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OK,revkev6 got me thinking....

Kawasaki does a 1498cc supercharged 4 cylinder engine,260HP at 7700 rpm.

Yamaha does a 1812cc supercharged engine(couldn't find the hp specs).

Superchargers beef up the torque right?

And torque is more important for a street driven car right?

OK so how can I hook to a tranny for a fair price?

I don't know much about these watercraft. I think they have integral pumps, which would need to be removed, then an adapter made for a driveshaft. I hope the pump isn't under the motor...

Snowmobile engines have been used, they have a variable ratio transmission, which would be interesting. If you look on Youtube, you can find some technical videos on "Cup Light" cars, I think they were called. They ran something like 130 HP.

THe motors you mention sound interesting, but adaption will be a significant effort... A whole new direction for donor questions though

Which usually means very,very expensive

they have no transmission... there cams are built for water, not road. Meaning the engine is not built to support the wear and tear a car sees due to the friction between tires and the road. You launch a car and there is much more stress on the motor internals then when you launch a ski. The prop will just spin...

Ive worked on many 260+hp skis with everything from turbos to superchargers, inner coolers to watercoolers to no coolers... there simply built for the abuse on water, not land.

Snowmobile engines would work because they can see many of the same abuse situations that a car sees. Good thinking but in reality it wouldnt work.

while some of your concerns are valid, the durability of the engines isn't. Rotax 4tec engines are what is used in 4 stroke seadoo watercraft and skidoo snowmobiles. same engine. besides, marine engines are ALWAYS built stronger internally than their autmotive counterparts because while an automotive engine may spend the majority of it's time fluctuating between 2-3k rpm most marine engines will be set to cruise at a higher RPM 3-4k constant for autmotive based marine engines, higher for watercraft (although you don't generally cruise on a watercraft)

I would like to take a look at the output shaft on a watercraft engine. I'm sure a flywheel could be mounted to it.

I wonder what it's like driving on a track with one of those variable ratio setups like what they use on snowmobiles. Or on the street for that matter.

You would get automatic traction control and you would always be at ideal rpms, but seems like there would be a little lag while the engine speeds up after braking.

Your right about marine engines being tougher. I remember in the Ford SVo catalog, lots of the road racing stuff including heavy duty engine blocks where noted as "Not For Marine Use".

Are these 2-stokes? You could bolt a pair of them together at the crank outputs - sandwiching the drive sprocket or pulley. Run one of them backwards.

well, the CVT transmission idea would take alot of work. i ride snowmobiles as well. these new engines transmit so much power that sometimes you will have problems with belts lasting even on the sled.

heat is a big issue with the snowmobile clutches
there is nothing like traction control in a snowmobile CVT
powerband depends on how you setup the clutching
backshifting is VERY quick.
clutches require rebuilding quite often. snowmobiles rarely last over 5-6k miles
initial clutch setup would take huge amounts of testing as it is totally different from the designed vehicle and environment.

the 4tec engines are 3 cylinder 4 stroke engines. arctic cat just came out with a 2 cylinder 4 stroke turbo that makes 177hp stock. might be interesting as well.

Here's a Yamaha 1.8L 4 cylinder with gear driven supercharger. If the impeller is driven directly off the crank then I would think that an adapter could be made to adapt it to a car tranny.

Seems like a lot of work, maybe a lot of money, for questionable gain, but it looks like a fun project to tackle - there are a lot of pwerful PWC engines out there.

Too bad. Seemed like a lot of power. There was a series in the NorthEast for oval track cars that ran these. They were called "Cup Lights" and the series was run by a guy that's big in the snowmobile series. At least that's what I got from Google. Seems they faded away a year or two ago.

I think the "traction Control" comes from the way it will change ratio when the wheels start to slip. At least that was the case on a Motocross bike they used to make called the Rokon - another New England thing.





That sounds pretty suitable for a track build. I guess there is some advantage to a motorcycles built in transmission - but it's a mixed blessing with lack of reverse etc.

I suppose that a PWC or snowmobile generally outlast the motor where a motorcycle probably generates more crashed or broken vehicles with good motors. So maybe they're hard to get. A Yamaha 1800 cc sounds like an interesting item though.

I have seen 2 serious cases of 2 PWCs colliding. Of the 4 PWCs, one was repaired, one sank and was pretty much a total lose, and 2 were parted out.