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More than 65 MPH with a Bravo III?

Old 08-10-2015, 11:49 PM
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Got it...
Now can anyone tell me what is the difference between the lower units? Do I want a swept back or a non-swept back unit? Is it faster? Do I care?
What is an oiler? Do I have one currently (B3) do I need to get a B1 that has it?
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Old 08-11-2015, 12:05 AM
  #22  
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Just saying and not to sound bad here. You have a 23 Chaparral family rec boat that is designed & rated only for a certain speed to not exceed most likely over 70 mph if not maybe 75 mph would be the complete 100 % max and most likely very uncontrollable at that those speeds on top of.

what is your steering set up cable and is it rack or rotary cable steering ? - and no external steering either is this correct ? Do you have trim tabs - if so what brand and size ? What shape and condition is your gimbal ring in ? any slop there - side to side and up & down ? how about your motor mounts most likely lagged bolted is this correct ? how about the transom ? How old is your boat ?

All these forms of family rec boat manufacturers list max horsepower ratings and really do not want them exceeded - That Chaparral hull was never designed to be a speed demon anyways. Everyone I have every driven was very slow no matter of the power from 18 footers to up to 30 ft Chaparrals . just saying, not knocking your boat. IMO I would leave it alone.

Last edited by BUP; 08-11-2015 at 12:08 AM.
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Old 08-11-2015, 04:17 AM
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S i g h ; ; Again.... 502 EFI warmed to 500 HP, Billet tabs (12"x17") outboard steering, the motor mounts are bolted through the stringer, the interior was upgraded with stand up bolsters, the rear has deep seats and oh-sh$t bars (Billet off shore controls to be installed very soon).

I am trying to replicate a "know boat" identical to mine that is doing 71MPH (GPS) with 4 souls on board and loaded for the day in less than perfect water. He has 480 HP and B1 with a 24P prop that has been worked and has a far amount of a cup to it (454 carb motor that is all stock except for a pro charger). I had a Baja 232 with a 496 and XR1 drive,that was doing 70MPH, this guys Chaparral was faster, had more room was MUCH more comfortable and important to a boater on the mighty Colombia river unlike the Baja the deck was safe to walk out on for anchoring in rough water. I sold the Baja and started looking for this Chaparral.

I know that my boat is not the most performance minded boat in the world, However, it is a hand made high quality boat and "this" model was designed to be a high performance boat (it came from the factory with 502) and I am not looking to change the universe, making a 4800 pound boat go 70MPH on 500 HP does not require voodoo

I have the information I need about gear ratios, now I need guidance on which lower unit... What is a swept back (and why would I want it)? I currently have an "oiler" upper, what do I need to know about getting a lower that is computable with it?
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Old 08-11-2015, 06:59 AM
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I did a full swap.

Put a ad on c.l. for sale / trade a b1 for a b3. Lots of cruisers and fishing boats with a b1 want a b3
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Old 08-11-2015, 08:11 AM
  #25  
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Originally Posted by BUP
Just saying and not to sound bad here. You have a 23 Chaparral family rec boat that is designed & rated only for a certain speed to not exceed most likely over 70 mph if not maybe 75 mph would be the complete 100 % max and most likely very uncontrollable at that those speeds on top of.

what is your steering set up cable and is it rack or rotary cable steering ? - and no external steering either is this correct ? Do you have trim tabs - if so what brand and size ? What shape and condition is your gimbal ring in ? any slop there - side to side and up & down ? how about your motor mounts most likely lagged bolted is this correct ? how about the transom ? How old is your boat ?

All these forms of family rec boat manufacturers list max horsepower ratings and really do not want them exceeded - That Chaparral hull was never designed to be a speed demon anyways. Everyone I have every driven was very slow no matter of the power from 18 footers to up to 30 ft Chaparrals . just saying, not knocking your boat. IMO I would leave it alone.
His hull is similar to mine. Just a couple feet shorter. Rounded lifting strakes that the inner ones end mid-ship and the outer ones run to the stern on the "extended v-plane" portion of the hull (hull extends past drive on the sides). Rounded keel at the transom. Drive deep in the water. Hull does not like stern lift at higher speeds as I can attest to by going from a 3 x 3 prop set to a 4 x 3 XR prop set. As stated, not a speed hull by any stretch of the imagination.

I believe his biggest gain going to a Bravo I would be from a raised drive height. Would be interesting to see the difference between a standard Bravo I lower vs. a shorty with properly dialed-in props.

Hull at transom.
Attached Thumbnails More than 65 MPH with a Bravo III?-chappy-hull.jpg  
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Old 08-11-2015, 08:15 AM
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Originally Posted by BUP
bravo III are propshaft leakers all the time. More times than not I see these leak gear oil leak thru the propshaft seal while running the down the lake. the air pocket behind the prop(s) creates a vacuum that helps pull gear oil out the seal while running in forward gear down the water ways.

here is a SB about some Bravo info and gear ratios along with current and older gear teeth counts. IMO it is a very good info piece/ - FWIW to others

I will try to find and post the bravo III propshaft seal change SB to help with the gear oil leaks but it help a tad as they still leaked even with the newer seal replacement.

http://www.marinemechanic.com/merc/d...eplacement.PDF
.
Good info BUP. Although I have to disagree about the elaking, at least based on my experience. I've had my B3 for 5 years now, and it's never used gear oil, nor shown water in the oil - and I put 50+ hours a season on it. The tube to the reseviour is clean and open so if it was leaking, I would see it as use or water. So, I'm pretty sure it's not leaking - maybe I got the lucky one
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Old 08-11-2015, 09:52 AM
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Originally Posted by apollard
Good info BUP. Although I have to disagree about the elaking, at least based on my experience. I've had my B3 for 5 years now, and it's never used gear oil, nor shown water in the oil - and I put 50+ hours a season on it. The tube to the reseviour is clean and open so if it was leaking, I would see it as use or water. So, I'm pretty sure it's not leaking - maybe I got the lucky one
10 seasons and 400 hours and not a leak from mine either other than last year I had to replace the gear lube reservoir as it leaked where the wires pass thru the bottom.
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Old 08-11-2015, 10:30 AM
  #28  
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Please keep in mind that it can still look like your B III does not leak by looking at the gear oil level in the clear reservoir - the problem is the reservoir can stay full and still leak from the drive a little bit at a time. The reservoir gets very clogged at the bottom forming thick gelled gear oil overtime that will stay full all the time. They need to be cleaned out once a year bare min. Depending on what gear oil you use it can be worse or not taking place at all for the gear lube reservoir bottom gelling up. Just saying
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Old 08-11-2015, 11:08 AM
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I change the drive oil every year. Never had any indication that it leaked

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Old 08-11-2015, 11:29 AM
  #30  
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Originally Posted by BUP
Please keep in mind that it can still look like your B III does not leak by looking at the gear oil level in the clear reservoir - the problem is the reservoir can stay full and still leak from the drive a little bit at a time. The reservoir gets very clogged at the bottom forming thick gelled gear oil overtime that will stay full all the time. They need to be cleaned out once a year bare min. Depending on what gear oil you use it can be worse or not taking place at all for the gear lube reservoir bottom gelling up. Just saying
I was lucky and found this by accident. The bottles always looked full but for some reason I checked them and found the bottom inch was thick sludge. Cleaned them out real good and installed to find they worked properly (did not fill the drive all the way up so I could see if the bottle did it's job). Had my drive lost fluid I never would have known otherwise.
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