Forced induction on a 49cc engine.

[FincH]

Probably one for the techies this but here it goes:

Following from seeing a turbo lawnmower, it got me thinking what else could be turboed.

I've seen you can pick up 49cc engines from mini motos for cheap on ebay. Would it be possible/worthwhile to either supercharge or turbo charge one of these engines?

Basicaly we want an engine for a homemade go-kart/soapbox type thing and the idea of it being petrol powered seemed cool.

I'm thinking the exhaust and inlet system on the 49cc will be a bit too small to mount a turbo though, let alone the engine be able to spool the thing up! We have a turbo from a Mk4 1.8 Golf T but seeing that it's the size of the engine, dunno if that'll work lol.

Also, how would a lawnmower engine be for use of power instead of the 49cc? I assume they rev quite low so perhaps not very good for top speed!?

Any ideas/suggestions?

Cheers.

[Smudger]

49cc engine wouldnt produce enough gases to spool even the smallest turbo (T2)

and not sure how high they rev either so could possibly not even get the turbines to move

[Dancliovalver]

install anti-lag

[stan]

The engine you are suggesting is two stroke. This gives arise to problems to to the actual function of the engine in terms of transfer ports, and how a 2 stroke engine uses pulse tuning as a major part of its operation via the scavenge effect they produce.

Basically unless you re-positioned the transfer ports in relation to TDC, you would get massive blow through...it would be much like turbocharging a car engine which is using high duration cam shafts.

If you are adament forced induction should be used, a 4 stroke lawnmower engine e.g Briggs & Stratton could be used. However, i dont think the mass throughput would sustain enough kinetic energy to produce boost at a usable pressure, even IF you found a turbo small enough.
I know of a bloke eho turbo'd a monkey bike...the results were poor.

That really only leaves a supercharger. chances of finding one small enough in this country are somewhere between slim and **** all, unfortunately. keep an eye on USA ebay for bike chargers. Again, ive seen a 125cc small bike supercharged, this worked, I think it made 30bhp as opposed to the standard 13bhp.

[Flan]

http://www.blmra.co.uk/

LOOK AT THE ENGINES THEY FIT

[FincH]

Wow thanks for the technical breakdown stan.

Hmm, as ever, seems it ain't as simple as just bolting crap on.

How about NoS on a two stroke?

Lol. I'd imagine it's going to be hard and exspensive to mount a 125cc supercharged bike engine to a home made go-kart :/

I did also hear of using a starter motor from summat like a Land Rover or Jag and connecting that up to some batterys with a speed controller. Meat to work!

Cheers.

[kj16v]

Er it's for a 150cc but ahh bless it's little actuator, aint it sweet!

http://cgi.ebay.co.uk/ws/eBayISAPI.d..._promot_widget

[u33db]

Looked at all this sort of thing when i had my scooter;

Its not worth it at the end of the day assuming you could find a turbo to fit.

If you're into small cc bikes then i'm sure you are well aware of bore up kits from the likes of mallosi which would be a better place, more fun and easier place to start from. They also do race cranks etc

Even sticking at 50cc most engines will take a substantial hike in rpm without any problems - e.g. my 2 stroke yam bw was limited to 10k but would safely got to 18/20k in stock form - this coupled with a larger carb (21mm or so), exhaust and cone will almost double the power.

Regardless though, theres no substute for cc....i don't know how much a mini moto engine goes for these days but i doubt its mega cheap. On the other hand you could pick up an old moto crosser (Kawa KMX/KX series would be good) with larger cc, more power etc for under a 100.

[u33db]

Wow thanks for the technical breakdown stan.

Hmm, as ever, seems it ain't as simple as just bolting crap on.

How about NoS on a two stroke?

Lol. I'd imagine it's going to be hard and exspensive to mount a 125cc supercharged bike engine to a home made go-kart :/

I did also hear of using a starter motor from summat like a Land Rover or Jag and connecting that up to some batterys with a speed controller. Meat to work!

Cheers.

Mini motos run NOS but not a lot and it will melt a standard piston. Again, higher rpm is the way forward.

How easy do you want the build to be? If its really easy go the automatic scooter engine route so theres no fannying about with gears etc...just an accelerator and brakes.

[FincH]

Thanks u33db!

Well on ebay seen a few 49cc engines complete for £60 inc delivery etc.

Deffo want it to be straight forward and simple, like power to an axle and yea simple brake and throttle set up.

Thanks for the knowledge ;)