36% slip?
 

took my 2004 magic wizard out for the first time yesterday and only ran 61 mph. that was @ 5000 rpm with a bravo 4 blade 30p prop. any ideas on what i should do. 1.5 ratio xr drive with a sportmaster lower. it would run 55@ 4300. this was at 5400ft of elevation but i think it should still run better. i'm new to the performance boat thing so any help would be great. thx, Tony

I calculate 31-34% slip at either elevation. Something is very wrong here. If these numbers are correct, you will be running a low 20's pitch propeller once the slip is harnessed.

What engine are you running and has the propeller ever been repaired or adjusted?

Brett

it has a 575sci with an intercooler pushing 8lbs of boost. i just bought the boat. it was a repo so i dont have any history. it looks like it has never been repaired but i really dont know.

i tested it several times yesterday. at 5000 rpm max speed on my gps was 61??? i have no clue which direction to go.

The elevation affects make sense and fall within the parameters of change. However, the performance is lack luster. From the little I know about this so far, it seems there may be engine and set up/propeller issues.

I'd try another propeller of smaller pitch and check the results.

Also, is the XR a shorty and how low below the boat bottom is the point of the gear case? Or is it above?

Brett

My guess is that your x dim is way off. I bet that your drive is to high with the shorty. That is why you are spining a 30p at 5000 rpm and only going 61. What is the prop shaft from the bottom of the at now?? You could also try going to a 5 blade but I would guess with that much slip your drive is way to high. IMO Brett will get you going the right way he know his stuff.

i just measured from the middle of the nose cone to the bottom of the boat is right at 6in. what pitch should i try?

He's running sci - shouldn't change w/elevation.

Definitely a problem with setup and/or engine.

An overly high x-dimension could cause major slipage like you're seeing. 6-inches seems high for a Wizard. If you drop the hammer at, say 4000 rpm, are you seeing a quick spin up to 5k? Could be aerating your prop.

Can you double check your prop size?

We had a nice conversation today and we have a game plan.

We'll wait to hear back on some possible water pick up issues. After that there is the propeller and then the engine and then back to the propeller. 1 step at a time.

CC, we are talking 6" below not above. This would be a conservative "X" dimention, not aggresive. Also, sci's are affected by elevation although not as severly as NA's.

Brett

So do we have a pick up that is messing up the water infront for the prop??? 6" sounds low to me. Keep us posted with the out come.

it looks like the water pick up may be a problem. gonna get it moved this week and test it this weekend. i'll keep you posted. thx again for all the help.

well here's where im at. ran the boat today after moving the intercooler pick-up. got 4600-4700 rpm and ran 63 mph.:bsflag: still lacking in the performance. next step? different prop is what im guesing. brett i'll be call'in you in the morning. Tony

THIS SUX! this boat should go low 70's even @ elevation. nothin ever comes easy does it?:drink:

Yeh, but we did make a forward move! I don't think that is BS.
We found a problem and a problem that may not be completely eliminated.

Takes time...........some times.

Brett

thanx brett:drink:

got my p5x yesterday from bblades. wether sux today and tomorrow looks like i'll giveit a runon sunday. i'll post the results.

got to the lake today and i have to say brett from bblades knocked it out of the park! with the p5x 26pitch the boat ran 72mph @ 5100rpm :evilb: