400ccStroker_shee Posted April 3, 2007 Report Share Posted April 3, 2007 i found this info while searching on the internet because I'm trying to learn how to do my own porting! Boost Bottle How does a Boost Bottle improve performance? Air rushes thru the carb on the intake cycle. Ignition accelerates the piston down, forcing the reeds to snap shut. The momentum (inertia) of the air has to go someplace. It goes back thru the carb causing a double rich mixture. The result can be rough idle or hesitation. Due to the high velocity of the fuel air mixture through the carb boot, we need to take advantage of this momentum/inertia energy. The Boost Bottle and tube provide storage for the fuel air mixture between carb boots. The energy (pulse) forces the pre-atomized mixture in the tube from the previous cycle into the adjoining carb boot where the reeds are just opening and ready to receive the fuel air mixture. The boost bottle and tube provide a "boost" supercharge effect to each cycle. The boost bottle is most effective at lower and mid-range rpm, and, when you are on & off the throttle. It assists in filling the cylinder (shorter distance) for a fraction of a second until the carburetor venturi gets enough velocity to fully atomize the fuel. The advantage is that it brings up the torque and horsepower in the bottom of the rpm range, up to where the pipe(s) starts to work. There is a small benefit at high rpm's. What Size? Singles = usually the CC of one cylinder or larger. 700cc Twins = 300cc boost bottle. 700cc Triples = 225cc. Variables: Engine CC's, Carb Size, RPM below pipe, Number of cylinders. Large carbs like larger bottles/tubes. Triples like smaller due to less time between pulses. I use the TSR computer software to calculate the Boost Bottle for a specific set up. Yes they work, when the size is right, the inertia of the air is stored like a spring in the boost bottle to help charge the next cycle. Try tuning a Yamaha Phazer without it's boost bottle! Power valve engines may not have similar performance gains because the valves will keep the bottom end crisp. Testing w/ powervalves will probably show gains off idle and low bottom end. Is it worth it?? That depends on what you are willing to pay for some torque and a couple of horses! -------------------------------------------------------------------------------- Quote Link to comment Share on other sites More sharing options...
cdubbz111 Posted April 4, 2007 Report Share Posted April 4, 2007 I hate to throw this off topic but what exhaust setup are you runnin on your black banshee? Quote Link to comment Share on other sites More sharing options...
yamaha04 Posted April 4, 2007 Report Share Posted April 4, 2007 I hate to throw this off topic but what exhaust setup are you runnin on your black banshee? looks like fmf fattys with polished power core 2 silencers Quote Link to comment Share on other sites More sharing options...
400ccStroker_shee Posted April 5, 2007 Author Report Share Posted April 5, 2007 looks like fmf fattys with polished power core 2 silencers he's right fatties with polished pc 2's Quote Link to comment Share on other sites More sharing options...
locogato11283 Posted April 5, 2007 Report Share Posted April 5, 2007 i didnt even read anything above. i just wanna say boost bottles suck! bye bye now. :biggrin: Quote Link to comment Share on other sites More sharing options...
!TWISTER! Posted April 5, 2007 Report Share Posted April 5, 2007 I'm trying to learn how to do my own porting! I can explain you step by step, the guy who wrote this wouldn't ever touch my banshee. I'm not a guru on engine building, but what he said is completly wrong. Quote Link to comment Share on other sites More sharing options...
RoostRocket Posted April 5, 2007 Report Share Posted April 5, 2007 weres your boost bottle? also i heard a green powerband gives the best bang for the buck!!! lol... Quote Link to comment Share on other sites More sharing options...
KHall Posted April 5, 2007 Report Share Posted April 5, 2007 weres your boost bottle? also i heard a green powerband gives the best bang for the buck!!! lol... Dang I thought the purple powerband was the best bang 4 the buck last time I listen to my 4 year old nephew Quote Link to comment Share on other sites More sharing options...
400ccStroker_shee Posted April 6, 2007 Author Report Share Posted April 6, 2007 Dang I thought the purple powerband was the best bang 4 the buck last time I listen to my 4 year old nephew you guys are stupid. I do use a boost bottle, I didnt really feel a hp increase but I didnt feel a decrease either and it looks better than the stock tube. I just put that info out there because some people like info like that to make their own decision weather they want a boost bottle or not. any there is always someone out there that has to make a stupid ass comment. I'm also pretty sure that they didnt design the boost bottle to hurt the performance. Quote Link to comment Share on other sites More sharing options...
HotCarl Posted April 6, 2007 Report Share Posted April 6, 2007 If it did something it would show on dyno sheets, which it doesn't. If you want to run it because it looks cool thats fine, but realize that it gets in the way of cables which rub on it can can cause the intake boots to tear. Quote Link to comment Share on other sites More sharing options...
majicmike Posted April 6, 2007 Report Share Posted April 6, 2007 I run mine with my amp link Quote Link to comment Share on other sites More sharing options...
Shee-Male Posted April 6, 2007 Report Share Posted April 6, 2007 I belive it was Tommy boy that said "anyone can shit in a box and mark it garunteed", boost bottles are just a gimmick, like splitfire sparkplugs, not to mention a HUGE waste of space, and the explination writtin above....truly the silliest thing I've ever heard. Quote Link to comment Share on other sites More sharing options...
FireHead Posted April 6, 2007 Report Share Posted April 6, 2007 any there is always someone out there that has to make a stupid ass comment. I'm also pretty sure that they didnt design the boost bottle to hurt the performance. It appears that you have taken it upon yourself to be the one to make the stupid ass comments. The boost bottle was developed to make money..................that's it. The laws of physics that are violated by the statements made in the first post in this thread are mind boggling. Quote Link to comment Share on other sites More sharing options...
ojcool Posted April 6, 2007 Report Share Posted April 6, 2007 (edited) Lets discuss this. I don't think the guys are trying to be smart asses, it's just that boost bottles are kind of a running joke. Lets talk about WHY this individuals statements are misguided. Boost Bottle How does a Boost Bottle improve performance? Air rushes thru the carb on the intake cycle. Ignition accelerates the piston down, forcing the reeds to snap shut. The momentum (inertia) of the air has to go someplace. It goes back thru the carb causing a double rich mixture. The result can be rough idle or hesitation. The flaw in this explaination is that if the reed is closed there is no air moving throught the venturi of the carb and therefore no vacume to pull additional fuel into the intake stream.. Therefore there would be no "double rich mixture". The air cannot move backwards back through the carb if the reed is closed. Now since the cylinders are 180 degrees out of phase when one reed is closed, the other is open preventing any type of pressure to build inside the boost bottle. Due to the high velocity of the fuel air mixture through the carb boot, we need to take advantage of this momentum/inertia energy. The Boost Bottle and tube provide storage for the fuel air mixture between carb boots. The energy (pulse) forces the pre-atomized mixture in the tube from the previous cycle into the adjoining carb boot where the reeds are just opening and ready to receive the fuel air mixture. The boost bottle and tube provide a "boost" supercharge effect to each cycle. The problem here is that the atmospheric pressure inside the intake tract, and the boost bottle would be equal therefore even with extra volume and the so called "inertia" the mean pressure would be static throughout and prevent any storage of energy in the additional volume. With that said the additional problem of the opposing cylinder having it's reed opening would prevent any pressure to build in the bottle anyway. Now, having a crossover tube (as is the stock configuration) does allow for the pressure deferential between the two intake tracts to be relieved and does provide some real benefits due to the ability of the cylinders to effectively "share" both carburetors. But this is a function of vacume, not boost. Additional volume does nothing to improve this effect especially if you are not increasing the size of the port on the intake boot itself. Edited April 6, 2007 by ojcool Quote Link to comment Share on other sites More sharing options...
David Keith Posted April 6, 2007 Report Share Posted April 6, 2007 (edited) If it did something it would show on dyno sheets, which it doesn't. If you want to run it because it looks cool thats fine, but realize that it gets in the way of cables which rub on it can can cause the intake boots to tear. That's right. When you take the time to research the "boost bottle", you'll find only "suggestive data" about performance increases. There is alot of "talk", not facts to back them. Edited April 6, 2007 by David Keith Quote Link to comment Share on other sites More sharing options...
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