Max HP to a turbine ?

[ericrunner]

Im about to use everything out of a yamaha waverunner 650 including turbine to swap on my pontoon . My question is in a near future if i would swap the engine for a 4 stroke with more hp would my turbine steel work ?

[baeckmo]

First of all: you do NOT have a turbine, you have a pump! Turbine is a device that extracts mechanical energy FROM a fluid, while the pump is used to add mechanical energy TO the fluid.

Then, it depends on what power and rpm it is designed for originally, and what power/rpm characteristics the substitute has. Remember that for a pump of this kind, the power is proportional to the rpm^3, as long as the pump internals are kept constant. For waterjet units, thereare often a variety of impellers with different pitch settings available, so that matching is possible within a reasonable range.

[ericrunner]

thats what i was thinking . So if for example i would have a motor with more hp but the same rpm my top speed would remain the same but my take off would improve . And a bigger pump will provide more flow but needs more hp

[baeckmo]

Originally Posted by ericrunner

........ but the same rpm my top speed would remain the same but my take off would improve ........

With unchanged impeller and the same rpm, the pump will "swallow" the original hp, no matter what. That means there is no change in performance, neither in take off nor top speed. A jet is working at constant load (provided it is not cavitating), independent of advance speed. This is not the case with a propeller.