OK - Not-So-Big Thumbs Down for Ballistic Prop

[TwoBallScrewBall]

Swapped out the OMC 14.5 X 19 SST (stainless) prop for a ballistic 14.5 X 19 stainless prop (see stupid human tricks). Boat performance went to hell.<br /><br />Holeshot was completely worse, took a much longer time to get on plane and to do it respecably required some trim tab while with the OMC I could have the tabs all the way up.<br /><br />WOT went from 43MPH at 5500RPM with the OMC to barely 5000, probably 4900, and 38MPH with the ballistic. <br /><br />Also with the OMC prop I can trim the motor up to about 5/8 of the way up the guage without ventilating, with the ballistic anything near half way up caused the prop to blow out. <br /><br />Very unhappy, I expected at least the same performance and maybe a little better with the ballistic. Am I doing something wrong?<br /><br />I ended up drilling 1/4" vent holes in the OMC and reinstalling it, right back to 43mph at 5500Rpm, with a better holeshot with the vents now. Going to try an aluminum 15X17 my dad has and see what that does for me.

 

[Dhadley]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

Wow...a Bull-istic that doesnt work as well as an SST. Amazing.<br /><br />No, you're not doing anything wrong. What you see is not unusual. Try raising the motor a tad with your SST.

 

[madbanchee]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

Speaking of props... Which props are thought to be better performers?

 

[TwoBallScrewBall]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

I was thinking of trying to raise the engine, but I thought it was supposed to have the cav plate about even with the hull which is how it's set up. The engine has four mount holes, and it's currently in the hole next to the top so I can go up 2 more holes, looks like 2 more inches. <br /><br />Is there a convenient spot to hook a hoist to this engine? I have a 2 ton cherry picker. <br /><br />Here is the setup. The hull is stepped, so I'm snot sure if the cav plate should be in reference to the lower part or the higher stepped part. Should I raise it to the top hole and just see what it does? <br /><br />HELP!!! <br /><br />Here is the current setup:<br /><br />

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[ob]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

From my view of the pics ,I'd guess you could raise the engine the two holes you have left without any problems.

 

[Dhadley]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

Yep, I do the same if it were me. Raise it the 2 holes. If it starts to vent on hard acceleration dont worry about it right now (it may not). We're just interested in getting the top R's up a bit.<br /><br />If it does start to vent we may look at something like a raker or even a Stiletto. If you have plans for a jackplate then we might look at Turbos, perhaps in the 4 blade style.<br /><br />Lets just raise the motor and take it one step (change) at a time. Watch your water pressure. Write everything down to compare it to your established baseline. If your uncertain about any part of your baseline, go test again before you change anything.

 

[TwoBallScrewBall]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

Thanks a lot for the help! I am going to take your advice, take a good baseline, then raise it all the way up and see what she does. I'll hopefully have some kind of update on it in a day or two. <br /><br />Raised it up to the highest hole. Piece of cake with the engine hoist and a wheel puller with grade 5 bolts. Water is horrendously rough today, so as soon as it calms down I'm going to dump it in for a test drive. <br /><br />To be continued...

 

[red10]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

Steve, i have basically the same stepin the hull and i'm using a stilleto and it's set in the same holes as you have. I tried raising the motor up 1 hole and it didn't like to hold on very well and not much trim range so back down i went ( where you have yours) and thats the best i can do.

 

[TwoBallScrewBall]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

The win d is still kicking up out there, but maybe later today I'll get a test run in. I'll post the results.

 

[TwoBallScrewBall]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

I took the test drive. Holeshot seems alot better, but I feel like I lost a lot of top end. The motor is spinning faster, I can get 40.5 on the gps at 5700rpm but it's 2mph less than I saw before and that was at 5400rpm. So I've bought holeshot for top end. I also feel like I'm crusising slower than I used to be. The other day I was worried about my gas level, so I crusied all the way home at 4000-4200Rpm which was 31-32mph. Today That same RPM sees like 26-29mph if that. <br /><br />I guess I'll move one hole down and see what kind of comprimise that is. Maybe another test tomorrow. Any suggestions? Should I see what the ballistic 14.5X19 does at this height first?

 

[LubeDude]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

Originally posted by Steve Huminski:<br />Should I see what the ballistic 14.5X19 does at this height first?

Yes, absolutly.

 

[walleyehed]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

I agree with Lubey...test that ballistic "thing".<br />I ran several on V4's, and to say the least, I was dissapointed in all. The only decent ballistic made so far has been the 4-blade 15 spline for large gearcases/higher HP apps....it's shown some impresive numbers there.<br />I wouldn't underestimate the capabilities of a good SST either..not the fanciest, but good performance over-all.

 

[Dhadley]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

Now was this with your 19 or your Dads 17?<br /><br />If its your 19 the results were to be expected. We gained top rpm, thats what we were after. All the way up may be a tad much for an SST (especially if it were an SST 1 - yours is an SST II -, worn - cup length reduced - or has been reworked). You should have lost some trim travel too (vents sooner in the trim range).<br /><br />Yes, I would try the Bull-istic just for reference. I would try your Dads 17 (if you havent) just so you can see what a large diameter does. Remember, right now were not after absolute top speed but just seeing how your hull and load reacts to changes in X dimension. BTW -- always test with the same load -- no matter what that load is/was.<br /><br />After you finish your tests you have a decision to make. Leave the motor up and look for a prop with more bite or adjust the height for the chosen prop you have now.<br /><br />Aint this fun??

 

[G DANE]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

Hi Steve<br /><br />If that little picture of your boat is at WOT, it explains a lot. You need bow lift. By raising motor and moving props forcecenter up, you lost bowlift too. Either you need a propeller with more bowlift or you need a bracket providing setback, to get your bow up. You have too much of the hull in water to get the best top-end.

 

[Dhadley]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

BTW -- how was the water pressure?

 

[TwoBallScrewBall]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

Hi guys,<br /><br />The testing I did was with my 14.5X19 SST. I don't have the 15X17 in hand yet. <br /><br />As far as the picture, that's the photo that was in the ad when I found the boat. I didn't take it and I wasn't driving. So I can't tell you what throttle that is.<br /><br />The water pressure stayed unchanged, steady 30-40psi depending on throttle. <br /><br />Odd thing is that I can still trim the engine to the same place on the guage without losing bite. Raising the engine on the transom didn't affect that. Though now if I make sharp turns at speed I get a lot of vibration. Prop does not really pick up speed, just makes a lot of noise and vibration. If I perform a more mellow turn it's fine, and actually it was fine all throughout my test drive execpt for when I intentionally turned very sharp. I also noticed the vibration if I trim the motor all the way down, I get a lot of weird vibration. Just does not sound right. <br /><br />I'm going to try the ballistic after work and see what it does. <br /><br />Thanks again for the help so far, and yes, this is fun. <br /><br />And what is implied by calling these props bull-istic? Just wondering...

 

[Dhadley]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

Ok, good info. That tells us that the cup is probably gone or worn at the furtherest point. Like I say, dont worry about the venting right now -- we just wanted to see how your hull, and water pump, respond to height.<br /><br />So far so good. Try the other props and see what happens. Remember -- put the same load (fuel and people) in as before.<br /><br />If you happen to find a Raker or Stiletto laying around, grab 'em. Try as many props as you can find.

 

[TwoBallScrewBall]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

I think what I really need to find lying around is another 200 to put next to this one.......

 

[Dhadley]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

Why?<br /><br />No room for 3???

 

[TwoBallScrewBall]

Re: OK - Not-So-Big Thumbs Down for Ballistic Prop

No 2 would be about it. Or a nice 300 single, that way I don't need to drill new holes. <br /><br />But for now I'm going to see what I can do playing with props and height.