Prop or Engine RPM?

[Mswwi]

I have a VP 6.2 380 and 2.14 DPS-B drive.

Currently propped with FH4.

Boat pulls out of the water fantastic. Problem is I can only get 5300 RPMs Absolute max and 41 mph.

This is at +1 trim. Any higher degree and I get cavitation but obviously I get RPMs.

Boat was delivered to Florida sea level but I'm on Lake Michigan.

Looking to get my 51 mph as spec ed. I'm struggling to understand the pitch and how it translates to Volvo FH

[Big Block Power]

You sure the drive is getting trimmed?
You need more rpms so you would go to fh2 or more which I think is crazy. No one around here with a 380 is using those props. Something else is going on.

[Stagdad]

I have personally experienced that what gear ratio is on the placard may not be what is installed inside the housing. With drive engaged, Verify that engine turns 2.14 crankshaft revolutions for 1 prop rotation. Someone at the factory could have installed a 2.32. That could be one possibility....

[Mswwi]

You sure the drive is getting trimmed?
You need more rpms so you would go to fh2 or more which I think is crazy. No one around here with a 380 is using those props. Something else is going on.

Not sure how else I can answer that to prove that I'm sure.

"This is at +1 deg trim. Any higher degree and I get cavitation but obviously I get RPMs."

Starts at -7 deg trim.

[dustinm]

To get to your now max achieved rpm, how far do you have to push the throttle ahead? I reach max rpm at about 3/4 travel. Any more than that doesn't matter the computer does its thing with rpm.

[Snowman8]

I have an older 2014 R5 with the VP380 with the same gear ratio, 2.14 and FH4’s. My boat jumps up on plane and will top out about 50-52 depending on load and current. We mainly boat on a river so we are either going upstream or downstream. It’s been a while but it runs at WOT right around 6000rpm. Again it’s been a while since I’ve run WOT so I am testing my memory and I don’t have the auto trim but I think can manually trim up over 5 or 6 without cavitation at WOT. I normally run in the low 30’s trimmed around 2-3 depending on waves. If the waves get big I trim down a little and use the trim tabs to force the bow down to cut the waves for a better ride.