had some bottom work done and it brought my slip # down from 17% to 15 %
top speed right now is 78 with Bravo 28's at 5200 RPM
The question is - Will the slip factor stay the same at WOT after the props get labbed?
Because if it does that the calqulator says that my top speed should go up to 82.5 if I gain the usuall 300 RPM.

I have no idea what is normal. On my 34 Super Hawaii straight, 25 degree, bottom with notched transome. My slip went from 12% down to 9% using Bams slip calulator, after labbing my 25p Mirage Plusses. Slip when down and I picked up 200 rpm.

I'm very happy with Houston Propellars work.

I have never had a prop labbed but I would thing that the slip should stay the same or even go lower.

The slip should remain the same or drop a little. When lab finishing the cup is generally reduced which allows for an rpm increase. This also effectively reduces the pitch of the prop as well. It's important to know what the actual pitch is of the prop is when calculating pitch. If a prop was worked and cup added this effectively increases the pitch. So if the same pitch is entered into the slip calculation as was used prior to any prop work it would appear as if the slip decreased. Likewise if the cup is reduced (effectively reducing the pitch) and the same pitch is used for the slip calculation as was used prior to the prop work the slip would seem to increase.

Use slip as a tool. It may vary a little from prop to prop but when you get the slip close to where it should be then go with the set-up that works the best.

Thanks Payton,Darin