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Donziweasel
10-12-2013, 10:32 AM
Nevermind.

Morgan's Cloud
10-12-2013, 12:27 PM
Have you seen/read any of my posts on my B3 and Volvo dp experiences ?
I hate internet echo .

Donziweasel
10-12-2013, 06:58 PM
I haven't been around much the last few years, so I must have missed it. I will delete this thread if you like.

Carl C
10-13-2013, 06:53 AM
There will always be "internet echo" and usually some fresh input and opinions. Some links might have been helpful. How many times have oil and prop threads come up? I usually learn something new each time; Or at least confirm that I'm doing it right....... :alligator

Morgan's Cloud
10-13-2013, 08:03 AM
No, seriously I don't mind re-stating as long as it doesn't sound like a broken record to some people.

First off, Tony has the 22C , now for sale , that was rigged with a 385 DPX package from the factory. He has waxed eloquently about it's handling often. Actually , I'd love to know if he's also driven a MAG B1 package so he can make the direct comparison.

In my case we re-powered the Magnum with a 502 B3 package but because it was a basket case when we got it , we had never driven it before so we don't have a basis for a before and after comparison. My belief that it handles extraordinarily well was confirmed when our mechanic went nuts over it's performance. As a former racer and builder and ace mechanic who's driven everything I take that as a fair testimonial.

When the restoration on the St T was finished I dropped in a new Volvo 5.7 package with the new single prop SX-A unit. This would be Volvo's version of the 350MAG / B1 unit.
To my horror the boat was virtually undriveable. Randy sent me a prop that he thought would settle things down but it made no difference at all.
I ended up biting the bullet and switched the unit out for a DPS-A.
The difference was like night and day . Just unbelievable .

Now , a lot of people will say that the B3 isn't as fast as a B1 but it's probably not a fair comparison to bring Volvo into it. The DPX and DPS-A units are hydrodynamically faster than the B units.

If you're toying with the idea of going dp on your new project please let me know and I'll gladly expand on my opinion .

joseph m. hahnl
10-13-2013, 09:05 AM
I think you need to look at what the deign intent is. No I haven't personally talked to the engineer and I have no real word experience with twin props . So if I was to guess, they are for weight, heavy boats that need big pitch to go fast and a little pitch that would give it a prayer of getting on plane. Now you put it in a light 2400 LBS boat with mega pitch, prop torque listing:boggled: seems eminent :hangum:, The questions that comes to my mind does the short pitched slipper prop ,slip the other larger prop so it actually has a greater slip % then a stand alone prop, canceling list.:crossfing: How much can the pitch variable be between props, and what are the sizes available. For example if the max pitch was a 27p.it would be more cost effective to get the motor to turn a single.:wink: But in all honesty it would look BBBBBBad to the Bone:worthy:

Morgan's Cloud
10-13-2013, 09:20 AM
Joe, I was so amazed at the transformation in my St Tropez that in a post a while back I said that maybe the dp unit is even more beneficial for our small fast boats than originally thought.

There is NO prop torque effect whatsoever. When you jab the throttle from an in gear idle the boat does not (like it used to do) torque over to the port side .It just lunges forward perfectly level.
Chine walking ? A thing of the past ! Turns to port or starboard ? No preferential side , they're both the same.
And that annoying deep V trait of 'hunting' ... also a thing of the past.

Volvo does not reveal the sizes of their props by the way they list/sell them .They just have a number/letter combo that once you understand it means that the greater the number the higher the pitch .You just don't know what the pitch is.
I had mine scanned and I can confirm that an 'F7' set is 26'' . With Mercs they tell you the size. Interestingly , the Magnum also utilizes a 26' prop set .

There is no doubt in my mind that the St T is actually faster now with the DPS-A unit. The only question is, is that because it IS faster , or because of it's massive improvement in handling I can now explore top speeds for a bit longer ?

Greg Guimond
10-13-2013, 09:34 AM
If your objective Donziweasel is top speed then B1, if your goal is to have the best all around package for handling then B3. West coast guys run the B3's all the time and love 'em. There wive's love 'em even more as they are easy to drive as has been described in detail above. My .02 is I'd just buy Tony's 22 Classic and cut the 18 loose.

mattyboy
10-13-2013, 09:37 AM
MC

some interesting tests

http://www.youtube.com/watch?v=JZp_HODU104



http://www.youtube.com/watch?v=eSCJ89lczug

http://www.youtube.com/watch?v=CAk2Q20HkvY

joseph m. hahnl
10-13-2013, 09:37 AM
Joe, I was so amazed at the transformation in my St Tropez that in a post a while back I said that maybe the dp unit is even more beneficial for our small fast boats than originally thought.

There is NO prop torque effect whatsoever. When you jab the throttle from an in gear idle the boat does not (like it used to do) torque over to the port side .It just lunges forward perfectly level.
Chine walking ? A thing of the past ! Turns to port or starboard ? No preferential side , they're both the same.
And that annoying deep V trait of 'hunting' ... also a thing of the past.

Volvo does not reveal the sizes of their props by the way they list/sell them .They just have a number/letter combo that once you understand it means that the greater the number the higher the pitch .You just don't know what the pitch is.
I had mine scanned and I can confirm that an 'F7' set is 26'' . With Mercs they tell you the size. Interestingly , the Magnum also utilizes a 26' prop set .

There is no doubt in my mind that the St T is actually faster now with the DPS-A unit. The only question is, is that because it IS faster , or because of it's massive improvement in handling I can now explore top speeds for a bit longer ? 26P with a stock 350? It would be faster:biggrin:. You should plug it into a prop calculator and get the slip% to compare to a stand alone.:party:

mattyboy
10-13-2013, 09:55 AM
Joe

the duo props run higher ratios then V8 singles 1.9 2 2.14

and when you get the slip number divide by 2


just an example in one of the test films i posted the regal 27 at 6000 rpm 54 mph and a 2.14 with 26 pitch set is at about 21% slip or 10 percent on each prop. if i remember correctly the BH ran around the same slip %

would love to see what a lighter boat that is stern weight sensitive to begin with reacts to the light weight power

Morgan's Cloud
10-13-2013, 10:08 AM
The 380 is a very interesting engine package . It will be interesting to see what Volvo's lineup looks like when it is fitted in . I can understand it's influence on the 8.1 , 8.2 engines but if it's weight is as good or better than the 350's it'll be interesting to see what becomes of them too.

I never knew how to do the prop slip calculator thingy with a dp and I've never seen a site that offers the option to do a dp calculation , but Matty is right about the gearing differences.

The Mag is running a 2.0:1 ratio and the Donzi is running a 1.95:1 ratio.

If I was doing a dp installation on another smaller boat again and wanted max performance I would go with the Volvo over the B3.

Out here service is a nightmare and parts are ridiculously expensive and you have to wait for them no matter what colour your engine is. Understandably , things are a little different in the US and that has a huge effect on one's decision .

joseph m. hahnl
10-13-2013, 10:14 AM
Joe

the duo props run higher ratios then V8 singles 1.9 2 2.14

and when you get the slip number divide by 2


just an example in one of the test films i posted the regal 27 at 6000 rpm 54 mph and a 2.14 with 26 pitch set is at about 21% slip or 10 percent on each prop. if i remember correctly the BH ran around the same slip %

would love to see what a lighter boat that is stern weight sensitive to begin with reacts to the light weight power

http://drawception.com/pub/panels/2012/7-12/tt4LR8PAXW-2.png

mattyboy
10-13-2013, 10:18 AM
MC

I guess it is a mathematical equation that gives one an idea of how efficient the prop/s are. I always wondered how they figure for hull weight and design?????

the way I look at it a prop must have some slip a good prop is around 10% or under so when there are two pushing the same way their slip is combined ,either on one shaft or two shafts in a twin app.

Morgan's Cloud
10-13-2013, 10:22 AM
I keep forgetting to bring this up .

Jim , a member with a lot of experience under his belt has a Yammy dp on his OB16
I know he's driven more than his share of boats plus he has what must be the only dp 16OB around .

It would be great to hear his experience as well .

One thing that does put me in a rather unusual situation is that I converted the same boat and engine package to a dp after running it as a singe prop unit .
So it's a true apples to apples comparison.
Not like boat tests that have run 'similar' drive packages , one Merc ,one Volvo, on the same model of boat. Just a few small inconsistencies in the build difference of the two boats alone could affect results and impressions .

edit: Matty , in my opinion it looks like Volvo has put in a lot more time/research into their dp props than Merc. There's a big difference in appearance between the two sets I run and they're both 26'' sets. That could have an effect on the end result too .

mattyboy
10-13-2013, 10:28 AM
MC

here is the VP 2014 line up they have a new 430 hp 6 liter motor and offer a vp350 a 350 ci 350 hp motor all look to have a 6000 rpm service limit .

wonder if i can get my letter to Santa back ????

a VP430 :yes:

http://www.volvopenta.com/volvopenta/global/en-gb/marine_leisure_engines/Aquamatic/c_gasoline_sterndrive/Pages/V8-430.aspx

BUIZILLA
10-13-2013, 10:58 AM
I can drive my 16ob with the dp for a couple hundred miles at a time, and never get tired of wheel steer torque, it's a one finger setup... I did a nonstop 115.2 miles in 2.25 hours yesterday, avg. 52 mph cruise speed, effortless, this boat has been 110% reliable

I became a 100% believer after having my 252BR Formula with the BIII, I think it was a 2.0 ratio, and I ended up with 26" front and 28" rear props turning 4650-4700 WOT

if I have the time and energy, the deckboat is going to get a BIII over the winter

i'm THAT sold on the setup

i'd like to do a St Tropez resto with a BIII and a fwc 383, that's on the bucket list

Greg Guimond
10-13-2013, 10:59 AM
I keep forgetting to bring this up. Jim , a member with a lot of experience under his belt has a Yammy dp on his OB16
I know he's driven more than his share of boats plus he has what must be the only dp 16OB around. It would be great to hear his experience as well .


Jim will chime in but the Yammy TRP provides the same "ride on rails" handling as the B3. Again, it is not the fastest OB lower unit like a Sporty, but that is not what it is intended for.

Greg Guimond
10-13-2013, 11:26 AM
I can drive my 16ob with the dual prop for a couple hundred miles at a time, and never get tired of wheel steer torque, it's a one finger setup... I did a nonstop 115.2 miles in 2.25 hours yesterday, avg. 52 mph cruise speed, effortless.


I did 200 miles in my 16 Baby a few weeks ago. In my case I have a Sportmaster lower unit with the factory torque tab and Sea Star Pro steering which has been properly balanced with a "power bleeder". While it is not much effort to run it, it IS NOT the zero effort that Jim describes above with his sweet dual prop. Dual Prop is almost truly power steering. It would be very interesting to see Jim put bigger ponies on top and see the TRP react. I think he runs a 150hp carb.

Carl C
10-13-2013, 12:44 PM
Duoprops better run straight; They were originally used on torpedoes.

Morgan's Cloud
10-13-2013, 01:10 PM
Duoprops better run straight; They were originally used on torpedoes.

I wonder if they knew right off the bat that they'd have to be d/p's ? ?
Actually, running straight is only part of the picture in a pleasure boat application.
The boat just does not torque left or right due to prop rotation .

Jim , as you are ,I too am completely sold on the dp's now . If someone still says that single prop B1's are the performance package and dp's are for heavy cruisers I will invite them to get a plane ticket and come over here to try both of mine out .
There's a huge difference in weight and hull design between both boats but they still both feel very much 'high performance' .

Now, here's a question for you . In running your 16OB do you feel that you still have the same effective (positive) trim range as a single prop set up ?

BUIZILLA
10-13-2013, 02:51 PM
Now, here's a question for you . In running your 16OB do you feel that you still have the same effective (positive) trim range as a single prop set up ? LOL... right now it's 2" higher than a normal sp would be and I can easily go another 1/2, maybe 3/4"... I can trim to the moon right now..... I don't run it any higher now because dock manners at that height make it VERY sluggish response.....

interesting tidbit > one day I decided to remove the rear prop without lowering the engine, and it wouldn't hardly get on a plane, took several hundred feet more than normal, and revved over 5000 until it finally hooked, it lost 8 mph while picking up only 200 rpm, porpoised and chine walked like crazy, and generally handled like doo doo, put the rear prop back on and all is right with the world again...

Morgan's Cloud
10-13-2013, 03:13 PM
Well ,that was an interesting tidbit. I've always wondered what one of mine would run like if I removed the rear prop but you've saved me a lot of time :D

The reason I was curious about the pos trim , and I didn't want to set you up for a right or wrong response , was because what I've experienced to date is that I have less + trim than a single prop unit before the props begin to ventilate. In both cases I have the anti ventilation plate about an inch and an eighth above 'normal'.


Note to DW .. I hope this is the kind of feedback you were looking for . I've got plenty to say , I just don't want to sound like I'm repeating myself to others who may have seen my posts on the subject before.
There's only a couple of us here with real dp experience and when the chance comes up to discuss it I will jump at it , but some might say ' oh , not again ' :doh:

Now , what exactly was it that prompted you in the first place ? You don't have a bee in your bonnet , do you ?

roadtrip se
10-14-2013, 11:57 AM
DW posted this question on the other forum. I responded that Phil and Neil had put together a pretty nice 496HO 20 Cig with a B3. Seemed to run out pretty decent.

I am a fan of the B3 from running Formula SS boats, a 28 and a 37. I still have the 37, and it surprises folks with what it can do performance-wise
and maneuverability. It still surprises me, some times. But what I find interesting is that when Formula goes to a blue motor package for performance, their latest rigs in the 37 and 40 SS run B1 XRs, not B3s. And Formula rigs almost all of their boats with B3s these days.

There are a lot of choices today with B3 props in three and four blade combos, regular and XR flavor. I'll be honest, and say I haven't messed with them, because I'm happy with what the twin three blade, B3 X is doing on the boat, bone stock.

Based on what Formula is doing, and they should know, the old rules still apply... B3 for torque and handling, B1 for top end. Pick your poison.

Morgan's Cloud
10-14-2013, 05:39 PM
Based on what Formula is doing, and they should know, the old rules still apply... B3 for torque and handling, B1 for top end. Pick your poison.

Like I said earlier , (IMO) this applies for a black on black comparison but the new generation of Volvo DP units are 'higher performance' than the B3 and maybe even B1 units.

Just someone's opinion who has one of each . :)

Greg Guimond
10-14-2013, 06:13 PM
Donziweasel is getting a nice bit of info in this thread. I wonder is he is going to put an MX6.2 and B3 combo together for his 18 and call it a day for round one. I guess you could call that combo a very well balanced day.

Morgan's Cloud
10-14-2013, 06:55 PM
Donziweasel is getting a nice bit of info in this thread. I wonder is he is going to put an MX6.2 and B3 combo together for his 18 and call it a day for round one. I guess you could call that combo a very well balanced day.

I'm still looking forward to his input after possibly being misunderstood in my first post.

One good thing is that if what you bring up is a possibility and he's not happy , all it takes is a few extra $'s and you can just bolt on a B1

Greg Guimond
10-14-2013, 08:12 PM
Agree Morgan's Cloud. Others would know far better than I would, but the 320hp stock MX6.2 and a B3 could probably be "Lightly Whippled" and still run the B3 with excellent results. I have seen many 22-23 footers running B3 drives with newer 496 and older 454 Magnum power. Maybe Buizilla also puts a 250hp HT powerhead on his Yamaha dual prop wacker and see how that tracks. I am excellent at spending other peeps money :yes:

yeller
10-15-2013, 01:32 AM
Counter rotating props solved ALL my high speed handling issues. Granted, I'm using a BH, but the twin props took a boat that was down right frightening at high speeds and made it a pleasure to drive. Porpoising increased, but that's due to the shorter drive, not the dp's.

Morgan's Cloud
10-15-2013, 07:52 AM
Greg , if it was me , and I was operating at sea level , then knowing what I do , I'd go for the Volvo DP package.
DW , however , has that altitude issue going on and if he ever needs , or wants, to go with upgrading to overcome that problem then the availability of such accessories makes the choice for a Merc just about a shoe in. I don't think that there are easily accessible hot up parts for Volvos . Certainly someone with a little imagination could get it done though if they really wanted to .It would just be that much more difficult.

Yeller , was your boat originally a B1 ?

Pat McPherson
10-15-2013, 11:17 AM
Counter rotating props solved ALL my high speed handling issues. Granted, I'm using a BH, but the twin props took a boat that was down right frightening at high speeds and made it a pleasure to drive. Porpoising increased, but that's due to the shorter drive, not the dp's.

My boat was a little squirally with a couple of the props I tried above 60mph. She is now rock solid all the way to WOT and full trim @ 72mph GPS with a Merc Rev 4 prop.

I spoke with a fellow that rebuilt a mid 80s 18' Classic with a 400HP 383stroker and B3. He loved the boat and claimed it would run 70mph.
I also have a freind with a late 80s Donzi knockoff 18' with a 320HP Volvo DP. That boat handles great but will only top our at about 55mph. He runs alum props though.
I do recall seeing a couple of late 90s vintage 20' Cigs with 502Mag B3 power. I don't know any details but I would imagine Cig wouldn't have rig'd them that way if they didn't run great.
Anyone know of a 22' Classic running a Merc B3?

Donziweasel
10-15-2013, 07:41 PM
Sorry guys, got a little swamped. Anyway, I have dual B3's on my Formula. Love them. That boat is heavy as hell, and I can not only pop on a plane, but easily pull up a skier. This is at 7000 ft. When the drive is trimmed down, it turns on rails, damn near Donziesk. I am just throwing some ideas around. I think you are right in saying there could be more benefits to the performance run about market than possibly previously thought.

They do make an XR model, so this tells me Merc is expecting some big hp behind it. This may be geared toward the cruiser market, lets say a 28 ZX type deal, but doesn't mean it wouldn't make a heck of a drive on a 22 with a 500 or even a 525. Carl, want to try it? :) 18 is probably too small due to the weight, the damn things weight a ton! How do I know? I pulled both off the Formula to check the drive alignment this summer. My back still hurts, and I had two buddies (although one was kinda scrawny).

I have seen a few 22's with B3's for sale over the years. The owners seemed real keen on them.

Thanks for the feedback, it does make an interesting concept. If it matched the gimbal of a Bravo 1, and I am pretty sure it does, then it would be cool to hang on on the back of my 18 for a day to see what it would do. I guess if I was really curious, I could pull one off the Formula and try it when I switch the 18 from an Alpha to a Bravo. I still have the sea level props that came with it. I went from a 26P to a 22P when I bought it, stock Merc B3's props. Coupled to a whipple 18, might be cool, might be a disaster..... :)

yeller
10-15-2013, 08:18 PM
Yeller , was your boat originally a B1 ? Yes it was. I tried numerous props, but nothing could settle it down at high speeds (I'm talking 70+). Best prop was a 3 blade - Tempest. Also tried an Imco shortie. The shortie was in between the B1 and BH for handling. More porpoising than the B1, but not as much as the BH. It did improve the high speed handling, but nothing close to the BH. I give 98% of the credit for the handling improvement to the dual props. I never hit top speed (for more than a second or 2) with the B1...and usually couldn't go much past 70 without backing down. First time out with the BH, I could pin the throttle and hold it there, running mid 80's.


...Coupled to a whipple 18, might be cool, might be a disaster..... :)
I say..DO IT! Of course, that's because I'm spending your money, and not mine. :biggrin.:

Conquistador_del_mar
10-15-2013, 08:20 PM
Does anyone know if the Bravo III XR comes with a low water pickup or only the side pickups?

Greg Guimond
10-15-2013, 08:22 PM
DW, if it matches up and seeing you have a B3 that could be used as a week long donor, I would definitely throw it on your 18 and put a couple hundred miles on the 18 Classic with the stock 350 Magnum. Nothing to loose but a sore back :wink: I think with an 18 (could be wrong) it would take about 10-11hp for each 1mph gained in top speed.

Pat, good question on the 22 Classic running a B3. Someone will know. I can say that the Warlock 23XRI model which is 23' and 8'1" beam and also has a 24 degree bottom runs 70-71 with a 502 Magnum (415) and a B3. The same boat with a 454 Magnum (385) and a B3 runs 67-68. The same boat again with a MX6.2 and a B1 runs 60 on the money on GPS.

ITTLFLI
10-16-2013, 08:14 AM
First time out with the BH, I could pin the throttle and hold it there, running mid 80's.


My experience exactly!! I didnt have any ill handling with the B1 but when i went to the BH the counter rotating props absolutely makes the boat handle incredible!!!

Pat McPherson
10-16-2013, 09:09 AM
My experience exactly!! I didnt have any ill handling with the B1 but when i went to the BH the counter rotating props absolutely makes the boat handle incredible!!!

Guys, Are you running the BH on the standard 22C hull? I thought the 22C hulls with BH drives had mods for more bow lift / some sort of rocker added???

Donziweasel
10-16-2013, 10:19 AM
Funny thing to me is that the Blackhawk has this fearsome reputation of being very unstable and hard to drive, but also fast. It seems Glen and Byron had the exact opposite results. Still fast, but very stable. It even cured Glen's boat, which I remember him saying a few years back was almost undrivable with the Bravo. I am getting a little more interested in trying the Bravo 3. Of course, the B3 is not a surface piercing drive, so it is hard to compare. The theme does seem to be that a dual prop, whether a DPX, B3 or Blackhawk have extremely stable driving characteristics. Maybe there truly is more to this. Any one know what Merc has said the max hp for the B3XR is? Notice I said Merc's specs, not reality.

I am not looking for top speed, been there done that. I am an older family man now. I could lose 3-4 mph on top for stability.

ITTLFLI
10-16-2013, 11:10 AM
Funny thing to me is that the Blackhawk has this fearsome reputation of being very unstable and hard to drive, but also fast. It seems Glen and Byron had the exact opposite results. Still fast, but very stable. It even cured Glen's boat, which I remember him saying a few years back was almost undrivable with the Bravo. I am getting a little more interested in trying the Bravo 3. Of course, the B3 is not a surface piercing drive, so it is hard to compare. The theme does seem to be that a dual prop, whether a DPX, B3 or Blackhawk have extremely stable driving characteristics. Maybe there truly is more to this. Any one know what Merc has said the max hp for the B3XR is? Notice I said Merc's specs, not reality.

I am not looking for top speed, been there done that. I am an older family man now. I could lose 3-4 mph on top for stability.

My BH is on a standard 1994 22 hull. Yes I was told it would not work. Been running it since 2008.

DW- I haven't driven a B3 but I can tell you I ran next to (or in front of ;) )that Cig 20 that had the 496ho and B3 for the better part of a day on the Detroit river run and it was Rock solid!

I would not hesitate to go the B3 route!! STABILITY...

Morgan's Cloud
10-16-2013, 12:43 PM
DW , do you know what gear ratio and prop size you have on your cruiser B3's ?

Although it'll be purely for 'test purposes' you can pull it off easily . Without the props on them a B3 is about 8 pounds heavier than a B1 . The second prop would take the total package weight up to the full package difference of 21 pounds or whatever it is.

I can give you a pretty close estimate that IF , and that's a big 'if' , you had the 2.0:1 ratio on your cruiser drives you'd need a 26'' prop set to utilize the power of a 350Mag in an 18C . As you already would know , the props are clearly marked what size they are.

I would really like to hear that you'll give it a shot and see your 'before' and 'after' impressions .

Carl C
10-16-2013, 12:49 PM
"They do make an XR model, so this tells me Merc is expecting some big hp behind it. This may be geared toward the cruiser market, lets say a 28 ZX type deal, but doesn't mean it wouldn't make a heck of a drive on a 22 with a 500 or even a 525. Carl, want to try it?"

Nopers! My boat is dialed in with a proven package and one prop :) . I did blow the XR upper this year but it was due to a nut backing off and it has been replaced.

Donziweasel
10-16-2013, 01:54 PM
MC, I am not sure Cruiser is the right word for the Formula. I would say more performance cruiser. It is a 27SS with twin throttle body injected 350's. She will run over 50 at sea level, about 48 at my altitude.

http://www.formulaboats.com/270-sun-sport

It actually looks like a big runabout than a cruiser. I can not tell you how well it handles with the Bravo3 and it is HEAVY!


I am pretty sure the front one is 14 1/4 diameter and the rear is 15 3/4. Both are 22 pitch, but I still have the 26 pitches that came with it. I am sure I would get close to the rev limiter, but before I got the RPM's that high, I could at least get a feel for it. Re-propping hurt the wallet, as I had to buy 4 props. It sucked. I will check the gear stamp when I get home.

Morgan's Cloud
10-16-2013, 04:11 PM
I only used the word 'cruiser' in the context that compared to an 18C that's what some people might more equate it to .
What you have in the Formula is similar to a new version of my Mag 25 , and that's a very heavy 25.5 footer by today's standards.

You might have the next ratio up from the 2:1 but there is a possibility that you have the 2:1 . If that's the case the 26'' prop set will put you close to factory spec on top RPM IF you were at sea level.

I believe that the whole concept that B3's are for heavy cruisers originated from the fact that Merc introduced the B1 first , probably as their one and only drive . Then they realized the success that Volvo was having with their Dp's and (with only a few engineering tricks) introduced the B3 as an alternative to the B1 but aimed at the heavier , larger boats. Then came the B2 which was REALLY for big and heavy boats .

No doubt about it , buying propsets for B3's can be a stinger though , that's why if you're doing it yourself you've got to get it right from the get go.

Actually I'm sort of surprised that you're only loosing 2mph or so at your altitude.
How high up are you again ? I can't quite recall . But with that scenery you want to take it all in instead of running 70+ everywhere.

Donziweasel
10-16-2013, 06:20 PM
MC,
I bet my Formula is every bit of 9000 pounds. It is a tank. Todd has the same boat and I think he was running 54-55, so I lost 7-8 mph. I never got to run mine at sea level, so I am not sure what it had as a base. I do know it ran 4600-4700 rpms down at Havasu, where is came from. Up here the most I could get it to turn was 4100. I know dropping a pitch is usually 150-200 rpms, but my experience was with Bravos and Alphas, not B3's. Merc Bravo 3 props are only even numbers, 20,22, 24, 26. There are some companies making other pitches, but since, like you said, it is expensive and you had better get it right the first time, I stayed with Merc. The 22's turn 4600-4700 now. My enignes aren't MAGS, so it is dialed in perfectly. I was ready to drop a gear if I couldn't get the rpm's in the desired range. So, from my experience, going down four pitches increased rpms 500-600. So it seems the B3 reacts similar to B1 and Alphas on pitches. Luckily I got it right.

I can run WOT in any conditions, slop, chop, glass, and use one finger, even the pinky, on the wheel. Although my hull is not stepped, I bet if you could get it to 70 or even more, you could tap dance on the deck it is so smooth. While running straight is fine, real boating is turning. I can drop those drives and make it turn like a 16. I even blew my friends away one day when I was running fast and went into a small cove. I dropped the drives and spun it around like a 16. Amazing. I will say that some of this is due to the Formula hull design, but the B3's are probably the main reason. Another thing is I can't get them to blow out in a turn either.

The reason I got interested in them on a smaller classic is because of the Formula. With handling that nice, I started to wonder.......

Jim, my buddy with the 245 Rinker deck boat has a B3. That boat is a heavy pig, but handles amazing. I was really amazed, due to the much flatter hull, how well it handled the chop and slop. His was running 26's at sea level too and we dropped to 22's. I am just amazed with that hull how well it handles rough stuff.

The only problem now is, the boat is in storage 100 miles away for the winter. I bet it has the same gears as Todd's did. I will ask him what his had........maybe he remembers, he moved up to a 38 a few years ago.

Greg Guimond
10-16-2013, 06:38 PM
I see you doing the B3 donor on the 18 for a week, especially if it is only 25lbs heavier overall. Should be a pleasant surprise for sure.

yeller
10-16-2013, 08:35 PM
Funny thing to me is that the Blackhawk has this fearsome reputation of being very unstable and hard to drive, but also fast....... DW, I believe the reputation of being hard to drive is the "true" blackhawk boats. Those have extra rocker in the hull which makes them faster, but harder to drive. On a "normal" 22, the BH just makes it faster, and easier to drive.
Although.....if I remember correctly, MOP tried a BH on his 22 and said it wouldn't handle.

I would love to try a B3 XR, but I think the props I would need would push the cost too high. I've found that the shorter the drive, the more the porpoising increases. I have to go upper 50's for it to stop (with the BH). I would gladly give up a few mph to keep the handling of the BH and reduce the porpoising.

Greg Guimond
10-16-2013, 10:43 PM
Looks like this one lived with a 525 Blue ........


2009 Bravo III XR Drive complete lower unit for sale....81 hours on drive...has 4X3 - 25 pitch labbed props... 1:65 gear ratio...drive has been serviced regularly and was matched with a 525 merc with standard hp......asking $ 2700

MDonziM
10-16-2013, 11:16 PM
DW, I believe the reputation of being hard to drive is the "true" blackhawk boats. Those have extra rocker in the hull which makes them faster, but harder to drive. On a "normal" 22, the BH just makes it faster, and easier to drive.
Although.....if I remember correctly, MOP tried a BH on his 22 and said it wouldn't handle.

I would love to try a B3 XR, but I think the props I would need would push the cost too high. I've found that the shorter the drive, the more the porpoising increases. I have to go upper 50's for it to stop (with the BH). I would gladly give up a few mph to keep the handling of the BH and reduce the porpoising.

Yeller,
When I changed my regular 94' stock 502/bravo1 to a bh drive I saw only 1 mph increase in top speed. (71-72) With the 540 motor the real benefit is stability at high speeds. Another consideration for the bh hull reputation besides the rocker is that we are running these drives 2-3" deeper in the water, making them more predictable. My boat will go 84-85 but I bet if you could raise the X 2-3" it would be 5-7 mph faster I bet.
- Marshall

Pat McPherson
10-17-2013, 08:50 AM
Learning lots about my 22C...
Sounds like with my stock 502 power she good as is now that I've found the right prop. If I ever want to up the power, a drive change from the standard B1 may be appropriate...
My only short term addition to better performance will be external steering…
Thank you to all that have posted their experiences…

MOP
10-17-2013, 11:15 AM
As mentioned above I ran a BH on my 22 with a mild 383, it did not have the gonads of a big block. The boat handled great and at any RPM up to 4000 had way less slip than the BravoX which replaced it, above 4000 it made to much stern lift making the making the hull run flat. Speed with the BH topped at 59, the BravoX topped out at 65.5. I have said this a bunch of times, to get the best out of a BH it must be run a 17-1/2 X. If mounted any lower it produces way more stern lift than when mounted properly, most all points of the BH are covered in the posts below my point if you are going to do it do it right!

http://www.donzi.net/forums/showthread.php?61567-Blackhawk-16-goes&highlight=blackhawk

http://www.donzi.net/forums/showthread.php?68218-How-much-HP-to-a-blackhawk&highlight=blackhawk

Donziweasel
10-17-2013, 06:17 PM
Phil, you got me thinking. What would be really cool on a B3XR? A -2 shorty.

Since no one has done it on an 18, I think I will pull one of the B3's and put it on the 18 with the 26 pitch props. Considering about every possible configuration of drive and engine has been tried on a Classic, this is one of the last. We have Ilmore 22's, Arneson 18's and 22's, turbos, blowers, a BH on a 16, DPX and B3 22's, shorties, #6's, Konrads, strokers, different x's, shorties, and about everything else. Well, someone should try it just to see what happens...... :) I guess I will be the guinea pig. Why not? It should only take an hour or so to switch the drives with a couple of buddies.

MOP
10-17-2013, 06:53 PM
IMO you will give up a tad of speed for great handling, but you won't have to raise the X as is the case with BH. Like Jim mentioned running higher pitch on the back wheel works well front feeds the back, when I switched to 24X26 straight line improved as did RPM "vs" speed IE less slippage.

Greg Guimond
10-17-2013, 07:09 PM
Since no one has done it on an 18, I think I will pull one of the B3's and put it on the 18 with the 26 pitch props.

I knew you would try out the donor B3 ;)

Pat McPherson
10-18-2013, 08:57 AM
http://www.donzi.net/forums/showthread.php?61567-Blackhawk-16-goes&highlight=blackhawk

http://www.donzi.net/forums/showthread.php?68218-How-much-HP-to-a-blackhawk&highlight=blackhawk

I read these threads front to back. The only Donzi I've seen that would be crazier would be GEO in his 18. After a drive by at the CT river run, he showed me 109 on his GPS.
Not me, no way, the fastest I've driven was 78+ in my 24' Super...

Greg Guimond
10-18-2013, 10:02 AM
I thought that I had read somewhere that the Bravo 3 drive had some somewhat significant enhancements for the 2011 model year. Does anyone else know anything about that?

roadtrip se
10-18-2013, 11:13 AM
I thought that I had read somewhere that the Bravo 3 drive had some somewhat significant enhancements for the 2011 model year. Does anyone else know anything about that?

That was the XR. Drive and props.

Go for it Weasel!

Greg Guimond
10-18-2013, 12:18 PM
Thanks road, I wasn't sure if it was the year the XR was intro'd

Pat McPherson
10-18-2013, 02:31 PM
I know a fellow with a big, I think 36-37', Formula PC with 525EFI B3XRs. He claims it will go over 60mph, but I've not seen him away from the dock...

Donziweasel
10-18-2013, 06:25 PM
I think a Bravo is rated for 400hp, Bravo x, 500 and the XR 600. Would the B3 have the same ratings?

Greg Guimond
10-18-2013, 07:32 PM
They run the standard Bravo 3's all the time out West with 415hp at 70mph.

Ghost
10-18-2013, 09:03 PM
My understanding is the Bravo X is rated for 450 by Merc.

Greg Guimond
10-23-2013, 07:15 PM
I just saw another guy running a B3 behind a stock 502 Magnum with no problems :smile:

Ghost
10-23-2013, 10:26 PM
Another data point: looks like Merc now rates the Alpha up to 300 and prescribes the Bravo X and XR (but not the base Bravo) for its 380hp 8.2 and above. Which I think puts the 320 hp 6.2l as the only motor Merc won't sell with an Alpha but will sell with a base Bravo.

All of which is about what Merc wants to warrant, but, FWIW.