Wrong prop?

[zeezer]

I recently purchased a 14 1/2 x 24 pitch ballistic prop for a 1989 5.7l mercruiser 260 hp sterndrive. The boat runs fine, but not great, with the stock 13 3/4 21p aluminum (recently referbished) prop. I went from 4500-4600 rpm WOT to 3300-3400 with the Ballistic. Iboats told me that prop should work fine with that boat & motor. I have only had the Ballistic on for 1 hour & put the aluminum back on. When reading the Mercruiser book it tells me that the motor will lose 300-400 rpm per 1 inch of pitch. <br />That makes sense 24p-21p=3. 3x400rpm=1200rpm<br />4600rpm-1200rpm=3400rpm. <br />What is the diameter & pitch in Stainless that will give me better performance without killing my rpms?????

 

[vipzach]

Re: Wrong prop?

What do you mean by "The boat runs fine, but not great"? Does the motor run great, it just doesn't have the performance you want? What are you trying to accomplish with a new prop?

 

[Deep Blue Water]

Re: Wrong prop?

I recently went from a 21 picth al to a 21 ballistic prop. I stayed with the same pitch due to the fact that the al prop will flex and the ballistic prop is cupped a lot more than the al prop. My WOT RPM is now the same as before but my top speed is 5mph faster. Sounds like you should have stayed with the same pitch as the stock prop, you got bad advice send it back and get the 21 pitch.

 

[zeezer]

Re: Wrong prop?

Vipzach, The engine & drive are just fine. I would just like to get better bite from takeoff & more top end. The craft goes 42mph (on gps)with the stock aluminum prop. This boat should easily do high 40's to low 50's<br /><br />Deep blue, they won't take back a prop that was mounted & in the water. What diameter is your ballistic? I think that it's the combination of larger diameter & pitch that's killing me.

 

[Deep Blue Water]

Re: Wrong prop?

I think my diameter was 14 1/4. I would worry more about the 3" pitch diff. than the diameter.<br />The 24p is killing you, and will kill your motor if your not carefull.

 

[QC]

Re: Wrong prop?

Originally posted by zeezer:<br /> This boat should easily do high 40's to low 50's

There's no boat info here that I can see. What makes you think that you can run that much faster? <br />

Originally posted by zeezer:<br /> I think that it's the combination of larger diameter & pitch that's killing me.

Yup, your own calcs tell you that, although, I would not worry about the diameter at this point. Just stick with pitch. This is very similar to going with bigger tires on a car or higher gearing. There's just not enough horsepower to turn that much pitch. With some boat data, we could probably help you zero in on it a little, but from what I can see 21P is right for you.

 

[bluewater19]

Re: Wrong prop?

try a 21 pitch laser II for top speed<br />With the 350 you could also try a mirage plus if it is a bigger boat that hauls.<br />What kind of boat is it???????<br />You could use a high five 21 pitch if you really like that "Killer Hole Shot".

 

[crazy charlie]

Re: Wrong prop?

Originally posted by zeezer:<br />[QB] I would just like to get better bite from takeoff & more top end. <br />Sorry Dude,you cant have your cake and eat it too.If you want" better bite from take off" it will cost you some top end speed and if you want "more top end "you will get less bite.Thats the way it works.You cant get both.Charlie

 

[zeezer]

Re: Wrong prop?

Sorry all, It is a 1989 wellcraft 23ft nova xl. I think it weighs about 4500 lbs. The reason that I think that it will go faster is because I had a different one about 15 years ago that went low 50's.<br />I just cant remember what which prop/pitch I had on it. Sounds like the 21 in pitch stainless is the way to go.

 

[QC]

Re: Wrong prop?

Zeezer,<br /><br />I have a 2001 23 footer with a 6.2 MPI 320 bhp and I barely get into the 50's. I saw 55 (GPS) once with nobody in the boat and a 22 inch pitch. I had a '95 TBI 5.7 in a VERY light 20 footer and it hit the same speeds as my current boat, maybe slightly faster.<br /><br />I don't believe your boat can get in the 50's with a stock carbed 350 period, and I'll bet you $1M it will never swing a 24 inch pitch . . .<br /><br />2001<br /><br />

<br /><br />1995<br /><br />

 

[zeezer]

Re: Wrong prop?

Ok Quite cat I'll take your word for it. So the 21 pitch is probably the best spinner for my application. Thanks again! <br /><br />Nice rig(s) by the way..............

 

[QC]

Re: Wrong prop?

Thanks. I think the others recommendations are pretty good. Check posts from Walleyehed (very strong on props) and the FAQ section. Good info there.

 

[Roy Edwards]

Re: Wrong prop?

I am new here but I have been doing a little internet research on props. Carzy Charlie said that you can not have your cake and eat it too. Thats what i have found out as well with one possible exception. It is called a torque shift prop mad by land and see. I do not own one nor have I heard any first hand testmonials but I did checkout their website and watched the video. This prop self adjusts to allow for a great hole shot as well as good top end speed maybe you should check it out. The website did not have prices (I am sure its very expensive) maybe its an option. <br /><br />have a great day

 

[Bondo]

Re: Wrong prop?

Originally posted by SilentBandit:<br /> I am new here but I have been doing a little internet research on props. Carzy Charlie said that you can not have your cake and eat it too. Thats what i have found out as well with one possible exception. It is called a torque shift prop mad by land and see. I do not own one nor have I heard any first hand testmonials but I did checkout their website and watched the video. This prop self adjusts to allow for a great hole shot as well as good top end speed maybe you should check it out. The website did not have prices (I am sure its very expensive) maybe its an option. <br /><br />have a great day

I've got 1.............<br /><br />Yes,...... I Do have My cake,+ Eating it Too....... <br /><br />Do a seach on My name, member #,+ Torque Shift Prop........<br />I've posted quite alot of info on it.........<br />Mine starts out at 11"s of pitch,+ Up-shifts to about 20/21"s..........<br />Holeshot that will RIP the arms Off a Skier,+ as Good or Better topend than I had before.........<br />Absolutely the Be$t Dollar$ I've Ever $pent on My Boat...............