Prop rpm for a Velocity 22
 

I am going to repower a Velocity 22 with about 400hp. I am interested in knowing what my prop rpm should be. I would like to top out between 75 and 85 mph with a Bravo 1

Thank you,

John

Re: Prop rpm for a Velocity 22
 

What is the base motor ie: make and model.

Julie

Re: Prop rpm for a Velocity 22
 

Obviously the engine configuration is key.

Here is an example.............

5200 engine rpm with a 1.5 gear ratio turning a 28 pitch propeller with 13% slip nets 80mph.

Re: Prop rpm for a Velocity 22
 

I am loking at a Merc 502at 5200rpm or using a Mazda 20b with about 7000 rpm.

bbladesprops. It looks, by your example, that a 28 pitch should be turning 3500 rpm at the shaft. I am assuming 15" diameter.

John

Re: Prop rpm for a Velocity 22
 

If it is the mercury 502 then you will need to run at 5000 RPM at WOT. I cannot make a recommendation for the Mazda motor, sorry.

Julie

Re: Prop rpm for a Velocity 22
 

Yes, with a 1.5 gear ratio @ 5200 the prop would turn 3467 rpm. The Bravo 1's are 15-15.25" diameter even though they are "all advertised as 15.25" Also, the true pitch is aprox. .75"-1" lower than stamped.

Re: Prop rpm for a Velocity 22
 

What rpm you turn depends on what rpm the engine was designed for.

Change the prop pitch acccordingly to put your rpms in the correct range.

What drive???? A bravo will more than likely not like 7000rpms.

Re: Prop rpm for a Velocity 22
 

With 7000 rpm I will need a 2:1 gear reduction to yield that 3500 prop rpm. Thank you. This is the info I was looking for. I was trying to figure out the prop rpm that most props were most efficient at.

John

Re: Prop rpm for a Velocity 22
 

Save yourself some heartache a mazda 20d will never make enough torque to push your boat the way you hope. I know it will make plenty of HP but it will not work well in a boat. Stick with the BB chevy

Re: Prop rpm for a Velocity 22
 

guessing 28 bravo