312 fastech prop help/nose cones?
 

I'm turning 30'p Bravo-1's that I had labbed?????? I'm getting 72 at 5100-5200 rpms on twin 454mag mpi's 1.65 gears,, seem's like my slip is still high,, Would nose cones help with this Fastech hull. The cruise seems good..
Seems like if I could lower the slip I could raise the speed 3-4mph...:drink:

I had the same boat with 502 mags.......74 GPS was all I could get out of it. (on a good day)

I put a Hydra-Motive cone on my Bravo last season. It was the best thing I could have done. I run low to mid 80's in a Velocity 280. The stability at the upper range and low speed handling is worth it alone. I haven't been able to do any real speed testing yet, although I was able to hit 82 with three more people in the boat.

I have a 2001 312 Fastech with 454 Mags too. I can only get 4,500 RPMs at WOT. Is 1.65 stock?

Thanks.

They all came with 1.65's and 30's that I'm aware of (except 454 mpi's came with 28's). If your only getting 4,500 and using 30P Bravos someone changed the gear ratio or your props are F'ed up. If you do have 1.50 drives you will likely need 26P Bravo props.

I guess I'll have the tech check when I winterize. What gear ratio/prop combo is best? Also, the props look ok... they are Bravo I props with no visible damage. What should I look for to determine if they are F'ed up?

You can't...I've had props worked to gain/loose 300-400 rpms and couldn't tell the difference from before/after. The easiest thing would be to borrow another set of props and see what you get.

The letters; "B R A V O"

YOu should get more than that,, with 4 blade Bravo-1 28 i was hitting the rev limiter and had it raised to 5400.
I do have off shore exhaust and took off the silent thunder, also vortech breather.

:eek:your slip is 20%, good is 10 to 15 %. I have a friend that went from 1.50 to 1.36 = 32 b1 to a 24b1 at 5800 rpm he is doing 94, his slip is 5 or 6% on a 05 31sutphen single. also he has a imco shortie which he thinks helped him, it did on my baja ol24 I went from 76 to mid 80s then my parts were stolen. right know I have a konrad ace xfactor drive and ext box with 1.50 gears. high X too. testing next week with 30s and 32s 4 and 5 blades.if not a good combo I will lower the gears. I plan on running 6000 to 6400 WFO. thats what my motor was set up for so cruising should be 60 to 70 between 3500 to 4000rpm. slip hope for a max of 10 to 12% if its lower thats better. you can change your gears by buying imco shorties with max marine inners = propshaft bearings imco comes with vertical shaft non polish is faster gear case. and get 1 1/4'' propshaft. or just the cases and have your gears switched. the other guy with a 4500 rpm sounds like the wrong gear prop go to a 26 prop. good luck and talk to Brett at BBLADES for labbing props for less slip. art