## supercharger function

yes, i&#8217;ve seen the video of the supercharger on the moped, and thats the one i&#8217;m talking about. it sounds good, but notice it just appears to be a simple cylinder that is connected to the carb itsself. there doesn&#8217;t appear to be any type of charge tube, or venturi chamber that due to the shaping increases the speed of the intake air past the point than it would normally get if it were just sucking in air on its own. think of a venturi like this

_chamber |

expulsion&#8212;-< <&#8212;-<&#8212;-air -+&#8212;propulsion

&#8212;chamber |

any gas or liquid going from a greater area amount, funneled through to a smaller amount will speed up the expulsion of said gas or liquid to an exponential amount. this rush of air is the only way to FORCE more air than what is used inside of a combustion chamber.

definition: The fluid velocity must increase through the constriction to satisfy the equation of continuity, while its pressure must decrease due to conservation of energy: the gain in kinetic energy is supplied by a drop in pressure or a pressure gradient force. The effect is named after Giovanni Battista Venturi

now, the cylinder style used in that video won&#8217;t work as effective as it looks or sounds, because it is a simple cylinder, with a turbine connected at the end. it takes engine work to turn that belt, and the power gain from the turbine doesn&#8217;t appear to out weight the power loss from the engine output.

engines work by creating compression on the down stroke of the piston. turbines aid in make more effictive use of piston stroke, allowing pressure to be created on both the up and down stroke of the piston, but this also requires work, but in a larger displacement engine, there is a LARGER cc gradiant of run off that allows the turbine to spin at a speed fast enough to see a gain of power over work ratio. this small turbine doesn&#8217;t appear to accomplish this task

i will repost this in a new topic on supercharger defined

## Re: supercharger function

so ur point about the green supercharged moped basically is??

-Samz

## Re: supercharger function

i don't think it puts out enough power to compensate from the work the engine has to loose to make it spend. in other words. if it's up against something tuned without it, it'd probably loose

## Re: supercharger function

well first thing is how did he get the puey to turn , did he thread it in on the crank or something?

## Re: supercharger function

ok, see the teeth on the belt? they will grab to anything spinning, so he probably created a pulley wheel on the flywheel by adding tiny lips to it, setting the belt between them, and then cutting a slit out of the flywheel cover, then this belt is on a smaller pulley attached to the turbine attached to the back of the carb. it's a good idea, but the flaw comes in at the charge tube itsself. the shape of it is all wrong for what its trying to do

## Re: supercharger function

i emailed the person who posted the video asking for another video and more pics if possible.

-Samz

got imagine it was dont here, it would be the talk of the site.

## Re: supercharger function

i am not going to reveal how i would build one, because i plan on making one myself..but it's a good concept, just needs a little more work

no

nope

## Re: supercharger function

what do you mean nope? i know what i'm talking about

## Re: supercharger function

how is the shape of the tube wrong, its big to for flow that leads into a smaller port to compress the air before the cumbustion chamber. it could probibly be funneled more and matched up with the port better but the basic concept is good. still the only problem is how to keep all that extra air in the combustion chamber without going straight out the exhaust port, maybe reshape the intake port so its a little higher then the exhaust.

## Re: supercharger function

exactly my point. thats why i said i don't think it is designed correctly. the tube needs to have it's own small channel in the middle of it to funnel the air through, before it gets to the carb. like the tube shown here

## Re: supercharger function

DAMMIT! dictionary definition!!!!!!! :superchargers operate in the same fashion as a turbo; however, the energy to spin the compressor is taken from the rotating output energy of the engine's crankshaft as opposed to exhaust gas. THAT is not spun by exaust gas!!!! it would have to be mounted to the fucking exhaust port in order to be called a turbo

## Re: supercharger function

its a 2 stroke the primary compression ratio would limit the usable boost because you have to compress the crankcase first then send it to the combustion chamber. it has been tried and not worked so good.

two stroke has been around for over 100 years, supercharging has been around for 80 years, turbo for 60 years, why do they kit engines to be bigger when they could just turbo or supercharge?

## Re: supercharger function

I think thats kinda obvious Wari, they 'kit' because a couple hunks of cast and machined metal are way cheaper than building a whole supercharger... the supercharger could work, but it would have to be designed with a compensated expansion chamber. the 50cc kriedler streamliner was a rotary valve with a centrifugal supercharger. that would be the ideal setup 'cause the supercharger wouldnt have any drag until it got up into its effective rpm range. supercharging the case pressure would be totally kickass, but it would require the whole engine to be designed around the supercharger to really get the most out of it. i dont think putting a leaf blower on a stock puch would be worth much.

## Re: supercharger function

wow 140MPH!

"50cc kriedler streamliner":http://www.kreidler.nl/forum/speed-cw.php

## Re: supercharger function

Is this supercharger clutched so it only kicks in at a certain pint in the power band? Wide open throttle for instance at a given RPM? With either a supercharger or a turbocharger there is a trade off, one robs mechanical power from the engine, the other causes backpressure in the exhaust. I couldn't see the point in putting either on a moped due to the expense, besides that all that it takes to beat a supercharged engine is a bigger engine, which costs less.

## Re: supercharger function

Ouch my head hurts. Too much knowledge, not enough memory. oh the pain.

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