For a ‘17 Prostar with Ilmor 5.7 At around sea level and our crew is skiing between 32-34 mph and 15-32 off. What do you feel is the prop (3 or 4 blade/prop model) that gives the best pull/holeshot while keeping the rpm in a normal range (around 3300
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[email protected] mph). Don’t want or need a prop that provides stump pulling power but revs to the moon at ski speeds. Thanks in advance.
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I called OJ before purchasing, telling Eric I just wanted a little more top end, and if the rpm's could be lowered at all. I was actually curious if a 3 blade might be better for my needs, but he said the 4 was the better wheel for the Prostar 5.7. Our elevation is only 800' above sea FWIW.
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Runs 200 rpm lower and gets 1-2 mph more top end.
Without sacrifice to skiing. For a 32 Off and longer skier, not sure the power band change would be that much different.
5.7 has plenty of holeshot. I don’t know many people that “drop the hammer” on any modern boat.
Don’t care about top speed.
Same work has to get done so x amount of fuel have to get converted to heat to do the same work .
I suspect fuel savings to be marginal.
Engine life, also negligible savings and even possibly counterproductive
Fewer power pulses for same distance traveled means each pulse has to have more energy to get same work done than at the higher rpm , thus higher peak side loads on pistons.
If these engines are babied with frequent, quality oil changes like most are, the modern roller cam engine has extensive life ahead of it
I dont remember the rpms at 36mph, or the max rpm on that engine, but I believe I did do the math before, and we're right around 80% max rpm at 36mph. As long as we are at or below that, I don't think we need to worry about engine life.
2022 Approved Tow Boats
My course at the lake house on a public lake is very shallow at one end. As a result I have at least one of each of these iterations. Each iteration is an improvement in lowering RPMs w/o any lose of hole shot. And if you're a frequent OJ customer, they start sending you t-shirts w/ you prop purchases and repairs