superchargers on boats

[not2bright]

has anyone thought of putting a supercharger on a boat or am i the only one i bet you could get alot of performance gain out of it i thought of just having an impeller in after the carb. just a thought :

Joel Hanson

 

[Ron Olson]

I don't know if it is legal for racing or else someone probably would have done it by now. OS has one for a plane motor and I've seen something that looks like a blower on the MHz site in Germany. There might be some other problems also with possibly rods, glow plugs or something else.

 

[lohring]

Supercharged model four-strokes have been made by YS for years. They aren't racing engines, but have managed to hold their own against two-strokes in model airplane pattern competition even without favorable displacement restrictions.

In two-strokes turbocharging could work really well if scaling problems for the tiny torbochargers can be resolved. In fact, you can think of a tuned pipe as a no moving parts turbocharger.

Lohring Miller

 

[not2bright]

turbochargers wont work because two strokes dont have enough back preasure but a supercharger works off of the crank. there is nothing to do with the exhaust so you run a strong pipe on it i dont know its confusing to explain ???

 

[Mad Max]

Turbos,and superchargers are not legal for racing.

 

[Ian Inverarity]

Here in Australia there are no rules against supercharging. However with normal two strokes there is a servere limitation: the exhaust port is still open after transfer ports close! : That makes it very difficult to build up any significant boost pressure in the cylinder (it just goes out the exhaust!).

A uniflow two stroke design uses cylinder ports and poppet type valves in the head to allow it to run reasonable quantities of boost, but I have only heard of this style of engine as a diesel.

Ian.

 

[lohring]

You are all missing the point. Two-strokes, unlike four-strokes, are not hurt by back pressure on the exhaust. The piston does not need to push against the high pressure exhaust for a full upward stroke. To supercharge a two-stroke you need to raise both the intake pressure and the exhaust back pressure. This raises the cylinder pressure and increases power. The intake pressure only needs to be enough higher than the exhaust pressure to scavenge the cylinder.

A tuned pipe accomplishes this with acoustic waves. It is limited to boost pressures of about 1 atmosphere. A turbo charger can do better, but is limited by poor efficiencies in small sizes.

Lohring Miller

 

[not2bright]

the old jimmies were 2 stroke diesel engines and they had a supercharger i still think it is possible to put one on the only think i can think of that would make it not work is if it starts blowing plugs

 

[Mal_Mckee]

Forget SPGR. enk, Does anyone have info. on N.O.S.?

 

[Propjockey]

Don't know what the effects of introducing Nitrous Oxide into a Nitromethane fueled two stroke engine would be, but I think the weight and complexity of tanks, valves, induction and activation systems would pretty much rule out it's use for our purposes. Maybe it would be possible in a bigger, gasoline powered boat.

BTW--blown street rods use lower than normal compression ratios--somewhere in the neighborhood of 8-9 to 1.