Alpha 1 Gen 2 Max RPM

[Mad Props]

Is there a max RPM limit on these drives listed anywhere? I see max RPM numbers listed for all the different motors but I'm wondering if the limit is based on the motor or the drive?

 

[shaw520]

Usually the motor, 4500 to 5200 depending on motor. With engine(s) running properly, RPMS should be dialed via correct prop pitch and diameter.

 

[achris]

Much more than about 6000 will see the drive 'un-assemble'....

The max revs quoted for an engine is to do with the camshaft. The cam determines maximum power (which it where the mex RPM comes from).. Yes you can put a cam in that makes lots more power, but at higher revs, and the trade off is lots less power at lower revs. Makes the engine pretty much useless as a boat engine.

Cams that produce good low end torque almost always have a low peak power RPM. And in a boat, that's good news. Strip racing, not so much.

Chris....

 

[Scott Danforth]

about 6000 like Chris mentioned. beyond that, the drive's lack of pressured lubrication will rear its head. they can be made to spin higher RPM's however out of the box 6k

however your cam profile to prevent reversion will limit you to 5500 RPM

 

[Mad Props]

Ok.. I was just curious.. Because when you but on a different pitch prop for a little better hole-shot, everyone says, watch your RPMs on the motor... but I wasn't entirely sure why... I figured it was because the valvetrain would start flying apart or the outdrive couldn't handle higher than 5k or so...

 

[achris]

Smaller prop does make the engine rev higher, and the reason to 'watch your revs' is because the back end of the power curve is not a place where engines are particularly happy. As you suggest, internals tend to become external.

Chris.

 

[Mad Props]

Ok, so that is really the answer to the original question lol... The max RPM is not due to the drive, its due to the engine. Either way, I don't like spending much time near the limits anyways... Theres that whole exponential degredation of life expectancy of things when you operate them near their limits. Just cuz its a limit doesn't mean you can run it hard and put it away wet and expect it to last.

 

[Scott Danforth]

most engines will float the valves prior to pistons swapping bores or ventilating the block. its the instant unloading followed by loading that makes things interesting. many motors come with rev limiters to prevent this, especially when launching the boat on a wave and instantly unloading the motor.

however I have witnessed first hand when motors grenade due to launching followed by submarining.