Other why do snowmobile engines make more hp per cc than watercraft 2 strokes?

[ATS_Aaron]

Your answers are all correct. Because of the CVT the snowmobile engine can be tuned to a very narrow (by comparison) power band. That power band is also at a very high rpm, higher than our jet pumps can efficiently operate at. Here is an example. The following graph is a Jaws triple piped Yamaha Viper 700 snowmobile dyno:

Sure it makes a peak of 142hp, but that is at 9000 screaming rpm. Notice that at 7000 rpm the hp is like 30% less. I haven't seen any dyno's to confirm the power continues to fall like that at lower rpms, but I suspect that at 5000 rpm it could be down to 50hp or less.

Aaron

 

[Dustin Mustangs]

i took a guess with the port timing on my engine. It's an 800 ves right now. Total loss, 46 sbns, v force 3, and a powerfactor pipe. It sounds incredible compared to my octane. I've got two more engines i put together and can't wait to try. A ported 800 with slp head, and a 900cc setup i haven't been this excited in a long time haha

Post a build thread on this pretty please!!!

 

[AlbanyMotorsports]

polaris power

 

[Billybo455]

Your answers are all correct. Because of the CVT the snowmobile engine can be tuned to a very narrow (by comparison) power band. That power band is also at a very high rpm, higher than our jet pumps can efficiently operate at. Here is an example. The following graph is a Jaws triple piped Yamaha Viper 700 snowmobile dyno:

Sure it makes a peak of 142hp, but that is at 9000 screaming rpm. Notice that at 7000 rpm the hp is like 30% less. I haven't seen any dyno's to confirm the power continues to fall like that at lower rpms, but I suspect that at 5000 rpm it could be down to 50hp or less.

Aaron

not to be a hater here buddy, but why would you pick a low cc triple, with triple pipes? that's a high rpm setup from the start. who is going to take the time to build an sj sized motor? not to mention. port timing on the polaris sled is looking fairly easy to get around. there's a reason malone and lenzi's big dollar motor is polaris based.

 

[rkm]

1000LD Cat would be perfect. 160-170 hp at 7000-7200 rpm. And thats stock. Even with a inefficient watercraft exhaust, it would rock.