488r prop size

[roffey]

I have a 17.5 Thundercraft with a 3.7 488r and a alpha one outdrive. Currently I hit about 4800 rpm WOT with a 19 inch prop. Here's what I am thinking, I should increase the pitch and lower the rpm. Do you think my boat could handle a 23 or more pitch and if so should I be looking at 4 or 3 blade.

 

[steelespike]

Re: 488r prop size

Near as I can tell your Motor is rated for 4200-4600 rpm.
A 1" increase in pitch should put you at about 4600.
A 23 will kill your hole shot and could knock about 800 off your rpm.
A 4 blade in the same pitch could lower the rpm about 100-200 .
The 4 will usually improve hole shot,stay on plane easier at reduced throttle,seem smother and
should respond better around the dock.
It will usually cost a little top end.

 

[roffey]

Re: 488r prop size

Thanks for the info, I think I am going to go with a 20 inch 3 blade prop.

 

[jestor68]

Re: 488r prop size

Thanks for the info, I think I am going to go with a 20 inch 3 blade prop.

I assume that you're planning on a SS prop, as there isn't a 3 blade 20 available in aluminum.