LiveWire

If you have or had or know about BMax drives I would like to know the best gear ratio for them. I have a pair of Innovation Marine 650HP with Warlock ext. boxes and BMax drives with a 1.4.3:1 ratio. I am spinning lab 28P Bravos. I would like to get more speed out of this setup. Let the comments begin!!!

Strip Poker 388

iTrader: (6)

I beleave he only makes 1.11, 1.19, and 1.30.

I have the 1.30 B-Max's and turned a 28 Bravo 4bl at 6100 last year.
This year I am waiting on the new HT's with the creasent lowers .I Have a 100 more HP each motor hoping to turn the new 30's 6000.

You should be good at the 28 at 1.30 gear.depends what RPM ya at.


Rob


http://bravoshop.com/index.html


.

Heres some picks of the first design drives insides

LiveWire

Rob,

I'm spinning the 28's about 5400 with the 1.43 gear ratio. Dean at BMax said I should change them to the 1.30 ratio. I believe 5600/5800 I start to bounce off the limiter.

Strip Poker 388

iTrader: (6)

If you can only turn 5400 now Your going the wrong way with gear ratio.I didnt know Dean made a 1.43? You might take your 28 and make this 27 to get a few hunderd RPM more to get you close to peak HP.

Depends on your Peak HP though.What is it?????????

Like on mine it wasent making a hole lot more power above 6000 like 5-10 hp per 100 RPM,so I try to proped it to turn around 6000.

I was always told on the BRAVO ONE props the closer you can run to 30 pt 4 blade the more efeciaent it is [faster]. Like my boat came with 30's and a 1.50 and the 1.36 w/ 26's was slower at the same RPM.Also and thats what Hustler even told me.Bret at B Blades says the same thing.

LiveWire

I have twin Innovation Marine 650HP for power. I tried 26P Bravo 4 blades and was bouncing off the limiter. I also, tried 30P Bravo 4 blades and couldn't get them passed 4800rpm. I know I am missing something but not sure what it is? Is it props, gear ratio or should I just change out the BMax drives for something else? I would like to keep the rigging set up the way it is and try to find the magic combination of prop, gear ratio and rpm for the best top end. She has great mid-range power at the current set up. Maybe I have the rpm wrong but I'm pretty sure Innovation told me to keep WOT at 5400 but it could be 5600. I believe the dyno tests they sent me they had them over 6000-6600rpm. I'll have to go dig up the paperwork and double check my prop test notes - but I know I can do better than what I am now. Keep the advice coming!!!

zt260

The only down side to the 1.43 is the durability. They fail quite a bit, that’s why dean dropped them. Actually the 1.43 uses the 1.65 lower gears from mercury. The pinion gear is very small and strips off teeth. I have the 1.30, and would rather have the 1.43 if it was durable. But I’ve already broke several lowers. If you’re not breaking them, I doubt you will gain anything with the 1.30, and most likely you will lose speed.

I would consider shorty drives. What’s your slip like? How far below the hull are your propshafts? I gained 7mph with a shorty and a labbed maximus.

articfriends

iTrader: (1)

If your motor builder told you to keep wot at 5400 and your turning 5400 then unless your hp peak is actually higher you will only be throwing money away re-gearing as your already where your supposed to be. Maybe a set of 30 pitch labbed props would net you a few mph but will probably drop you to 5200 and go same speed. Find out your actually hp peak and post it so we can try to help more,Smitty

Strip Poker 388

iTrader: (6)

Like they said we need peek HP at what RPM?????????from the #'s its sounds like your close .

Also what hull is it?

I know that Innovation likes building bigger cubic inch motors so I bet you have a lot of TQ and your RPM is prob close to the 5400-5600,I would think they will be conservitive on the RPM.

LiveWire

Thanks guys for the continued input. I verified that the peak HP is 650 and torque is 600+ 625max. The boat (Hull) is a 2002 Donzi 38 Daytona. I run consistantly 83-84mph in glass to 1ft chop with a full tank and 2 to 6 people with gear. When I was in the Gulf she ran 87-89mph with a full tank and 4 guys in the intercoastal - water was like glass. When we went out in open water it was windy and had 4 to 6 footers and was at half a tank with the 4 guys and ran 95mph. I know you always run faster in salt than fresh water but I want to get her running faster in fresh water without having to change/modify the power for durability reasons. I don't mind tweaking with the props and drives to obtain peak fresh water performance but I also, don't want to sacrifice durability either. I so far have had good luck with the gear ratio at the 1.43 - Only one snapped lower shaft - it was clean. Not a twist or anything. I chaulked it up as a defective shaft. In my BMax versions (Dean) used Mercury parts and shafts. He also, commented for durabilty reasons to change to the 1.30 ratio but, if it hasn't caused a problem then leave it alone. I still need to verify WOT RPM and rev limiter RPM. So with this new info what do you guys think I should do?

zt260

Play with drive height and props. Gearing isn't the answer IMO.