Propeller selection info and speeds

[Silverbullet555]

I always try to clock the blades and I'll regrease the prop shaft.

Pretty stoked to get a set for $500.

I do need to sell the extra f9 set I have.

[cmattj]

Keep them for spares. Still amazing it had F9 but there are some Big hp Volvo guys that will buy them I'm sure.

[Silverbullet555]

Keep them for spares. Still amazing it had F9 but there are some Big hp Volvo guys that will buy them I'm sure.

I have 2 sets of f9s already which is why I considered selling one set.

[cmattj]

Keep them for spares. Still amazing it had F9 but there are some Big hp Volvo guys that will buy them I'm sure.

I have 2 sets of f9s already which is why I considered selling one set.

Ahh yes thats alot of props hanging around. People will talk Go make nice with Ebay and your new props will be free!

[Silverbullet555]

Finally got the f7 set in. They shipped to my dads house first. I don't use ebay so he bought them and I sent him a check.

Anyway, either they had new hubs out in or they simply didn't get used. One is more polished and there are some grease Mark's where the rear was mounted at least once.

Hoping to swap them tonight or tomorrow morning and see how they do.

[cmattj]

Finally got the f7 set in. They shipped to my dads house first. I don't use ebay so he bought them and I sent him a check.

Anyway, either they had new hubs out in or they simply didn't get used. One is more polished and there are some grease Mark's where the rear was mounted at least once.

Hoping to swap them tonight or tomorrow morning and see how they do.

They look good. Look forward to hearing your results!

[Silverbullet555]

They are on now and will be used next week at current altitude and a couple weeks after that at 5000 feet. Glad I keep the propnshafts greased with vp propnshaft grease. Slid right off.

[Midlifecrisis]

I'm revisiting this now that I have more information. Turns out I have F6s on it. I'm running it at 5,000 ft and looking to get better hole shot. WOT for this engine should be 5200, and I'm getting about 4500. It's a 2006 220 with Volvo Penta 5.7 GXi (320 HP). Would changing it to F5s make a big enough difference for out of the hole?

[Big Block Power]

Man your 700rpms away that is alot. Is that the only place you will be boating. Where was the boat used before you boat it? Sea level?
F5 isn't going to give you enough. You might gain 200-400rpm
I would drop to F4 and see where you are at. What gear ratio is it 1.92-1?
What shape are your F6s in?
Yes doing in pitch will help your hole shot and midrange. Getting your rpms up to 5200 will get you some speed back also.

[Midlifecrisis]

The rear F6 has a few dings in it. The forward one is fine. I'll probably keep them in case I run it a lower altitude.

It started its life at Folsom Lake in No Cal, around 500 ft in altitude. It had plenty of punch when I test drove it there...

How do I find out what the gear ratio is?

[Big Block Power]

There is a metal plate on the port side of the drive I believe it is. Yea hopefully prop change will work for you. You will have to let us know. Try to find a great used set of f4s and see what you get. Matt is the computer drive prop guy though. He'll chime in too. Really drive prob should get changed.

[cmattj]

Hey Mid.. BB is correct about the drive gear ratio as you’ve seen “ High Elevation “ set ups. At 5000 feet your 320 hp is down to 240hp ish. ( Density altitudes will be another subject)

When you change the Drive gear on the high elevation order from the factory, it increases the ratio . For example gear ratio is 1.95 at sea level.. Then to 2.32 for high elevation. Using for example the same F5 prop.

Higher gear ratio allows multiplication with that same prop.

So since we’re not going to change the gear set this is where you need to make a decision. BBP is correct to go to a F4 as that equals 4 inches less of pitch . ( pitch equals the inches pushed forward in 1 rotation).



You may have been 55-57 mph at Folsom lake but now sluggish to 44-46 mph. F4 prop ( 21 inches of pitch would get you back to 47-49mph.
F5 prop may give you better cruise speed but cause Full throttle lugging.

So currently your lugging , and for longevity it needs less prop. Find F4 for water sports, full load etc. That the sacrifices of 5000 ft. Elevation .

[Midlifecrisis]

cmattJ, thanks for the details. Keep in mind that the lake has a speed limit of 35 MPH, so top end speed is less of a concern than giving the boat enough grunt to pull my fat behind out of the water on a ski.

It sounds like the key to that is a shallower prop that will let the engine spin faster out of the hole without lugging - is that the way to look at it?

[akorcovelos]

I assume this is a volvo drive? Not my area of expertise, but Merc made a 4x3 dual prop Bravo 3 that greatly improves hole shot and maintains cruise speed at the cost of top end, did Volvo offer something similar?

[cmattj]

cmattJ, thanks for the details. Keep in mind that the lake has a speed limit of 35 MPH, so top end speed is less of a concern than giving the boat enough grunt to pull my fat behind out of the water on a ski.

It sounds like the key to that is a shallower prop that will let the engine spin faster out of the hole without lugging - is that the way to look at it?

Speed limit of 35?. Oh my (sigh)....

Yes as you read , and already suspected. Lower F series equals reduced forward pitch.
I may suggest then find some used F3 props to try. She’ll be in the sweet spot. F4 will still be a huge difference.