That could make sense also... but... that seems awful fast for his engine setup in a Rage.

Chris

You would be correct. The prop was cupped to bring my revs down 200. Unlike others who have labbed their props to bring their rpm number higher. Next I'll be hearing that 28's are faster than 25's with similar power.

Yup.. the prop cupping makes sense.. just seems pretty darn fast for a Rage with that amound of power... on the other hand.. the other two guys on here that have been commenting do live at a higher elevation.

I don't think that anyone thinks that 28's and 25's are the same speed given the same horsepower. The smaller/lighter Rage will be faster and quicker... unless the water gets rough, and then the bigger boat will do better.

The fastest single engine v-hull that I have personally seen, was a Rage with a twin-turbo motor in it, here on one of the local lakes. It did 115 mph if I remember correctly.

Chris

We do live higher (4500') but have run here & Havasu. I have 2 props for different altitudes. Most lakes around here are 6000'. I need an in between for Utah lake & Powell. I've recently rebuilt my 500 Whipple so haven't had a chance to test down there but my previous trips & Jon's (Desert Rage) recent trip with his 650+hp & turning my 32 merc lab @ Mohave got slightly slower results than this. He also ran a local labbed 28 down there & much slower, same revs. The cup may make some difference, but those slip #'s are cat kind of slip #, but if it works, more power to ya! Maybe we all need to add some more cup. Kinda like drag racing, power doesn't matter if you can't get it to the ground (water)

Jon actually took my 30 down to Mohave which runs exactly stock 30 numbers.
I believe he turned it right near 5500 and 86 mph (correct me if I'm wrong Jon) so cupping to get 7 mph is pure magic

Still looking for the answer to the GPS speedo question

That's right, at Mohave over Halloween I could hit 89.5 gps @ 5500 with 90MPHrage's Merc Labbed 32 and 86 @ 5400 with Dave's locally labbed 30. Elevation is aroung 620' and air temp was a wonderful 85.

5400 @ 86 mph is almost 16% slip. Every stock prop I've run on a Rage is right at 13% slip. So, your worked prop seems a little on the high side. 13% slip would put a 30 at 89+ MPH, now add 1" pitch for aggressive cupping and 93 @ 5450 seems possible on paper. Now will the boat run that with the power he's got???? Seems pretty fast. I know I guy with the exact same setup in a Rage and the best he's gotten is 86. With 7 lbs of boost and CMI's he's making around 675-700 HP.

xcpilot....

Is your speedo a GPS??

Have you verified your speed using 2 GPS's to make sure they are calibrated??

My Lavorsi analog GPS actually reads 1.5 mph slower at above 90 mph than my two digital GPS's and my calibrated radar gun.

By two or more witnesses shall all truth be established.

Chris

My slip has always been ~17%. Before & after lab.

Interesting. I've set up several Rages and they all come out under 14% slip using stock props. A 496 HO usually comes stock with a 26 Bravo 1 prop. With 17% slip that works out to 68 MPH at 5000 RPM. We all know an HO Rage runs low to mid 70's stock. My Rage runs 70 at 5000 RPM (on a scan tool) with a 26" Bravo 1 in hot weather, 72-73 at 4800 with 28Bravo 1 in cool weather. Another Rage I set up ran 80 with a 26" Bravo 1 at 5600 RPM (13% slip), It ran upper 90's after a blower addition with stock 30" at 5800-5900 RPM(13% slip). So, I'm a bit confused with you guys seeing so much slip with a Rage. Of course once you start labbing and modifying props all bets are off on calculating slip.