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evetsathom
11-06-2003, 07:33 PM
I purchased the boat (96 22' 502mpi w/ blackhawk drive with 31 wheels)earlier this summer. With the rain and a heavy work schedule I have not had much time to spend on it. The first several trips were pretty much consomed by learning how to trim the boat at various speeds and sea conditions. This weekend was the first time I really stood on it. It topped out at 72 mph (via gps)@ 4200 rpm. I thought these boats were suppose to turn more then that.
The boat was just back from the shop (capable merch mechanic)with a clean bill of health.
I did note a very small ding on the rear wheel when I pulled it out. Could that be the problem? What should the top rpm / mph be on this thing?

DAULEY
11-06-2003, 07:43 PM
were you trimed all the way ? what were the water cond ect. my 95 with blackhawk drive on iton a good day water like glass 82.66 at 5100 rpms i changed the drive to bravo and spinning a bravo 1 4 blade at 4900 rpms boat is running about 74+
something doesnt sound right

Bad-Tat
11-06-2003, 07:57 PM
You should be getting at least 4900 and 78.5 without even trying hard with the 31's. Better to have at least 1' chop for that. I leave my drive straight as trying to trim it up blows out the props. I just walk the tabs up slowly and it just keeps raising up out of the water and flys. Takes a lot of lake but great fun.

FABIO
11-07-2003, 04:36 PM
I also purchased a Blackhawk earlier this year and my performance figures were almost identical (72 on GPS @ 4200rpm). I had my props (31's) labbed. The times that I have seen 72 mph have all been on smooth water, playing with the tabs trying to "dial it in just right". I had a small exhaust leak originally, and was only getting around 3200 rpm's....after somewhat fixing the leak (I notice that it is still slightly leaking)I was able to consistantly get 4200, but no more. I'm going to install IMCO Powerflow manifolds shortly and hope this will bring me to full rpm. (Will also fix leak at that time)

BigGrizzly
11-07-2003, 05:41 PM
Guys , the problem is that the drive is too low X demention on the hull. Your drives are in std location for a bravo. The blachHawk only works well aired our. Your only option at this point is a set of 29's/ the other potipn is only drive in 1 to 2 foot chop.

Greg Maier
11-07-2003, 05:59 PM
I don't know about Fabio's boat but I thought that Evetsathom's Blackhawk had the Blackhawk Hull.

Big Grizzly, are you saying that the Blackhawk Hull has the X-dim too low or that a standard 22 has the X-dim too low?

Fabio, have you considered Stainless Marine Exhaust? Stainless Marine exhaust doesn't pass the cooling water through the flange between the manifold and pipe. Instead, Stainless Marine systems route the water through a hose to transfer it from the manifold to the pipe. Most consider this to be a better design.

BigGrizzly
11-08-2003, 07:37 AM
The classic X is too low. In this case actually the design engineer that designed the drive actually said that the X demention of the Blackhawh Donzi was too low also, this is a fact. With the speed and RPMs of Everet"s is the same that Vaughn's motor turned. On his worst day Batman's turned better than that totally stock beforehe learned hoe to drive it. Of corse it could be a 454 with the dress up kit. I know there are at least 2 besdes Bryants X boat that had the engines swapped and have 454'S

Greg Maier
11-08-2003, 11:53 AM
Randy,

The X-dim in the Blackhawk definitely was a compromise. Donzi raised the engine as high as they could without putting on a bubble hatch on the Blackhawk. The underside of my hatch actually has indentations in it from parts of the engine that make contact when the hatch is closed.

Dr. Dan
11-08-2003, 12:27 PM
:D You guys are all correct, Chris,Woodsy and Stevie Marr can confirm....when looking at Steve's screaming X-18....he has the correct X Dimension for that Blackhawk drive and that sucker is higher than you can imagine, hence his seriously custom hemi hood scoop hatch....but as anyone who has seen or driven that X-18...it moves right along...great times this year at 1000 Islands! :p

Doc