How does a Boost Bottle work?

Frankenstein

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Jun 24, 2016
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Extending the length of the intake will cause atmospheric pressure loss on two stroke and ramp up turbulence. On a 4 stroke you can do this when you have valves open and pressure controlled by force created by the piston..
Take some advice from somebody who figured it out 4 years ago.

Oops, didn't notice how old this thread was!
 


D

Dizmo

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These guys got a 2 mph increase in top end by adding one. But, on the other hand, I get their top speed + 1mph - stock. And I weigh 250lbs...
I have one on order - I'll install and report.
 

Frankenstein

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Jun 24, 2016
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5,078
These guys got a 2 mph increase in top end by adding one. But, on the other hand, I get their top speed + 1mph - stock. And I weigh 250lbs...
I have one on order - I'll install and report.
Probably highly coincidental or just a nice extra dose of oxygen in the form of a tiny leak, boost bottles don't even work on the top end..
 

Captainkirk44

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Jun 29, 2019
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I just spent $30 on a boost bottle, and it did nothing for my bike but it sure looks nice. A total waste of money. My high compression head, my better carburetor, and my expansion chamber each separately made a noticeable difference. But this boost bottle absolutely positively did nothing. It was a total waste of $30. I can't believe I read so much about how they increase performance or power. If your boost bottle does anything for your bike then you have a carburetor issue or a vacuum leak. Out of all the things I've ever purchased for my two stroke bicycle the boost bottle takes the cake for a total waste of money. I can't believe I haven't read more on what a farce it boost bottled is. Don't waste your money like I did unless you like how it looks. And I'm not that thrilled about having extra stuff on my bike that does nothing. In fact I think I'll remove it because I don't want anyone that knows anything about two stroke bicycle engines to see it on my bike and then assume then I'm a dipstick that thinks that works. Because it does not work it does nothing.
 

JerboaJohn

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Jul 29, 2018
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ya, expensive bling only. theoretically, a bottle could work for a given psi and specific rpm related to its volume. From whst i gather about dirtbike tech, the airbox volume is tuned to reverberate with intake pulses much like an acoustic guitar. but it's less than a 2% effect on output.
just a gimmick vendors try to sell, hoping on the placebo effect
 

HeadSmess

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May 17, 2010
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3,033
like it was pointed out before... most high performance two smokers (and even 4t!) have boost bottles, but... they are made and tuned specifically. not an old soda siphon cartridge on a 6mm hose.

as always... dont buy bling... make things! experiment with pvc pipe and stuff! and remove the exhaust when testing intake mods...
 

JerboaJohn

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Jul 29, 2018
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pretty technical. i should look up the link to the formula for volume for X rpm @ n psi. I think it'd be worth to note,
but generally, there is no practical gain on a China girl. we've been thru this
 
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