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Do these work? (Boost Bottles)

Discussion in 'Scooters' at netrider.net.au started by mr_sikma, Jun 2, 2006.

  1. Hey,

    I found these on ebay...


    Do they actaully work?

    Simple to install?

  2. These systems work if they're correctly installed and sized to the engine capacity, and free of leaks.
    It's similar in operation to the expansion chambers you see on 2stroke engine exhausts, but the opposite in function.
  3. i have looked around a bit on the net and it seems that some bikes come standard with them.

    are they easy to install?

    will it work on my 50cc skoot?

    i need all the extra power i can get ;)
  4. Go look at Inci's Vespa750 post! :LOL: :p

    Power indeed!
  5. yeah thats crazy!

    but i mite need a liscence and ALOT of $$$

    these bottle looks cheap and easy, and hopefully effective!
  6. I've never installed one but from what I gather it's a fairly simple operation, if you are somewhat technically minded.

    I wouldnt expect noticeable gains from a 50cc engine, through if everything is installed correctly and leak free, you may notice a slight difference.

    There are many other avenues for upping the power on 50cc scooters, it just depends on your budget
  7. Well Yamaha certainly think so, they invented the concept and called it the 'YAMAHA ENERGY INDUCTION SYSTEM' (Y.E.I.S). It was standard on a number of Yammy 'Strokers' in the 80's and 90's like the RZ series.

    EDIT - The theory is that 2 stroke engines with reed valves 'spit back' a little of the fuel air mixture. Theoretically the boost bottle 'buffers' this in a tank with extra air. At the point that one chamber spits back this bit of mixture, the other is just starting its intake, so the boost bottle on one chamber can then pressurize the bottle on the other chamber. That's the claim anyway. I can't see how it would work with a single cylinder like your Bolwell though.
  8. okay thanks for all the replies.

    so it doesnt sound like it will suit my single piston 50cc?

    i mite email the seller and see what he says!?!
  9. He will probably recommend you purchase his product :wink:
  10. they say they are used on pocketbikes...

    the pocketbikes use a very similar 50cc set-up hay?
  11. How come?
  12. If you read my post above explaining how they work, it should be self evident, Quote,

    "The theory is that 2 stroke engines with reed valves 'spit back' a little of the fuel air mixture. Theoretically the boost bottle 'buffers' this in a tank with extra air. At the point that one chamber spits back this bit of mixture, the other is just starting its intake, so the boost bottle on one chamber can then pressurize the bottle on the other chamber."

    The simple answer is because to work at all, they require one cylinder to be charging one bottle (the correct term is 'resonator'), while the other resonator discharges. The sequence is then reversed. They are almost certainly a total waste of time as an aftermarket extra anyway, even if you have 2 cylinders. The most optimistic estimates from a factory designed and fitted resonator setup is 1 to 1.5% more power at one narrow spot in the power band. To achieve even this, the resonators must be perfectly tuned to that particular engine, both in volume and length. I spent many frustrating hours trying to improve on that measly 1 to 1.5% when I raced 250 proddy bikes, and trust me, it's a waste of time.
  13. They shouldn't. After all, that's the function of the reed valve. When a low pressure is caused in the crankcase as the piston moves towards TDC, and with the inlet port "open", the reed valve opens to let air/fuel in. As the crankcase pressurises with the piston falling to BDC, the reed valve closes and the air/fuel mixture is forced up into the combustion chamber (on top of the piston) via the transfer ports).

    Some two stroke pistons have holes or ports in their skirts where the air fuel mixture is drawn through directly to the crankcase.

    That bottle in the OP's photo looks suspiciously like that a mate set up on his postie bike. It was a nitrous oxide system with the bottle being the gas cylinder.

    If it's not that, exactly how does the system (pictured) work?

  14. I seriously doubt that it does. As I said, even YamaSusiZaki only ever claimed 1 to 1.5% on the factory built setups that were standard on all their 2-Stroke sportsbikes from the mid 80's. Personally I believe it was more marketing hype than anything of practical use.
  15. Ram tuning if intake length will have a far greater effect on intake charge than a silly little bottle wil. Search ram tuning on google and you wil see how that bottle will be useless.
    Perhaps you should buy one of those electric superchargers too.

    Regards, Andrew.
  16. If you seriously want to improve power output of a small capacity 2-stroke there is nothing that will come close in effectiveness to a well designed expansion chamber with a 'stinger' on the extreme end.
  17. It reminds me of a thing that I saw once. A guy designed and fitted an exp. chamber to a chainsaw. Power output was trebled, apparently.

    Probably also explains why Sea-doo and other PWC engines put out a heap more power than their outboard cousins. A PWC has a properly designed exhaust system for their two stroke engines, whereas an outboard, like a Mercury or Evinrude doesn't have the same power/capacity ratio.

    My Sea-doo was an 800cc triple, but punched out something like 130 hp. An Evinrude or Mercury 150 is typically a V6 2.5 litre engine.

    What I want is what a mate bought a coupla years back. A supercharged 4 cyl 4 stroke. Something like 180 hp propelling a craft that weighs probably a third of the average 15' half cab equiped with a similar output engine...
  18. Some race outboards would raise your eyebrows! Heavily modified, massive porting, tuned length intakes (trumpets stick out the cowls) and modified exhaust bells inside the leg. The Mercury V6 engines and earlier inline sixes can easily have output doubled and maintain reliability.
    Also interesting to note that serious outboard racers ditch oil onjection and run premix, they don't take chances on suspect oil injection.....
    If I had a two stroke I wanted to wake up, I'd look at the aforementioned expansion chambers and some good porting. Then you get into the issue of needing low end torque, which porting is no good for.....

    Regards, Andrew.
  19. A mate of mine was Number 1 in Aust racing PWC's (his name is Dave Ellis. He also came 6th in the IJSBA which is the unofficial world titles). He raced it the Pro-Modded 1200 catagory. His race boat put out over 230hp and did 0-100 in under 2 seconds on its way to a top speed of around 140kph.
  20. so something like this...