How Are These Pipes Made?

[Smoker]

More interesting custom pipes.

[Jeff B]

Is that three into one into two?

[lost1750GTV]

I've thought of doing that on an old 500 mx bike where current big silencers are just too bulky, and it can't breathe with a single small one.

[kenny]

Built by someone who knows nothing about 2 strokes

[silverstrom]

Built by someone who knows nothing about 2 strokes

+1

It looks pretty, but seems to be completely opposite to the correct function of two stroke pipes. Walter Kaaden is turning in his grave.

I encourage anyone who thinks that pipe is a good design to read some 2 stroke theory.

[Smoker]

Built by someone who knows nothing about 2 strokes

When I see an interesting pipe setup, I always have lots of questions. Most of which will go unanswered.

My first question is always the same. How much HP does that pipe setup make?

We all know the setup isn't optimal, but how much so? Would be cool to have a computer program where I could put in pipe/engine setups like this and get HP estimates. Does software like this exist?

Not looking for this kind of setup. Just interested in the dark science.

[silverstrom]

.

[Jeff B]

I've owned a snowmobile the came with a 2 into one exhaust pipe. It worked good. I am under the assumption that it would have had better peak HP with twin pipes. I have never seen a three cylinder sled with a single pipe. My gut feeling is that this bike "could" perform well at low to mid range rpm's and will probably perform poorly at high rpms. Assuming the stingers create the proper back pressure, I wouldn't expect them to be an issue.

[Smoker]

Well, I guess my point is that I can't accurately judge a pipe design by looking at it. When I ask, it seems that no one else can either. Usually, the only response I get is that the design is no good. But, my tiny brain can easily surmise that these crazy designs won't produce the HP of the typical racing-type expansion chamber that we all use.

There are many reasons to deviate from the typical expansion chamber design.

When Martin Aircraft Company started the development of their "Martin Jetpack" they needed an engine with at least 200hp at low rpm and at low weight. Clearly, maximum HP is not the goal. I think the goal is to get the most HP within the design parameters they want to use.



The subject of my curiosity hasn't changed. Very interested in how much HP these different pipe designs make, and why. Reading about expansion chamber theory is easy, but without actual numbers from dyno testing, it doesn't help much. I can't put down a pipe design, just because it's not a racing pipe.

[Jeff B]

I can't put down a pipe design, just because it's not a racing pipe.

I agree. That waterbuffalo doesn't look like it was built for any kind of racing application. The pipe may function well just bombing around town. Without understanding the builders goals I try not to judge the outcome. I know nothing about that jetpack engine, but I'd bet with an exhaust system like that, it has a very narrow powerband. In a bike that engine would probably be uncontrollable.

[Smoker]

Another 2 into 1 Banshee engine. Ducati S4 frame & swingarm are awesome.

[Smoker]

RZ500 crossover pipes. Pretty sure I've got several pics in my laptop. May be other crossover pics in this thread, too.

[Smoker]

THIS.







Hope you're taking a close look!

[Smoker]

The finished custom race bike.

[lost1750GTV]

Serious nice.