPipe.htm

I think the design goal is to cross the pipes at the collector instead of putting the 4 pipes into 1 pipe.

My guess is that the length to the "X" adjusts the resonance of the primary pipe,

And the crossover allows the pipe to create a vacuum on the adjoining pipe much like the old Victorian perfume atomizers, which would draw the fluid up the tube because air was passed over the mouth opening. Much like carburators for that matter.

Lastly, I believe Cambell "tunes" his pipes (remember he keeps saying 8000 rpm) to create backpressure when he doesn't want the pipe to pull mixture out of the cylinder.

Evidently, there is some validity to his pipe design. - Dieter

[humhead]

Tony
I agree the theory is sound, but why not back it up with results? More improtantly why react the way he did to a simple request for information?
He's asking a potential customer to pay top dollar for an exhaust - and he won't even refund the entire purchase price if you're not satisfied.

He is a little arrogant... it appears to be out of ignorance and that he doesn't seem to have much empathy for others. Whatever hey?

Go back and read the delusional tirade I received in response to my question. That's more than a little arrogant - it's downright delusional.
Also note the nonsense regarding Edison & the light bulb. When confronted with the truth, he tried to pass it off as a joke. All I can say is stick to points & pipes Monty - comedy is not your strong suit!
My overall feeling about the whole thing is sadness. Dr. Campbell is an intelligent man. It's a shame he's also more than a little........ troubled

Terry
PS I did quite a lot of research on the patents he holds & the principles behind them. I still want to see a comparison test involving motorcycles.

[Anonymous]

Hi Humhead:

Yeah, for the record I agree with your post above.

I thought the Edison thing was strange. Someone that theoretical wouldn't understand that a bulb offers resistance to current, the filament gets hot and glows.

But I wonder if it is that simple. Things are as complicated as you want to look into is what I have found. The trick is to pick the top 3 or 5 or 10 as appropriate. Mr. Cambell has a way to go with salesmanship.

And then, not to honor your reasonable request for dyno results, then in my opinion I would just flat stay away from him and his product. It is VERY unusual that he would not have dyno results on his pipe...don't you think? He would WANT to know how superior his product is...as a technical person.

That doesn't mean his pipe doesn't have advantages over a 4 into 1. I'll bet it does, and he doesn't want to show the dyno because it will also show the weak points.

Something I have heard no one mention. The X-pipe design "crosses-over" pipes. We have all seen the Yoshimura "duplex" pipes with their cans welded to the down tubes. I betcha those cans are another form of what the X-pipe design does. The cans were designed to increase midrange. I believe they increased "effective volume" of the down tubes without seriously affecting flow and that they also created a vacuum on the adjacent pipe. Again, all of these affects occuring best at a certain RPM given pulse "phase" or simply frequency.

Believe me, I try to relate electronic theory to this stuff. They are quite similar. But it still is incredibly difficult. Some of the hardest science is laminar flow theory and behavior. That's pipes.

Most OEM's had a crossover before the mufflers. I have found this to increase midrange. I did it on a V-four. And I would bet that's what the Yosh cans did (and Suzuki did it on Katanas too!).

Buy a 4 into 1 system with the midrange cans on the down tubes, or learn about megaphone design and take a kerker header and put a properly designed, large volume megaphone on it. My suggestion. ...and thanks. - Dieter

[Mark Harrop]

You guys never cease to amaze me......

I just found this on e-bay and thought I'd run it by you guys for an appraisal, but it seems you are already on it.....

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4522603932&category=35596

more snake oil?....It looks cool though.....

[Anonymous]

more fuel for the fire...

Terry Vance in Gulfport Mississippi on the 1980-81 Suzuki With The 16 valve GS1100 Engine. Classic Terry Vance, narrow slot helmet, head turned and total concentration at the staging lights! Bike had Cone Head Carbs and a Murray "X" Pipe! Suzuki Twin Swirled The World, and 20 years later the heads still have the same Patent Number!

https://www.bertaut.com/gssuzuki.html

[Anonymous]

Update:

I reread the whole thread and looked at the latest posts.

I would say Monty was genuinely angry and sounds very frustrated that his pipe is not more well known, particularly that it has been since 1987 that he patented the idea.

My guess is also the bike does not need rejetting because the pipe creates backpressure when needed to prevent short-circuiting. I have learned jetting for a lean condition meant a pipe flowed better. It may not apply to this pipe.

I believe the pipe works.

Since Monty disputes dyno's, a fair question would be quarter mile times, changes in fuel efficiency in the bike. Terence?

[Anonymous]

Engines have torque and horsepower peaks. If you tune your pipe's "low pressure resonance" to coincide with the torque peak, you get best midrange. If you shift it higher, you sacrifice midrange but shift volumetric efficiency point a little higher up in the RPM range, so you get max horsepower. If you ever look at an engines horsepower or torque curves, the "area under the curve" stays pretty constant, you just shift it around.

Tony,

This is pretty much the crux of tuning. The area under the curves is mostly fixed and all you can do is optimize for your desired RPM range. I will not comment on the X-pipe design, since I have not read the site material, but your comments on it relating to it acting as a crossover tube sound like they are right on.

From what I have seen and read, the best pipe for peak power (and torque, of course) on an inline 4 is a 4-1 with a megaphone after the collector. Properly tuned, the 4-1 header produces the strongest scavenging pulses and a megaphone draws out the duration to the max possible time frame (when used with a reverse cone), resulting in the best power and widest powerband. This explains why the two most power intensive forms of racing, drag racing and F1 cars, still use a 4-1 megaphone design despite decades of research into alternatives. F1 in particular has pretty much unlimited budgets associated with it and they still use megaphones on their exhaust systems. Many of the current MotoGP bikes also run megs for the same reasons.

The disadvantage of the 4-1 is that it inherently creates a flat spot in the torque curve at about 1/2 the tuning RPM, which is why so many people swear at them. This can be worked around with careful pipe design, but it is always a difficulty to overcome. I have an aquaintance who has built many megaphone systems with great success and he uses quite a different approach than "typical" aftermarket systems. His systems use very short primary pipes to tune for a high peak RPM, then use a megaphone to fill in the low end and midrange. His results have been very good with this approach and the pipes do not exhibit the typical 4-1 flat spot at all. I am planning to build a custom 4-1 using his specs to see how well it works. From past performance I expect it to do very well. But you never know until you try...

For anyone interested in his specs (for my 82 GS1100E, stock valves and cams) they are:

Primary pipes - 25" long (including exhaust port length), 1.625"OD x 0.049" wall.
Collector outlet - 2.5"OD
Megaphone - 21-24" long (there is some leeway here), inlet 2.5"OD, outlet 5"OD if there is room. If no room, 4" OD outlet is OK.

Muffler to go after the meg section.

This tunes for a power peak at approximately 8000-8500rpm, which is what I requested as the stock redline is very conservative and can easily be extended to 10,000rpm. I also plan to run anti-reversion cones in the primary pipes to help eliminate the 4-1 flat spot. Sounds pretty radical, but going by his results with past work, I expect it to make significantly more power than my current pipe. We shall see. When I get it built, I will definitely be dynoing it, so results will be posted for all to see (one way or the other...)

Mark

[humhead]

Since Monty disputes dyno's, a fair question would be quarter mile times, changes in fuel efficiency in the bike. Terence?

Tony
Go back & read my second post on page two of this thread. I offered the use of one of my GS1000s as a test mule. I live near Englishtown NJ. I made that offer months ago. I haven't heard a word in reply. The ball is in Monty's court.

[Anonymous]

First response to Mark M's post. Thank you. I try to understand designs intuitively. Doesn't mean I am right, but my guess on the X-pipe function is an educated one.

Secondly, on the GS750EZ, the Kerker header primary tube lengths were about 31 inches. Peak Horsepower occurred at 8500 RPM. I eliminated the flat spot by jetting richer with faster taper needles and setting my cams as a compromise between peak HP and peak torque (106 to 108's) AND enlarging the exhaust canister volume (to about 26 " long by 5.5" in diameter-small by todays standards) AND keeping multiple baffles AND creating a scavenging effect at the exhaust tip and keeping the intake airbox. Not sure which change gave me the most. The large 4 in 1 pipe helped greatly.

To humheads last post: I hear you. Campbell is not replying. My guess, and it's a guess, is he's been down this road before and he sounds very frustrated in general..so no response. Won't get sales that way in any case. I would love to get some objective evidence on his design. Seems 1/4 mi times and fuel efficiency, roll-on times, before and after, on a stock bike would be excellent testimony to the superiority of the X-pipe. The first 2 are so easy to do, all you need is a stop watch, an odometer and a couple of tanks of gas. Roll ons are a little harder, but measurable.

Regards all. - Dieter

[Anonymous]

Secondly, on the GS750EZ, the Kerker header primary tube lengths were about 31 inches. Peak Horsepower occurred at 8500 RPM.

But your peak torque occurred at about 5500, right? That is really the point of max resonance and scavenging on your pipe.

I eliminated the flat spot by jetting richer with faster taper needles and setting my cams as a compromise between peak HP and peak torque (106 to 108's) AND enlarging the exhaust canister volume (to about 26 " long by 5.5" in diameter-small by todays standards) AND keeping multiple baffles AND creating a scavenging effect at the exhaust tip and keeping the intake airbox.

As you note, the cam lobe centers have a large effect on the shape of the torque curve. Timing those to match your pipe should produce the best power, but it may not be the right type or where you like. My goal with the new pipe is to "rock" the torque curve to higher rpm for more peak power. If I can keep the current bottom end and midrange torque and move the peak over about 1500-2000rpm it would be ideal. I would like around 118-120rwhp when all is said and done (this will eventually include port work, new cams and bigger carbs). The new pipe will have a lot more volume for a muffler than the current Kerker can has. I hope to find the same sort of gains as you mention. As I mentioned elsewhere, I am currently working on a new tail pipe to replace the Kerker one. The new tail pipe will have a true meg with reverse cone, followed by a small plenum chamber and a large core muffler section. It will have about 6 times the flow area and close to double the original volume after the header, all in the quest for more flow and scavenging.

Not sure which change gave me the most. The large 4 in 1 pipe helped greatly.

That's the bitch of doing all this experimentation. You really need to do one thing at a time, but who has that much time (and money)?


Mark

[first timer]

how about some drawing to better describe what you guys are talking about, simple things like showing what a revers cone in a mega phone looks like.

-ryan

[Anonymous]

how about some drawing to better describe what you guys are talking about, simple things like showing what a revers cone in a mega phone looks like.

Take a look at:

http://www.burnsstainless.com/Megaphones/megaphones.html

Actually, the Burns Stainless site is a great one to take a look at for a bunch of header/collector/exhaust info. Beautiful stuff, but lots of $$$.

Mark

[Anonymous]

The guy got awful defensive awful quick. The business about dynos is part true, part bull*@%^$*@%^$*@%^$*@%^$. A dyno is just a tool, it's not magic - the physical principles are not hard to understand, and dyno runs produce observable, repeatable numbers that allow comparison. And the ranting about stuff not found in physics textbooks definitely gives a rise to the old quack meter.

Then again, factory pipes for years and years used crossover-type designs, and when you replace them (like the ones on the GS', for example) with a 4:1, you get the flat spotting and the leanness at various rpm, just like he says, which can't always be tuned out completely.

So I'm confused - is the "X" supposed to offer more power overall, more top-end with a smoother bottom end, or what?

[Anonymous]

X-Factor

The cost of those x-pipes is UNBELIEVABLE - $580.00?!? A V&H system is under $200.00, and a custom-built 321 stainless system (also using an "X"- thingy) from Burnsstainless would cost around $1000.00 - $1500 including labor.

[Anonymous]

X pipe

I will let you guy's know if the pipe works, I have bid on one, I dont care about the power Iam buying one for the looks ( may sound stupid, but I can afford to be stupid cause I was smart when I was young witch allows me to be stupid with my money now) )