expansion chamber

[Crobo]

After doing some research ive decided that i want to upgrade my HT 2 stroke with an expansion chamber. I know there are a few available, but my roommate has a welder and i feel like the math is rather simple to figure out how to make my own. i figure that with a modified stock exhaust would be a pretty large and cheap upgrade.

Doe anyone have any insight into the math behind the exp chamber? is is very precise? basically can 2 guys in a garage with a college education figure it out?

Thanks,
Crobo

 

[motorpsycho]

"can 2 guys in a garage with a college education figure it out?"
possibly, but you need to have fabrication skills, general mechanical knowledge, and the basic knowledge of how a 2 stroke engine works, and how an expansion chamber works.
there are a lot of precise measurments, tubing diameters, tubing lengths, and stuff.
unless you know those measures, diameters and lengths and precisely where each one of them needs to be, it would be difficult to build one, especially using a stock pipe as a donor. it's not just about having a large diameter pipe...it's all in the way the pipe is tuned and the length that gives an expansion chamber it's performance.
There may be plans or blueprints available for you to use, but that's not guranteeing you that you will have an effective pipe when finished.
just my non-college educated opinion

 

[Crobo]

Didn't mean the college thing to be condescending, sorry if it came off that way.

i know the basic idea behind the exp. chamber (soundwaves, air flow etc) but i dont know the engineering behind it. Eh ~80 bucks isnt bad for someone to do the R&D for me. ive seen the SBP pipes and ifrom what i understand they are best, any comments on this?

 

[gothicguy64]

why build ? buy from pirate cycles there combustion chamber exhaust

 

[motorpsycho]

Didn't mean the college thing to be condescending, sorry if it came off that way.

i know the basic idea behind the exp. chamber (soundwaves, air flow etc) but i dont know the engineering behind it. Eh ~80 bucks isnt bad for someone to do the R&D for me. ive seen the SBP pipes and ifrom what i understand they are best, any comments on this?

no, no i didn't take it as being condescending at all...i understand what you meant.
I was just being sarcastic
That's just the way i am sometimes....no foul on your part at all.

 

[danlandberg]

So thats what it is ''sarasim'' M-PSYCHO. LOL

 

[danlandberg]

Crobo: There are chamber design/calculators on the net where you punch in specs (bore, stroke, port timing ect.) And it tells cone sizes and lengths depending on where you want your power band at. I got a chamber from SBP and am having a hard time fitting it any where on this BB D.I.Y. kit! (micargi M50 bike & Flying Horse 66/80 engine) I have already spent and arm & a leg on part mods ( angle head, larger front mount, ''speed'' carb & billet straight intake manifold) just to get the engine to work right in this bike! & still need to get a roller set up for the clutch & a bolt to plug the hole where the clutch riser used to be. Then I won't be able to ride it! (with only one arm & leg left!)

 

[danlandberg]

Crobo see if these links work www://en.wikipedia.org/wiki/expansion_chamber or www. buildandclick.com or www.members.bellatlantic.net Hope I got the link addresses right. but if not, just punch in two stroke expansion chamber calculations. And it pop up a bunch of different places.

 

[danlandberg]

I have a SBP chamber exhaust & it does not fit the BB D.I.Y. kit. (26'' + 66/80cc Flying Horse engine). I think the SBP pipe is nice in construction And would do a GREAT deal for performance! It just will not fit the MICARGI frame (up or down pipe installation). But eyeballing the stock pipe next to the chamber part of the SBP chamber I think I can get it to work, with out interfearing with peddles, legs, cables or rear tire & chain. (as a down pipe) With out going to the plumbing store for more copper tubing to get a better possibility of making it fit. Has any one used the stock header pipe & chamber section together? I know I.D diameters are different, & and it would be difficult to tune. But once fitted it would most likely still be better than the stock muffler.