Performance Boats Forum banner

1 - 20 of 23 Posts

·
Premium Member
Joined
·
96 Posts
Discussion Starter #1
Looking at a 1994 24' Eliminator Daytona listed with the following; a 1997 Mercruiser 502 EFI, Mercury High Perfoormance Gimbal housing, Bravo shop Black Hawk out drive and 1:36 gears.
I dont much of any thing about this style of out drive. Can some one edjucate me as far as what it is, reliability, availability, etc... prop compatibility. Is this something that is considered an "upgrade" or an "avoid"
 

·
Registered
Joined
·
2,234 Posts
Looking at a 1994 24' Eliminator Daytona listed with the following; a 1997 Mercruiser 502 EFI, Mercury High Perfoormance Gimbal housing, Bravo shop Black Hawk out drive and 1:36 gears.
I dont much of any thing about this style of out drive. Can some one edjucate me as far as what it is, reliability, availability, etc... prop compatibility. Is this something that is considered an "upgrade" or an "avoid"

Biggest problem IMHO, it is a discontinued unit...

They work pretty well, but never really took off and never got really refined.

being a surface piercing deal, they have some limitations, they also make a buttload of spray, not really a rooster tail, just a bizarre spray...

Very fun to drive and look at, I have one in my shed, bought it because I wanted to build a little rocket ship, but never got there, the props are pretty hard to find too....
 

·
Premium Member
Joined
·
96 Posts
Discussion Starter #3
Did a search through the forums here and found some more info, looks like parts and props would be a real problem not sure its for me
Looks like they were designed more for the 22 daytona, the 24' might be a little heavy.
 

·
Registered
Joined
·
14 Posts
i had one on a 22 eliminator daytona. i will say that I eventually went to a bravo. there is a signifigant top speed difference, but the other trade off were not worth it imo. pm me for details
 

·
Floatin dirty
Joined
·
4,831 Posts
Did a search through the forums here and found some more info, looks like parts and props would be a real problem not sure its for me
Looks like they were designed more for the 22 daytona, the 24' might be a little heavy.

Depends if your boat was built with the blackhawk in mind. They incorporate a notch in the transom just for the blackhawk drive. This may require some mods if you switch to standard bravo in the future but it can work. Will have to play with the X dimension a little. I had a 22 with a blackhawk and thought it was a great set up but there are trade offs such as planing time and available parts.
 

·
Registered
Joined
·
386 Posts
For what it's worth, I'd avoid buying anything with a used Black Hawk. The concept was good, but the application turned out to be very limited, and now replacement parts and props are becoming increasingly scarce. On the plus side, the Black Hawk was more efficient (faster) on the top end than a stock Bravo, and delivered more stability thanks to the counter-rotating props on a single propshaft. It was very weak, however, when it came to shifting (most Black Hawk owners finally just left the drive in forward gear and never used neutral or reverse). It also had a very fast idle speed (800 to 1000 rpm was 10-15 mph) -- not good for marinas and no-wake zones. On plane acceleration was poor and you had to be very tender with the rpms in a turn otherwise the drive tended to break. Just wasn't a propulsion system that fit recreational boaters. Mercury finally put a bullet in the project after spending a large sum of money in its development.
 

·
Floatin dirty
Joined
·
4,831 Posts
I do agree with most of your points. The drive only worked on certain applications. I never had to leave mine in gear but would have to shift back and forth between neutral and forward a lot due to fast idle speed. If you did not have an EFI motor, the drive would stall with carbs. Planing time sucked unless you were running the smallest props which were 27". Mid range and top end was great but more important, was the fuel efficency with the drive. With only 60 pounds of drag in the water, my 22 got great fuel economy and I drove 80 plus everwhere in that little boat. I think a nice 550-600 EFI motor would be a good set up in a 22 to 25' Daytona with a blackhawk drive even given the trade offs you mentioned.
 

·
Frozen Hoser
Joined
·
118 Posts
I would certainly argue the "weak" part about BH drives. I pounded 160 hrs on mine with 575 hp in a 25 Daytona and never broke it. Used to snap teeth of bravo x drives every 20 to 30 hrs in our big sloppy water.
Planing in a heavier boat is very hard on the drive. That can be fixed by adding an airation system to the BH. The original design had the exhaust going thru the drive and spilling infront of the props to break them loose.
After designing and fabricating an internal airation system, my 25 would plane out rather easily. It also slowed the idle speed to about 9mph which sure made loading and docking easier.
As for the benefits, 8.3 bolt on mph, 15% better fuel economy, dead straight tracking.
I only wish the drive was strong enough for my new blower motor because it would still be on my boat. I went up 325 hp and 300 lb ft but only gained 16mph because of drive drag with a scx / sc shortie combo.

I even considered using two BH drives and a splitter box but too much stringer was in the way to put a drive in each sponson. Too bad, that would have been a hell of a package.
 

·
Floatin dirty
Joined
·
4,831 Posts
Can you give us more details about this internal airation system you came up with? Sounds very interesting, I know with maximus props, you can pop out a few of those plastic caps which allows the prop to airate better and improves planing.
 

·
Frozen Hoser
Joined
·
118 Posts
sure.
I fabbed it up using an 18" piece of 1.5" diameter, thick walled aluminum tube, some 1" x 1/8" stainless flat bar and my drive shower cap.
Under the rear cover of the BH drive is a long recessed area. Using epoxy
putty to build a little wall at approximately the half way point from the rear of the recessed area, you subdivide the space in the recess. The new little wall needs to align with the crossways reinforcement rib on the underside of the rear cover. I drilled 16 1/2" holes thru the bottom of the newly formed rear section thru the cavitation plate to above the props. I cut a hole in the rear cover to accept the aluminum tube and welded it in place. Next was to use some good RTV and form a seal around the rear compartment and when dry, reinstall the rear cover with the aluminum tube mounted above all the holes. Using the ss flatbar, I fabbed up a long support bracket which attaches to the shower cap on the sides and wraps around the tube.It is secured to the aluminum tube with three ss bolts.
A little jb weld where the tube is welded(from the bottom) to thetop side of the rear cover, some sanding to fair the JB weld, painting and polishing and you have a nice, strong and shiny airation tube. It allows the props to suck air thru the "cavitation plate" as per say.
Makes a nice water fountain in reverse too :)

ps, a blue plastic shipping cap for PVC pipe makes a good storage cover to keep debris out of the tube.
 

·
Frozen Hoser
Joined
·
118 Posts
Man seems like alot of work just put some tunnel tabs on and call it a day!
Probably about three hours total time invested and 20 bucks in materials. The planing issue swinging 31,s is getting the engine above 3 grand to make some torque, not getting the cats azz out of the hole. You could firewall the thing and the prop load would hold the motor around 2500 for a long time until you built some foreward speed. With the airator, planing time was cut by 2/3 using alot less throttle. Well worth the investment.
 

·
Floatin dirty
Joined
·
4,831 Posts
Wow, that is quite a concept you came up with. Is this similar to those airator systems (black tubes) sticking out of the #6 drives that some people use? Is that where you got your idea? Seems to have given you great results for a small dollar investment. :)devil
 

·
Frozen Hoser
Joined
·
118 Posts
ya, pretty much. I fabbed some airators up for a friend with a 32 active cat. He had 800 N/A's and number 5 drives with really tall props. It was a major pig out of the hole. Took about 30 seconds to plane off. 20 bucks worth of stainless and hose and less than 10 seconds to roll over. I figured if it worked for him, it would work for me. I just wanted a finnished product that looked nice and not cobbled together. I prefer polished stainless and aluminum to rubber and hose clamps :)
 

·
Registered
Joined
·
317 Posts
i have a 95 22 daytona black hawk with dyno 560hp 630ftlb i just got 29 an 31 for an bob leach showed my an airated BH he has down at eliminator so would it be good to do this to my BH extreme custom marine has the boat right now i just have issue with planing with fuel an a 3 pasengers an thats with 27
 

·
Frozen Hoser
Joined
·
118 Posts
i have a 95 22 daytona black hawk with dyno 560hp 630ftlb i just got 29 an 31 for an bob leach showed my an airated BH he has down at eliminator so would it be good to do this to my BH extreme custom marine has the boat right now i just have issue with planing with fuel an a 3 pasengers an thats with 27
Well, if it struggles to build rpm now, its only going to be worse with the taller props. It sure was worth it on my 25. No question. With 4 adults and full tanks, it wouldn't plane. Period. after airating it, it would plane with 5 and full tanks.
 

·
Registered
Joined
·
317 Posts
well i am allways careful how i load the drive trying to plane i just run it up to 2000rpm an just wait for it to roll over with the higher hp i dont want to go wot it runs up to 2k prety good i was thinking of trying tabs right now i cav the 27s real easy the prop place said i have 20% prop slip with higher rpm it slower with the more hp
 

·
Registered
Joined
·
317 Posts
an do u have any pics of your BH i would like to see how u did it the on at eliminator was tig welded an done by ther drive guy
 

·
Floatin dirty
Joined
·
4,831 Posts
ya, pretty much. I fabbed some airators up for a friend with a 32 active cat. He had 800 N/A's and number 5 drives with really tall props. It was a major pig out of the hole. Took about 30 seconds to plane off. 20 bucks worth of stainless and hose and less than 10 seconds to roll over. I figured if it worked for him, it would work for me. I just wanted a finnished product that looked nice and not cobbled together. I prefer polished stainless and aluminum to rubber and hose clamps :)

Wow, that is quite an improvement. Good info for those that plan on using those type of drives.
 

·
Frozen Hoser
Joined
·
118 Posts
an do u have any pics of your BH i would like to see how u did it the on at eliminator was tig welded an done by ther drive guy
Nothing handy but I am picking up my BH from my drive guy this weekend. I had it freshened for the next owner, who ever that may be :)

I will snap some pics and post them next week.
 
1 - 20 of 23 Posts
Top