Supercharger?

[Black_Moons]

Hi, Has anyone seen a supercharger small enough to efficently mate with one of the 66cc chinagirls? Idealy belt/chain powered.. I have access to a full machine/welding shop so mods are not a big deal, Just wondering where I would even start to look for such a thing.
Roughly calculated that a 66cc engine at 8000rpm would only use 528 LPM of air (18CFM) if thats any help..

 

[BarelyAWake]

Because enough is never enough;

Engelbert Sczygiol designed supercharger for a 50cc two-stroke (1965)

Basic Principles in SuperCharging
GoKartGuru.com Blog Basic Principles in SuperCharging: A Go Kart With More Bolt On Power

Supercharged Honda 50
Supercharged Honda 50 Racing

elsberg-tuning (scroll down for example pics)
the bikes

More basic supercharger info, inc. examples & some reference to using a smog pump
supercharging

RC superchargers, viability unknown - said they could make a custom one for the 50cc displacement for about $600
RB Innovations is the world's premier supplier of radio control model upgrades and accessories. Catering to extreme R/C modelers and is widely known for its professional, premium service

Small Engine Turbocharger VZ21 - still prob too large for our application (min about 125-200cc)
MBE Motorsports inc. : Small Engine Turbocharger VZ21 [VZ21Turbo] - $349.89USD

Turbocharged Piston Engines Basic Info
TURBOKART

After quite a bit of research in my idle time, I came to the conclusion that while possible - it's simply not cost or labor effective as our China Girls aren't the best motors for this sort of performance upgrade for a couple of reasons - first & foremost is the inherent difficulty in "charging" any two stroke, the fact they're (the HTs) are so inefficient to begin with, and the probability that if successfully 'charged - the construction of the engine and the components couldn't handle it and it'd most likely grenade

...but hey, defo check it out - experimentation being the mother of all invention and alla that lolz

 

[Clotho]

The question of forced induction whether turbocharged or supercharged seems to come up about every 6 months. This subject has been dealt with several times. You may want to look up some of the older threads that discuss the difficulties of applying forced induction to one of these Chinese 2 strokes.

I will leave you with one question. The motor in question has no valves. How do you plan on achieving a boost condition?

 

[Black_Moons]

Barleyawake: Thanks for the info. Intresting list.
Clotho: Of course it has valves. The piston+ports = valves.

I really don't get how people don't think supercharging would help. Its a simple matter of making the input air more dense. Extra mods will likey help as well but it should still work.

 

[Clotho]

You don't seem to be following.

It is a piston ported engine but it doesn't have anything that resembles a valve.

Take a look at the cylinder and you will notice that on the Chinese engines the transfer ports overlap the exhaust port which is open to atmosphere. As the piston rises the transfer ports close first and the exhaust port closes second. This means that any boost you create will flow through the transfer ports and straight out the exhaust.

 

[Black_Moons]

Clotho: OK but a 2 stroke blows fuel/air out the exhaust anyway and they still run. Expansion pipes stuff a little back in. More crankcase pressure = hopefuly a little more then 'normal' gets into the cylinder, And hopefuly a little less then all of it is lost out the exhaust (Basicly guarenteed that more in won't ALL escape, even if most of it might. Might need more exhaust backpressure to help.)

 

[Crazy Horse]

I'm following this thread very interesting discussion going on here!

Peace Crazy Horse.
P.S. You Can Do It !!!

 

[Goat Herder]

This topic is always fun...

 

[BarelyAWake]

Clotho, Black Moons - I suspect that you're both right, just different ends of the same question... not that if it's possible to 'charge - but is it worth it?

The snag is diminishing returns, can you provide boost enough to overcome the loss in providing it? With the very simplistic HT engines, prolly not. Even if you managed a pressurized state - you'd loose so much, charge through the ports & power making it that you'd end up with a loss. TBH if I were to try 'charging any engine I'd start with a platform better suited even if a two stroke for their raw power to weight advantage - it'd just have to be of better construction if nothing else. I love the HTs don't get me wrong, but there's issues even with high compression mods (bearings, crank failures etc.), let alone a boost condition.

I started looking into small four strokes w/the thought of supercharging on my mind, turbos wern't to be ignored tho I prefer the benefits of supercharging. The more I looked into it, the more questions came up instead of the answers I was looking for - the one constant being ofc "diminishing returns", that the 50cc displacement range was woefully problematic, and very, very few folks had any success.

I'm not sayin' it's impossible ofc - but is it worth it? I've no idea - not being an inventor I decided to set that 'un aside for others to deal with and went another route

 

[LandSpeedRecord]

I saw a video, on vimeo I think. Turbo 2 stroke building strong boost, it had a very large and short expansion chamber with an extremely short trailing cone. It seems they were able to achieve a very strong echo from the chamber to force the boost to stay in the cylinder. Probably a very narrow and peaky powerband but it worked. I need to find it again it was pretty interesting.

 

[Slogger]

I had a silly idea, how about a tiny supercharger geared to the pedal cranks..
You want to get some boost you pedal like mad, and Varrroooom!
hahaha

 

[GoreWound]

for the amount of effort needed to get a 2-stroke making and using boost, would it not be better to start with a small 4-stroke like a Robin or a Huasheng, maybe even a proper 50cc honda pitbike motor if you can find one.
I would assume an engine like that would cope better with such a set up (maybe I'm wrong) and with the costs involved in putting it together I would rather do with a motor that wouldn't explode.

that said, lets say you either had a custom casting cylinder with a magic port map that lets you pressurise the intake, or an external valve set on your engine: what you will have gained is less that what you would gain from having the same amount of effort and custom work into making a 2-stroke engine just be better. if I have to make a custom jug with a custom port map, why not just make that jug out of stupendously solid alloy with massive intake and exhaust ports instead?
if I could do that i could easily make a custom head to go with it, dual plugs and massive compression.

**** at that point what would be stopping me from custom casting a bottom end as well?
if someone does decide to pull a series of stunts like that and make a china-girl copy of astounding build quality it would likely have comprable perfomance N/A to those KTM50 clones you see.

at that point giving it a turbo starts making some sense. as a bolt on to a stock kit engine? you have a recipe for woe.
if you did manage to do it though... AWESOME!

 

[bowljoman]

An IGH jackshaft can literally double the stock speed potential of a small engine. Virtually every ounce is dedicated to spinning, and generates almost zero heat. You can use your shop to fab up a 89$ shifter by Friday and with your 66cc @ 8000 RPM in third gear would be hitting 50's. Biggest bang for the buck is in the tranny. Worry about expansion pipes once you max out third gear. YOu wont remember or care about boost. guaranteed!