Do I need more pitch or more cup? Details inside.

[Matt's 175]

I am hitting 5000-5100 RPM's at WOT. Max recommended is 4800. The prop is a Stiletto Advantage II 14.25 x 19P. I have tried a 14.25 x 21P Stiletto and RPM dropped all the way to 4400 and I actually lost MPH. It seems that if they would make a Stiletto in a 20P, it would be absolutely perfect for me. Should I take my 19P and have it re-pitched to 20 or should I have more cup added to it? I have read that both methods will drop the RPM a little.

More details if needed:

135hp 3.0L MerCruiser
2.0 Ratio alpha drive
Bayliner 175 with 2 people aboard and gear, with 4 aboard I can still hit 5000 on a long run.
GPS speed 43.xxx

Also, how much should I expect to pay for re-pitching or re-cupping?

 

[Bondo]

Re: Do I need more pitch or more cup? Details inside.

Should I take my 19P and have it re-pitched to 20 or should I have more cup added to it? I have read that both methods will drop the RPM a little.

Yes...

 

[642mx]

Re: Do I need more pitch or more cup? Details inside.

Also, how much should I expect to pay for re-pitching or re-cupping?

A custom lab job will run you about $350.

 

[Matt's 175]

Re: Do I need more pitch or more cup? Details inside.

So... more pitch or have it cupped some more?

 

[642mx]

Re: Do I need more pitch or more cup? Details inside.

So... more pitch or have it cupped some more?

If your planning on labbing a prop, its better to be over-propped than under-propped.

 

[Matt's 175]

Re: Do I need more pitch or more cup? Details inside.

What is meant by "labbing a prop"?

Can't I just bring it in and say "I need this pitched up one inch'"?

 

[steelespike]

Re: Do I need more pitch or more cup? Details inside.

If your planning on labbing a prop, its better to be over-propped than under-propped.

I don't understand overpropped being better?It forces the motor to lug through its whole range.If under propped you can at least use it safely just don't over rev.

 

[642mx]

Re: Do I need more pitch or more cup? Details inside.

I don't understand overpropped being better?It forces the motor to lug through its whole range.If under propped you can at least use it safely just don't over rev.

I said, "If your planning on labbing a prop, its better to be over-propped than under-propped."

And if your going to have one labbed... its easier to start with too much prop and have some RPM added, then one that easily over-revs.

If your going to purchase a prop and install it without labbing it, then buy a prop that you can hit max RPM with.

 

[642mx]

Re: Do I need more pitch or more cup? Details inside.

What is meant by "labbing a prop"?

Can't I just bring it in and say "I need this pitched up one inch'"?

Labbing a prop is a process of making changes to a prop. Labbed props can eliminate the porpoising, increase holeshot times, increase top end, increase cruising speed, and even increase fuel economy. Of course they can't do all of this with one prop... but you send the prop in and tell them your concerns and what you want to accomplish with the labbing.

Have a look: http://www.bblades.com/