I know the less the better, but what is an acceptable range? I'm at 10% now turning 4900 RPM with 28'' Bravo Ones. The rev limiter is set at 5100 0r 5150, just trying to figure if I should have the 28's lab finished, or try some 26".

Thanks Kirk

hope this helps:

optimum slip ratio by bam marine

find your slip by bam marine

Thanks timucin, that is very helpfull.

Kirk

Try some 28's and have your computer recalibrated for more HP and a higher revlimiter. It will wake up your boat all around - Holeshot (props), midrange (computer), top speed (props & computer)
See here. . . . .
http://www.offshoreonly.com/forum/sh...threadid=32609

Hey Bill, Who recalibrated your computer, and what is the rev limiter set at now?

Kirk

I went from 17% with every three blade I tried to 5% with a Mercury Rev4. 1992 Four Winns Liberator hull. Top speed was up about 1mph by gps but rpms dropped about 600. To say the least, Rev4's hookup. The blade area is huge. I also can get more postive trim as it holds the ater before blowing out better. According to the above calculator, 5% is only achievable with a cat hull, not an old semi perfrmance hull like mine. Testing is the only way to know for sure.

KN,
I left out some info: Computer was re-cal on my old boat w/ a 502.

I hope that someone (Dustin Whipple) will be able to re-cal the computers on my 496.

According to my tach, I am running 5200 w/ my labbed props on twinn 496HO's. I am getting a beep every so often, so I want to try labbed 30's.

Intolerant-I'd hate to burst your bubble, but you're not at 5%. I'd have to guess that the rev4 actually has more pitch than what it's listed as. That would skew the numbers to a lower slip.

It has a ton of cup which makes the big difference. Either way, top speed is exactly the same but rpm down 600. I lost 4mph with a Mirage Plus so this prop works for my boay anyway. As far as my bubble is concerned, dont pop it...you may let some germs in

Hi what pitch is the rev 4 you are running and what pitch was the Mirage Plus. Charlie