Questions on getting my prop repitched.

[mthomps]

I have an older skat 10/18 race prop that I'm running now. It's in perfect shape but I am considering getting it repitched this winter for a low-mid pull instead of a mid-high mid pull. Do you think this is worthwhile and what would you say the effective new pitch would be? Would it be a better idea to get a 9/15 hooker or something?

Also there is a prop shop local to me who fixed a bent up 15.5 skat a few years ago and it looked like new. Would any good shop be able to do the variable pitch changes we run?

 

[kevbo]

You can bend the old 10-18 and make it pull a lot better but it wont have the hookup that a large hub has. If you ride in anything but glass, you need a large hub impeller.

 

[mthomps]

NEED is a strong word. I'm fine with this thing for now but its possible this local shop can repitch it affordably. If that's the case what do you think I should have them take it too? 8/16? 9/17?

 

[N3vrSat1sfied]

Skat only charges $65 I think. Last time Glen turned my around in a few days.

 

[mthomps]

Noted and thank you. But what pitch would you recommend?

 

[mthomps]

Anyone with a recommendation on re pitching my skat 10/18? Someone has had to have done this !!!! Speak up please, I need the advice.

 

[N3vrSat1sfied]

what engine? ski? etc.... If you are going to have Skat repitch it, Glen will help you determine what would be best for your neeeds.

 

[mthomps]

I wanted to have this local shop do it because I like them but I haven't contacted them on it yet because I'm still researching. Prop pitch confuses the living f*ck out of me I swear. I wish someone had a guide written up so we could easily check ourselves what's up. I have no interest in learning to to do it myself.

I have a 150-155 compression 650 6m6 engine with a black protec pipe and the old skat 10/18 prop. I rejetted to what protec told me. I think I am at 120 pilot 135 main jet and a 2.3 NS. I forget the spring's numbers.

Best I can describe it, it's not good compared to my friend's piped 701's with modern props and b-pipes as for as low rpm torque but its linear and predictible. The torque is all mid-upper mid, which allows me to yank and twist around on a wave going super fast but come on...I want that torque in the low to mid not mid to high and am hoping a cheap re pitch can get me that for a low cost

 

[Philip Clemmons]

If you're comparing an old straight blade to a newer swirl, they will never be close on hookup and acceleration. The new technology is here for a reason. I repitch props all day long, but it's best to ride a ski and determine what it needs by feel, not by comparing to another ski with different equipment. It's not apples to apples.


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[Quinc]

If you're comparing an old straight blade to a newer swirl, they will never be close on hookup and acceleration. The new technology is here for a reason. I repitch props all day long, but it's best to ride a ski and determine what it needs by feel, not by comparing to another ski with different equipment. It's not apples to apples.


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You haven't re pitched an older skat impeller for a similar setup?

I would call Dave at impros, or Skat and see what they recommend.

 

[mthomps]

Philip,

If you wrote a manual on props I would pay for a physical copy.

You said strait blade vs swirl...so my old prop is not a variable pitch???? it says 10/18 on the inside. So can a prop be non variable pitch but have 2 numbers?? I don't know what the heck is going on with this stuff guys! All I know is that if 50 bucks or so gives me a re-pitched prop locally I'll take it if I could get some advice on the matter because I'm just a cheap hillbilly who is thankful to even make it to the launch ramp.

 

[Philip Clemmons]

It's likely a variable pitch straight blade, where as the newer props are variable pitch swirls. They are completely different designs. Bottom end will never be the same. You're trying to make a Volkswagen a corvette. You're also comparing a protec to a b pipe. Too many variables. You can bore your nozzle and change your pump cone to help with bottom end. (I can do nozzle boring and get you a cone). I don't think you'll ever match your buddy with just repitch ing or tuning the pump. It will get better, but may still fall short of how his performs. Until you guys run identical equipment, it's tough to compare.


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[Philip Clemmons]

You haven't re pitched an older skat impeller for a similar setup?

I would call Dave at impros, or Skat and see what they recommend.

I've repitched plenty, but that doesn't make them perform like a swirl.

It's responses like this that make me regret trying to help. Someone's always an expert and critic.

I've been an Impros dealer for the last 6 years, and have worked with Dave closely on many projects. We worked directly with Glen for our custom world finals prop for the new TPE 900 competition engine we debuted.

So many people miss the mechanics of what's going on in a system, that they make poor decisions in trying to remedy issues.

It's like saying "what type 8.5" slick should I run to keep up with my buddies camaro (on 16.5" wide slicks)"? While there may be better tires than what you're on, you'll never match the traction of a bigger tire.

Best of luck to you.


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[mthomps]

Don't take offense to Mr Quinc, Phillip. I personally have mad respect for what you do and I'm sure he does as well. This is small time stuff. We are talking about repitching old small hub props afterall.

Again if anyone has a recommendation on pitch I'll def consider it seriously. Winter is long. Maybe I'll 9/15 hooker myself afterall. My friends skis tear mine apart and they have great props with piped and tuned 701's.

Anyone have an idea on a repitch for my 10/18 race skat prop? If anything I'm going to just repitch it 6/15 and then poop my pants over too much torque or not enough.

I want torgue happening every bit of the way because i like to eat poop and talk about it, lol.

 

[speedysprocket]

Philip,

If you wrote a manual on props I would pay for a physical copy.

You said strait blade vs swirl...so my old prop is not a variable pitch???? it says 10/18 on the inside. So can a prop be non variable pitch but have 2 numbers?? I don't know what the heck is going on with this stuff guys! All I know is that if 50 bucks or so gives me a re-pitched prop locally I'll take it if I could get some advice on the matter because I'm just a cheap hillbilly who is thankful to even make it to the launch ramp.

Swirl vs straight has to do with the leading edge of the prop. Your straight blade has, just that, a straight leading edge. The swirl has a curved leading edge.
And pitching your prop too low isn't going to make it feel any better than the propper pitch. It'll be like putting bicycle tires on the back of your dragster- you'll just sit there spinning them instead of going forward...

 

[mthomps]

I appreciate the help, fellas. Winter is long. Maybe I should just do it right.

 

[Quinc]

I've repitched plenty, but that doesn't make them perform like a swirl.

It's responses like this that make me regret trying to help. Someone's always an expert and critic.

I've been an Impros dealer for the last 6 years, and have worked with Dave closely on many projects. We worked directly with Glen for our custom world finals prop for the new TPE 900 competition engine we debuted.

So many people miss the mechanics of what's going on in a system, that they make poor decisions in trying to remedy issues.

It's like saying "what type 8.5" slick should I run to keep up with my buddies camaro (on 16.5" wide slicks)"? While there may be better tires than what you're on, you'll never match the traction of a bigger tire.

Best of luck to you.


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I must have missed something. I have only had one impeller re pitched by Dave and maybe it is impeller specific, (You could fill the outside of a barn with what I don't know) but for more bottom end is not as easy as re pitching the impeller a few degrees? Sure it wont be as good as if you bought the correct impeller..

 

[Philip Clemmons]

I must have missed something. I have only had one impeller re pitched by Dave and maybe it is impeller specific, (You could fill the outside of a barn with what I don't know) but for more bottom end is not as easy as re pitching the impeller a few degrees? Sure it wont be as good as if you bought the correct impeller..

Repitch ing a leading edge is far harder than doing the trailing edge, but that's not the point. He's comparing his old style to newer technology. A lower pitch could cause cavitation and make it worse. There is also a ton of pump tuning available to address bottom end without bending the prop, and if it's not what it needs, is an easy swap back. I'm just trying to be sure he has the right expectations. If I had the boat here I could have it dialed in no time, but I don't. People sometimes go the wrong way and compound their problem.


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[mthomps]

So many variables means so much confusion for me! I've def gained a better understanding of how pumps work. I'll have a lot to think about this next ice age here in Cleveland...lol :}