Prop efficiency / speed vs recommended RPM question

[MengRanger]

I had a 2 stroke merc that would turn an A45 25 Tempest to about 5,700 RMP's. Below the recommended WOT, but was faster than any other props. I now have a 4 stroke merc and the A45 24 Tempest is only getting to about 5,600 RPM's, but is faster than any of the other props I have tested. So, if I am supposed to run 6,000 RPM's, would I expect a perfect A45 23 Tempest to be faster? Thanks

[PMantle]

I had a 2 stroke merc that would turn an A45 25 Tempest to about 5,700 RMP's. Below the recommended WOT, but was faster than any other props. I now have a 4 stroke merc and the A45 24 Tempest is only getting to about 5,600 RPM's, but is faster than any of the other props I have tested. So, if I am supposed to run 6,000 RPM's, would I expect a perfect A45 23 Tempest to be faster? Thanks

Run the numbers on a slip calculator.

[21XDC]

If your motor makes more horsepower at 6000 RPMs, then it could be faster going down in pitch. If the prop provides the same exact lift and efficiency.