Prop Help please BBlades
 

I have a 22' 454/330 bravo 1 drive and I am spinning too much RPM. It is a deep drive boat. I started with a 22p Bravo 1 and was getting out of the hole great and getting about 54mph top end spinning 5000rpm. I went to a 23p Mirage plus (vents in) and got 57mph at 5000. I m trying to get down into the suggested WOT range of 4600-4700 and pick up top end. I was thinking about trying a 25p mirage but I lost a good bit out of the hole by going to the 23 mirage from the bravo and I dont want to kill it completely. Would I be able to run a smaller dia. prop like a laser in the 25p?

Thanks

Are your numbers gps? If your drive is 1.5 you should be in the 65mph area if your running 5k rpms on hte 23p m+ and 62ish for 22 p b1 Otherwise your getting a lot of slip!!

I would try a 24p b1 next or your rpm gauge is off??

Yes they are GPS numbers. I hve a non mag 454 so I think 5000 is running to high and not making power. I was thinking about a 24p hyro 4 blade. I am trying to get the rpm down to about 4700-4800.

and the Tach seems right, she is screaming at 5000.

If I went with the 24p bravo would I lose a lot of top end and cruise over a mirage+?

The 24 Bravo 1 should give you the better cruise speeds. Labbing the Bravo 1 tends to be a 2-4 mph gain.
Your slip % does seem to be high. Is your gear ratio 1.5:1?
Labbing the 25 M+ will give it planing times similar to the 23 M+ stock.

I do like the M+ on your hull since Mariahs are a little heavy and you do have a 454 which can overpower the smaller blade area of the Laser 2. However, we do have some Laser 2's for testing if you would like to try one.

Brett

Would the 24 bravo bring me down into my WOT 4700 rpm range and maybe pick up some MPH? Do you test bravos or something like a hydro? I am not to familiar with the Mariah hull, it seems I need more bow lift apposed to stern since it's a deep drive boat.

You sure you aren't trimming the drive up too much. My advice would be to start with the cav plate level with the hull and go to WOT. Watch the gps and rpms as you bump the trim in small increments noting the gps and tach as you increase trim until the boat slows down and rpm keeps increasing. At that point you are just over trimmed so go back to the previous drive trim and do your testing at that point.

22% slip is high for a deep drive. I do not believe that a 330 hp motor will pull to 5000 rpm at nominal 10-14% slip on your boat so you may be trimming too much.

Thanks, Thunder I'll give that a shot. I trim until I feel the sliip and then tap back down. Its starnge to me because I never had a deep drive boat before, my trim indicator says I am just under the half line but when I am at the top trailer position the prop is not even close to breaking the water when sitting. My Formula the props were up and out of the water all the way up. I don't rooster tail at all either, don't know if that helps.

Update, I repowered the boat with a 454 Mag MPI fresh rebuild. I took it out and I seem to be really out running the 23 M+. Iwas thinking of maybe going to a 25p M+ but wasnt sure about getting on plane. I was also interested in a 26p Bravo 1, any suggestions.