proper prop
 

have a 1995 419 formula with trip 500s currently have 3 blade mirage plus that are a 25p turning about 4600 rpm at top end around 70mph cruises at 3100 rpm at 48 mph. Seems like there should be higher rpm at top end any suggestions. Thanks Mark

Got to be a better set up

Re: proper prop
 

HEllo Mark,

Can you tell me your gear ratio please? I used 1.5 for a ratio and come up with 4% slip which is not possible on a vee bottom boat. I very well may have your gear ratio incorrect. If you indeed have 1.5 gears then we need to look at verifying your recording devises. Let me know.

Julie

Re: proper prop
 

most formulas are 1.36

Re: proper prop
 

Hello,

Even with a 1:36.1 ratio you would be running very well for that boat. Between 11-13% slip depending on the rpm's.

Your R's are low for 500's. We would like to see you at at least 5000 WOT. Labbing the props will help your top end and save the motors, but won't help the cruise speeds.

What is the ultimate goal? Top end?

Re: proper prop
 

Keep cruise where it is and find the rpm on top. I figured 5000rpm also. thought about labbing but didnt know if what I had was right to begin with. Not sure what the gears are will find out. Thanks Mark

Re: proper prop
 

they are 1.5 and if anything top end rpm sometimes around 4400 just depends on conditions

Re: proper prop
 

Make sure the tach is reading correct and the the speed reading is accurate too. Your slip % does seem low.

Labbing the props you have sounds like a good option at this point.