242ls scorpion377 best prop?
 

Hi,

I have a formula 242 ls 89 with a new merc racing scorpion 377.
It had a 6.2mpi before that.
With the mpi it ran 51 at 5150 rpm with a enertia 17p
The scorpion does 57 mph with a enertia 21 at 5350 rpm with 3 people on board but that prop is still to small.
Have tried ballistic, appollo 4 blade and mirage plus none of those ran as good and fast as the enertia props.
Any other suggestions on the best prop for this hull?
The top end is most important to me

Those are gps numbers btw

How many hp is your engine?

Mercury black 6.2 is 320, Scorpion version is 340.

I don't know much about your hull but it looks like you're really damn close to your redline. I'm not sure what another 100 RPM is going to do for you.

Talk to a prop expert like BBlades and make sure you have a lot of test data. Time to plane, cruise speed and rpm, wot speed and rpm... speed at all different rpms help them help you dial it in.

Sounds like a cool setup, have any pics?

I will try to post some pics soon, its a merc racing scorpion so it is 377 hp at crankshaft, i wont have alot of testing left since my boat is almost the only one still in the water over here in belgium.
the enertia props are by far the best i have tested but they only make them to 22p.
another problem i have is that all the other props are very hard on steering its a single ram full hydraulic system.
with the apollo i cant turn the steering wheel at all at full speed.

appollo 4 blade 22p: 55mph at 5350 rpm bad holeshot cruising a bit faster
Mirage plus 23: 55.5 at 4950 bad holeshot and cavitating on turns
Ballistic 22xl: 56 at 5100 acceptable holeshot and cruising but still hard on steering
Enertia 21: 57 at 5350 good holeshot and cruising and best topspeed but still 150 rpm over redline

strange thing is here my prop slip on the previous engine 6.2 mpi was 8 percent with a enertia 17p and now with the 21 it has 19 percent so thats a big difference.
i was told to try an powertech ofs3 23p so i will try that next i think
Cavitation plate is mounted 1.5 inch above the bottom of the hull

http://i993.photobucket.com/albums/a...1032012230.jpg
http://i993.photobucket.com/albums/a...022_193015.jpg
http://i993.photobucket.com/albums/a...5012011216.jpg

Coop that's awesome. Getting these old Formulas to run just right with upgraded power sometimes takes time playing around with props, trust me I know.

For kicks have you played around with the Merc Prop Selector? You can just pick an engine with comparable hp and fill in all the data to see what prop it suggests and see if you are on the right track. It was close on both of my setups. Where do you do your boating?

The boat is in gent belgium, i will try the prop selector.