Reed Valve or boost bottle help

Discussion in 'General Questions' started by Justinsavs, Apr 19, 2016.

  1. Justinsavs

    Justinsavs New Member

  2. Hello Moto!

    Hello Moto! Active Member

    Unless you can modify an offset intake you pretty much answered your question. Anything is possible with the proper tools!
  3. 45u

    45u Active Member

    All boost bottles do is look good other then that they are worthless no matter what you do to the motor. I know this form racing RC cars and from experince.
  4. Frankfort MB's

    Frankfort MB's Well-Known Member

    If you run the stock intake and port match with minor porting it will run better than the reed or the boost bottle
  5. Steve Best

    Steve Best Well-Known Member

    I have to disagree with some of these comments.

    I found port matching the stock intake gave me worse power.
    You can try it yourself, but keep a spare stock intake to go back to.

    Boost bottles are a tuning tool.
    They are a resonator that has to be tuned just like an exhaust pipe, only the manufacturers have not gone that far.
    The small hose alone pretty much makes them useless.
    Hose diameter (bigger is better), length and bottle volume have to be tuned for a resonant effect.
    Better to get the basics working before messing with boost bottles, especially ineffective ones with long skinny hoses.

    Widening the top of the exhaust port helped torque, as did port matching the exhaust pipe.

    Last edited: Apr 20, 2016
  6. Frankfort MB's

    Frankfort MB's Well-Known Member

    I've port matched and it helped significantly, if your not running port matched gaskets then your not helping with anything it's just making the hole bigger but the gasket would restrict it
  7. Frankfort MB's

    Frankfort MB's Well-Known Member

    Boost bottles do not work well for these tiny engines while reeds help better with smoothness they don't provide much of a power upgrade if you don't believe me then check all the pros opinions and they will tell you that boost bottles just lighten your wallet to make you go faster
    45u likes this.
  8. Steve Best

    Steve Best Well-Known Member

    Not only that, Donald Trump is leading in the polls!
    Popularity gives some people a good feeling but it is hardly a measure of technical worth.

    Effortless opinion and words are worthless. Study the theory and experiment without prejudice. Share truth.

  9. Fabian

    Fabian Well-Known Member

    Reed valve = yes and lots of positives
    Boost bottle = waste of money and time, and zero benefit.
  10. 45u

    45u Active Member

    I agree boost bottle is a waste of time and money! I tried one on many of my radio control 1/5 scale in motors up to 32cc if anything it hurt performance. Talk to any seasoned large scale driver.
  11. Steve Best

    Steve Best Well-Known Member

    Finally some picts and some testing.
    Port matched and stock intakes: Which works better?

    I know, I know the "port matched" intake is not perfect but it is about 4mm wider than the stock on at top.
    The stocker worked better all around. More torque and more speed, less sputter of fuel into the air filter.
    Top speed dropped from 58kph (today) to 54kph (today). Reason? Reverse pulse is the theory.

    Since the port matched intake was now a waste, I decided to use it for a boost bottle test, since in theory the boost bottle overcomes the reverse pulse.
    Drilled and JB Welded a 1/2" copper branch into the intake. JB Weld did not hold, later soldered it.
    Silver 95% no lead solder worked well soldering the copper to the steel once cleaned up and fluxed.

    So this is what I ended up with. Notice the other end plug of the clear tube is a plunger.
    This allows me to play with the volume of the tube to "tune" it to the right resonance.

    Top speed of 54kph base line test with the intake plugged and weak on the hills. (stock was 58kph)

    So how did it work?
    As I tried different positions I got from 48kph to 62kph.
    You'd think I'd like the 62kph but it came with a loss of low end torque.
    Some positions made tractor like torque but lost top speed.
    Possibilities for tuning here. Need to graph results. This was just a quick trial.