r015

Running a B1 drive with Max Machine Worx internals.

My question is how fast will a bravo one lower go, before the gear case would blow out at speed (not blow up) gear case blow out pushing the water out around the prop due to diameter / length and blunt leading edge and you would require a imco or speedmaster ??

Guessing a cat might go faster because of gear case riding to the top and a V would be lower in the water and not riding on top.

I know stock outboard gear cases sometimes blow out in the 80-85mph range because they are short for the diameter, if running and over the hub prop?

Just thought I'd see where the thresh hold is, before the ass comes around to meet the front-LOL

I shouldn't have a problem with current GPS 93mph Vee, it's doing it, but made me think, if I tried to do more.

What are others getting?

Thanks

JaayTeee

Back in 1990, when the current lower came out, merc literature stated that it was tested up to 95 MPH without any blowout...I've been low 90's with mine.

Black Baja

iTrader: (2)

My buddies 30' Specter cat goes 120mph with carb hp500's and stock b1's. He has never blown a drive but drive couplers only last about a season.

abones

It has been my experiance that there are a multitude of factors that either limit or add to the speed that a stock Bravo lower will begin to force the water away from the prop. Straight V, pad V, Notched V stepped V, staggered, etc, As far as a cat mostly the same, Notched, center pod etc, It is apparent that the depth of the bullet has to be different from hull to hull, and experimenting is the only way to find out what works for your application. I Also believe that the Propeller design is equally as important, I run a very high X with my Bravos, and a stock or labbed Bravo 1 just wont cut it, I had to bang my Bravo 1s to my spec,I have taken my stock drives to speeds in excess of 128 MPH, so it can be done just need a specialized set up including the prop.

r015

Thanks that's moving along pretty well, yes your right and your application is probably the most efficient due to the blue printing of lower and the case actually riding on top of the water. A good set up cat the gear case is riding on the water so a lot less chance of blowing out ,had 3 cats of my own at approx.125mph, but not with stock bravo's. Nice Job.

Boat I'm using now has a Pad V with transom step, just gives you better balance with less trim and can run the gear case higher and still get water to the prop, like having a set back.

Thanks, Guess the answer to me is, 100+ is most likely possible even with a Vee,if set up right.

SB

iTrader: (1)

Question, wouldn't a single Bravo blow-out at a lower speed than 2 ?

I'm thinking a single would have to be mounted a little deeper than dual, and that one prop can only grab and control so much.

Just a thought spoken out so I can hear others info and learn more.

GPM

I had one at 148 with a nose cone, didn't blow out. I think drive heigth and over trimming could be a big problem. A cat with the center pod lower than the outer sponsons is probably the worst.

ThisIsLivin

I am running 90 and added a nose cone and noticed improved stability at speed, of course that is on a Velocity with a pad bottom.

Relaxing

Get an Imco and go killer !!!!!!!!!!

r015

2 boats ago,put an imco -2 lower on, picked up 3 mph and better handling. Maybe could of been a little better with 5 blade, slip went from 15%-20%

Seen a Cig TG with Bravo 1 lowers claimed 105mph ? There's your goal Relaxing ,get those motors out.-LOL