My trip to Mercury's Lake X

[Donzi Blackhawk]

Well everyone, I had my trip planned and set off for something I will most likely get to do only once in my life. Guess what happened?! Everything went according to plan! What, were you expecting something bad? The trip to Lake X was not a bad ride. My Bronco has 177,000 on the clock and loves to drink fuel. (Spent more in gas for the Bronco than a full day of testing on the Blackhawk!) The Blackhawk was ready to rock! Here I am backed into their shop ready to set up the test equipment. http://donzi.net/photos/bniedospial201.jpg

The first run was a base line. 1.5:1 swinging a pair of 31's at 4950 rpm. Water was dead calm. Mark Albers took this photo for me. He decided to run the video for the fly by shots. All I can say is WOW after viewing the footage! http://donzi.net/photos/bniedospial202.jpg

Under the VERY watchful eye of Mark Albers, the guys from Mercury started switching props. Wide open throttle speed was important, but so is propeller slip. http://donzi.net/photos/bniedospial203.jpg

Bryant (Lake X certified)

[Capt. Donzi]

Dang Bryant, I just missed ya last week!
How much did you have to bribe Schoederer to get in there? :D
So what was you final speed??
Ok like you would post that here......but it was worth a try! :p

[Mark Albers]

Capt Spectra wink

When Steve Schoderer (Mercury Production Application Engineer) saw the Black Hawk all bets were off

You shoud see the video !!!
Especially all the top secret stuff :D

Mark 311 :cool:
Sarasota - - - W F O (close to the factory and far from a dream)

[Donzi Blackhawk]

Ok, let's keep going shall we? Since Mark was not feeling too well early in the morning, I knew a trip to see Dr. Lake would do him some good. Next the Mercury boys broke out the big guns. All that they said to me was "See if you can pull these!" http://donzi.net/photos/bniedospial204.jpg

Well! Holy crap! check those props out. The fwd prop is a 31 four blade and the aft prop is a 33 five blade. I launched the boat and fired her up. Just over the rumble of the exhaust I heard "I think I can" from the engine compartment. Same 1.5:1 ratio drive, but this time was only able to pull 4650-4700 rpm. The boat seemed to behave a little better while still running the bow high.

Some people complain that the Blackhawk bow rides too high. Well what do you expect when at speed the boat sits back on its rocker. The boat is doing what is supposed to do. Very little wetted surface. Through all of my testing have I nver found the boat to chine walk, bow steer or track other than like it is on rails. This is a very smooth boat at speed. I must note at this time that I am running a higher X dimension than all of the other Blackhawks that left the factory.

We put the boat back on the trailer and decide to swap gear ratios. Here we are changing out one of their Blackhawk gearcases. http://donzi.net/photos/bniedospial205.jpg

Hey CDMA this new gear ratio is from their top secret closet. Man, I bet you are trying to run the math in your head right now! Here is a shot of the ramp for trailered boats. http://donzi.net/photos/bniedospial206.jpg


This last run I was running back up to 4900 rpm. This is fine running in fresh water. Should prove to be even faster in salt water with the one foot chop this boat loves to run in. While speed was important, The boat ran between 73 and 79 throughout the day. Remember, this is fresh water, dead calm with air temp in the high 80's to low 90's. All this out of a 454 Mag MPI! Hey CDMA, can you guess my hp?

Bryant (Been to Lake X)

[Donzi Blackhawk]

Just on more thing. I now have the gear ratios and the props to actually allow me to calculate what I need to do to put together a serious engine. Looks like I just might get into the "fastest 22" club after all.

I hope not too many people were upset with the limited number of photos taken of the trip. Mercury was very specific about what we were allowed to photograph. I tip my hat to the people at Lake X, they treated us very well! The shop was very organized.

Thanks to Mark Albers, he ran the video, rode shotgun to and from, but more importantly, did NOT bitch when we skipped lunch to keep testing. By the time we got back to Sarasota, I had a hunger headache that would bring tears to your eyes. Mark, I hope the trip to Dr. Lake made you feel better. eek!


One last thing, the decal on the back of my boat "Dialed in at Lake X", has now officially been validated!!!!! Yah!! :D

Bryant (I have been X'ed) Hey Jerry is this right?

[CDMA]

Bryant,

Looks awesome. 80 mph (in the right conditions) with a 454. Won't take much to get you with the big boys.

Give me a call at home.

Chris

[Tomahawk]

Bryant - really enjoying this thread. Very trick prop arrangement! Too bad you can't make Eufaula V Labor Day weekend. You'd be right in the hunt. Thanks for the story and pics.

[blackhawk]

Bryant, did you up running a 1.65 with the 4 and 5 blade cleavers?

I tried that combo on my boat and it worked awesome in calm water or with some decent chop but in the "slop" the boat was a handful!

[Donzi Blackhawk]

Here are a few shots of the props. Looks as if I might be able to a little side work for Julia Child, or was it Ron Popeale, can't remember now. http://donzi.net/photos/bniedospial208.jpg

Another http://donzi.net/photos/bniedospial209.jpg

And yet another http://donzi.net/photos/bniedospial210.jpg

I bet they wont like me in the Manatee speed zones now!

Bryant

[boldts]

Bryant, your trip to Lake-X has been a best seller on my have to read list. I like probably many others have only read and seen the recent commercial about Mercury's long lost test lake. Now, since you guys did the trip in one day, I can now assume that the lake is at least in Florida somewhere. How many board members are estimating the distance from the white bottom color to the top of your BlackHawk for that X dimension and hoping Donzi hasn't changed the dimensions of their hull color thru the years? With that 5 blade on the drive, you've got quite a blender back there. Interesting that a left hand outside prop makes a difference in the performance. Like Poodle said, you have counter rotating props, why would it matter which way the last prop is turning?

Thank-you and Mark for the wonderful pictures and a great story. Any chance we'll get the video posted here also? :D

[Bad-Tat]

Bryant,
Is 4900 the optimum rpm for your motor? My 502 does 5200 with the 31s which is where the book says it's supposed to be. Are those one off props or is Merc going to make them available?
Thanks,

[CDMA]

GASP...is that dirt I see on Bryant's boat???

Chris

No way as clean as that machine

[Donzi Blackhawk]

Chris,

You had me worried, I ran out with all of my cleaning supplies only to find a spotless boat. Would you expect anything less? Checked out camera lens - yep, dirty! Now that is also clean!

Scott,

The gear ratio is top secret, they pulled this one off the shelf and installed it into the gearcase for me to test.

Bill,

The rev limiter on my engine kicks in at 5050. If I run trimmed out with a huge rooster tail it will run at 5000 all day long. Trim in just a bit and I can feel the boat pick up speed. Remember the water all day long was dead calm. Blackhawks like a one foot chop to help break the wetted surface. Those props are one of a kind. By slowing down the propshaft speed while increasing the rake and playing with the prop diameter, a noticable reduction in propeller slip is realized.

Bryant (The directions to Lake X just went up in smoke)

[Rootsy]

yep yep... 14 3/4 quad IV O/T hydromotive... 33% @ 3500... 17% @ 5500....

swap to the larger diameter quad IV... 8 - 9% across the board... but you just cannot pull the same rpm or speed...

what to do what to do... to keep the midrange and gain the top end....

Rootsy - mr oddball gear ratio (1.59)

[blackhawk]

Bryant, I'll bet you I know what the ratio is, but I will keep my mouth(or should I say fingers) shut on the board for ya! Good luck with them and let me know how you handle in the "slop". With your higher X dimension they make work better for you. Like I said, they will definitely gather a crowd quick when she's on the trailer.

Bill, my motor has a Maximum WOT RPM of 4600-5000. I usually run mine about 4800 in optimal conditions. It's actually just as fast trimmed in at 4800 and handles better. Less stress on the props and gimbal when you're not trimmed out throwing a big roost too.

[Donzi Blackhawk]

Check out these cut Blackhawk props. 31 pitch modified to reduce bow lift. http://donzi.net/photos/bniedospial211.jpg


Bill,

I'm not sure what year your engine is but my books show all 502's to have a wide open throttle range of 4600 - 5000 rpm. This is what my engine follows with the rev limmiter kicking in at 5050 rpm. Check out the information decal on your engine.

Bryant (Have props and I'm not afraid to use them)

[Bad-Tat]

My book and decals say 5200 for this 96 502. I usually leave the drive level. Just raise the tabs and go for it.

[blackhawk]

Bryant, those are some wicked looking ears on those modified props! Did you try them?