[Climb]

:Thumbsup2: How Two-Stroke Expansion Chambers Work, and Why You Should Care. aper:



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[xX_Menace_Xx]

o.k so, why doesn't nasa strap sum t 5's to their space ships to give better rocket power? jkg...nice post climb! i learned something today.

 

[Morph0906]

should make it a sticky in the exhaust forum!

 

[Climb]

Did so too Morph, thanks for the suggestion! :Thumbsup2:



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[2strokefan]

Its amazing how our pipes play a HUGE part in the way that our rides perform. Most people don't realize that the charge enters back into the engine from the head pipe and exits again. And the speed that all this takes place is incredible. Thats where we get our "powerband" from.

 

[trx]

SHORTER head pipe makes more topend becouse of a stronger charge and faster return

LONGER head pipe like most 250r pipes make a more weaker charge but longer time making more torque

 

[kennedy_power]

:Thumbsup2: How Two-Stroke Expansion Chambers Work, and Why You Should Care. aper:

Have you backed that up on a dyno and track?

 

[radman3120]

Have you backed that up on a dyno and track?

lol yea i heard straight pipes were the way to go. someone should do a comparison

 

[radman3120]

Also, Climb, good stuff all the reading links you've been posting recently. I've read through some but still have a window full of tabs I have to find time to read now lol, not to mention everything else that spun off of it (grail engine, hcci, battery powered vehicles, an engine that switches between 4 and 2 stoke, etc)

 

[Morph0906]

Have you backed that up on a dyno and track?

Didnt know Climb was responsible to back it seeing as how he did not write the article. whats your point? Is the theory incorrect?. can you disprove any of the information in the article? can you prove any of it?..

 

[radman3120]

Didnt know Climb was responsible to back it seeing as how he did not write the article. whats your point? Is the theory incorrect?. can you disprove any of the information in the article? can you prove any of it?..

I didn't really understand the comment so I just figured it was a joke. It's not really an extensive article it basically just says we should use expansion chambers which we all do. kennedy, if it wasn't a joke, my bad. def fill us in, tho

 

[Climb]

Have you backed that up on a dyno and track?

No need for a Dyno run to understand performance pipes.
Dyno only, not a a track.. My machine is too slow for a drag strip, but I'll bust that ass thru the dunes all day long!



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[MrSweetleaf92]

Didnt know Climb was responsible to back it seeing as how he did not write the article. whats your point? Is the theory incorrect?. can you disprove any of the information in the article? can you prove any of it?..

Chuck Norris can!

 

[skipzero]

Always knew Mr Packard was a step ahead

 

[Bigdog302]

here is another great read by Gordon Jennings.very informative!
you will need Adobe Acrobat reader installed to view the page.Gordon Jennings was also the author of the two stroke tuners guide.
http://3cyl.com/mraxl/manuals/jennings/chambers.pdf

 

[bysior]

I have a question regarding the expansion chamber for a 3 cylinder engine – three into one - common chamber design. Obviously in this type of engine the cylinders are offset by 120 deg. and, as in any 2 stroke engine, the exhaust port of each cylinder is open typically for about 180 deg. This arrangement creates an overlap in the exhaust time of the adjacent cylinders. And here is my problem. The well known theory of the negative and positive pressure waves created by the chamber cones is explained and always applied to one cylinder only. In my case, with 3 into 1 exhaust manifold, the situation is not as simple as in the one cylinder engine. Exhaust ports are connected in the manifold and the overlap of timing causes pressure waves to interact with each other. Exactly when in a tuned single cylinder exhaust one would expect the returning wave to near the exhaust port just before it closes, in the 3 into 1 manifold the new pressure wave appears from the just open adjacent cylinder. And it looks to me that this new wave, because it is much stronger than the bounced one, will play the main role here. If what I think is right, what is the point of bothering with the “tuned length” of the chamber and having the baffle cone if the returning wave is overpowered by another one? Yet, we know that expansion chambers for 3 cyl. engines do exist and they seem to work.
Can anyone explain me what is wrong with my thinking here?

 

[HondaATC]

I have a question regarding the expansion chamber for a 3 cylinder engine – three into one - common chamber design. Obviously in this type of engine the cylinders are offset by 120 deg. and, as in any 2 stroke engine, the exhaust port of each cylinder is open typically for about 180 deg. This arrangement creates an overlap in the exhaust time of the adjacent cylinders. And here is my problem. The well known theory of the negative and positive pressure waves created by the chamber cones is explained and always applied to one cylinder only. In my case, with 3 into 1 exhaust manifold, the situation is not as simple as in the one cylinder engine. Exhaust ports are connected in the manifold and the overlap of timing causes pressure waves to interact with each other. Exactly when in a tuned single cylinder exhaust one would expect the returning wave to near the exhaust port just before it closes, in the 3 into 1 manifold the new pressure wave appears from the just open adjacent cylinder. And it looks to me that this new wave, because it is much stronger than the bounced one, will play the main role here. If what I think is right, what is the point of bothering with the “tuned length” of the chamber and having the baffle cone if the returning wave is overpowered by another one? Yet, we know that expansion chambers for 3 cyl. engines do exist and they seem to work.
Can anyone explain me what is wrong with my thinking here?

I thought the same thing in the past - but have read in a few places that basically there is some other formula to account for multiple cylinders into one pipe (don't ask me how, I have no idea, lol). It doesn't work as good as a single chamber for each cylinder, but there are ways and methods to construct them where they work the best. Most jet-ski's have only 1 chamber for 3 cylinders like my GP1300R, and it still makes 165hp...

 

[Jaguar57]

You can put holes in the baffle cone and then add another section of pipe to catch what comes out of the holes. That is what some karts have and it broadens the powerband. Or you can make the belly about 4 times as long as normal so the baffle wave only comes back to the cylinder at lower RPM.

To read an in depth explanation of expansion chambers go to www.dragonfly75.com/motorbike/ECtheory.html