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Old 05-24-2011, 06:36 PM
escout's Avatar
escout escout is offline
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Join Date: May 2011
Location: Wyoming
Posts: 14
Default Re: Anyone out there with a "BoosBottle Industries" Expansion Chamber??

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Old 05-25-2011, 09:11 AM
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halfevil333 halfevil333 is offline
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Join Date: May 2010
Location: florida, USA
Posts: 307
Default Re: Anyone out there with a "BoosBottle Industries" Expansion Chamber??

Originally Posted by sputterputtBAM View Post
Loooks like it could be made to function. But not with my money, not for that price , not when good rep. SBP has a good alternative. If I wanted to save a buck I'd accept the modest gain and required re-engineering of a pocket bike pipe. (thats where I'm at now)
They(Boost) want $75 for that now!!!
should've put yer hard earned cash into making it work, instead of expecting instant bolt-on gratification...doesnt look much diff' than the pirates "happy pipe" 'cept they had properly welded and bent pipe instead of flexy- which you could've had an exhaust or motorcycle shop in your area do....

I know everyone out there LOVES the SBP kit, but I.m.h.o.- I think they are ugly as ****! and welcome any and all alternatives w/more aesthetic pleasantries!
...just remember to use pocketbike pipes which are stated to be FOR THE SAME CC/DISPLACEMENT RANGE AS THE ENGINE YER GONNA STRAP IT TO!!!!!
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Old 05-25-2011, 09:36 AM
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BarelyAWake BarelyAWake is offline
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Join Date: Jul 2009
Location: Maine
Posts: 7,212
Default Re: Anyone out there with a "BoosBottle Industries" Expansion Chamber??

There's far more than aesthetics to be considered with an expansion chamber, everything about exhaust system is important, not least of which is the headpipe diameter and length... which the above product doesn't seem to consider at all.

Originally Posted by Junster View Post
Remember how the pipe works. The exhaust sound wave expands down the front taper then hits the rear taper (which is usually at double the angle of the front) reflecting the wave back at the header tube. The idea is to get the header length "tuned" to have the wave hit the exhaust port just before the piston closes it. Stuffing some of the energy back into the port along with some of the exhaust gases as the piston goes up. The faster the engine is spinning (or the shorter the piston stroke is) the shorter the header needs to be to deliver the charge at the right time. To long a header and it's late, to short and it's early. A little long and you get a broader band. As they get shorter the rpm range is more sensitive but the pipe adds more to the HP. It's a balancing act.
some links;
A two-stroke

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boost bottle, cheap exhaust, expansion chamber

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