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View Full Version : Best Prop for more Top-End Speed


jkarp2112
11-03-2008, 01:57 AM
Anyone have a recommendation for a prop that will provide more speed on 86' PS ?

Also, what would be the standard top speed for this boat?

Much thanks for the help.

TMCNo1
11-03-2008, 06:29 AM
Contact Eric, here, http://www.ojprops.com/contact_us

jkarp2112
11-03-2008, 09:45 PM
Much thanks for the recommendation! I'll give Eric a call.

Laurel_Lake_Skier
11-04-2008, 08:52 PM
Also, what would be the standard top speed for this boat?


Assuming the engine, transmission, drive shaft and prop was all in good condition, top speed for your unloaded boat should be right around 41 or 42 mph measured with GPS. Don't put to much faith the the speedos .... Eric at OJ or Bill Weeks at Acme will want to know accurate speed (GPS) along with the rpm your engine is turning at that speed in order to make a prop recommendation. Chances are that unless you've done some engine work and added some HP to the stock engine, or you current prop is in tough shape, there will not be much room for picking up additional speed. One thing to keep in mind is that when you are talking about top speed, it takes quite a bit of additional power to add a relatively small amount of top end.

To give you an example, about a year and a half ago I was out to bump my top end up for barefooting. I started with a CNC prop and picked up .3 mph and a great deal of smoothness. Next I replaced the (perfectly good) heads with a pair of GT-40ps and the intake manifold with an Edlebrock Performer. After playing with the carb jetting and ignition timing I gained another 3.2 mph on the top. I'm not sure how much extra speed you are looking for but the bottom line is that you are not going to see very large gains even with engine mods.

spanielman50
11-04-2008, 09:26 PM
I Have A 88 Powerslot And My New Acme Added 3 Mph,,,,,,,,,46 Mph And No Over Reving,,,,,,,check Out Acme Before You Buy An Oj,,,,love My Acme,steers Easier
And Handle Way Better

jkarp2112
11-05-2008, 04:28 PM
The prop has a decent ding so it needs to be replaced - that's why I started this thread.

Unfortunately I don't have the $$$ to build up the engine so the right prop is really my only option for some extra top end.

If I were to push 45 mph that would be plenty - it's mainly so i can cover the longer cruises up-lake more quickly.

And really, those out there with 70mph runabouts...how much can you run at top speed?

I really do want the *best* made prop out there. I will pay extra for quality (that's why I purchased a 22 year old Mastercraft instead of something newer).

I've heard OJ, ACME, and I also have a special place for Dyna-Jet cupped 3-blade from Michigan Wheel as they are located in my hometown ;)

Here's their link to ski-boat props: http://www.miwheel.com/MIWheel/products/inboard/mich_prop_ski.htm

Thanks everyone!

russlars
11-05-2008, 05:45 PM
I think you are moving in the right direction to get a new prop. The new CNC props really do perform better than their predecessors. I have been very pleased with the handling and performance with the ACME 541 that I upgraded to and the nice thing about working with either Bill at ACME or Eric at OJ is that they will allow you to try before you buy which is a big plus!

Upper Michigan Prostar190
11-05-2008, 06:17 PM
I would ask Freddy.

Laurel_Lake_Skier
11-06-2008, 05:32 PM
The prop has a decent ding so it needs to be replaced - that's why I started this thread.

If I were to push 45 mph that would be plenty - it's mainly so i can cover the longer cruises up-lake more quickly.



If you have any sort of prop damage, you will notice an improvement. The CNC props from Acme or OJ are the route to take. I'd say you'll be fortunate to see an actual 45 mph but you never know.

spanielman50
11-06-2008, 08:30 PM
Acme If You Have A Powerslot

Covi
11-29-2008, 06:11 PM
I own an 86' with original prop no nicks or dings. My engine has had no mods that would change HP. That said my top speed (speedos) is 43 mph. I can say this doesn't happen very often at all.


Anyone have a recommendation for a prop that will provide more speed on 86' PS ?

Also, what would be the standard top speed for this boat?

Much thanks for the help.

TMCNo1
11-29-2008, 07:49 PM
I own an 86' with original prop no nicks or dings. My engine has had no mods that would change HP. That said my top speed (speedos) is 43 mph. I can say this doesn't happen very often at all.

That's about normal if the speedos are calibrated properly and/or verified with GPS!

JohnE
11-29-2008, 08:36 PM
I Have A 88 Powerslot And My New Acme Added 3 Mph,,,,,,,,,46 Mph And No Over Reving,,,,,,,check Out Acme Before You Buy An Oj,,,,love My Acme,steers Easier
And Handle Way Better


Any acme, or is there a special "just for mastercraft acme"? I don't doubt that acme makes a good product. But OJ makes them as good or better. I'm sure either place can get anyone exactly what they need to make their boat run optimally.

denverd1
12-02-2008, 03:06 PM
seems like a little more cup could be in order vs. the stock prop from '86. But, contact the guys who know.


If you want a contact @ Acme, Karl @ boarditup.com is the guy.

flipper
12-02-2008, 03:24 PM
Contact Eric, here, http://www.ojprops.com/contact_us

nuff said.........

TRBenj
12-03-2008, 11:19 AM
seems like a little more cup could be in order vs. the stock prop from '86. But, contact the guys who know.


If you want a contact @ Acme, Karl @ boarditup.com is the guy.
Im not so sure about that- selecting a prop is a balancing act. To maximize top end, the size of the prop (mainly pitch and cup, though diameter plays a role as well) need to be matched to the powerband of the engine. There is no sure-fire recipe for increasing top end speed- if you add pitch or cup (both of which decrease RPM's) and prevent the engine from reaching the speed at which it develops maximum power, you'll slow down. Likewise, if you dial back the pitch and/or cup (thereby increasing RPM's) and overshoot the hp curve by too much, youll slow down as well.

There are also other propeller design factors that come into play that must be balanced- rake, blade area size, etc. These have an effect on top end, holeshot, bowrise/attitude, and more.

If youre considering an Acme prop, talk to Bill Weeks at Acme- he knows his stuff. I wouldnt necessarily buy from him though- he has to charge full list price in order to protect his dealer network.

Jesus_Freak
12-04-2008, 12:33 PM
Im not so sure about that- selecting a prop is a balancing act. To maximize top end, the size of the prop (mainly pitch and cup, though diameter plays a role as well) need to be matched to the powerband of the engine. There is no sure-fire recipe for increasing top end speed- if you add pitch or cup (both of which decrease RPM's) and prevent the engine from reaching the speed at which it develops maximum power, you'll slow down. Likewise, if you dial back the pitch and/or cup (thereby increasing RPM's) and overshoot the hp curve by too much, youll slow down as well.

There are also other propeller design factors that come into play that must be balanced- rake, blade area size, etc. These have an effect on top end, holeshot, bowrise/attitude, and more.


The only thing you missed that I can think of is material of construction. In some experimentation I did on a stern drive, it was not a true balancing act. I moved from a composite to a SS prop (with similar geometric attributes) and saw a substantial gain in both holeshot and top speed. Longer story, but a point worth making.

TRBenj
12-04-2008, 02:54 PM
The only thing you missed that I can think of is material of construction. In some experimentation I did on a stern drive, it was not a true balancing act. I moved from a composite to a SS prop (with similar geometric attributes) and saw a substantial gain in both holeshot and top speed. Longer story, but a point worth making.

Good point, but I did say "other design factors, etc".:D

Material will also come into play a lot less on our inboards- everything Ive heard indicates that the new CNC NiBrAl props offer superior performance compared to all the others- even the stainless ones. SS certainly seems the way to go on a I/O or outboard though- and I agree that those composite props (we put a comprop on an old Glastron) are terrible.

denverd1
12-05-2008, 10:40 AM
Yea, the cup was just a thought, i'd trust the guys listed above. Certainly, props have improved over the last 20 yrs...