Need Advice - Upgrading from Merc Alpha G1 to Bravo, XR, SSM, IMCO, etc
05-06-2022 | 12:33 PM
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Need Advice - Upgrading from Merc Alpha G1 to Bravo, XR, SSM, IMCO, etc
I need some advice as I'm conflicted. I purchased a project boat last year that I have serviced, fixed, and used all last summer. It does GPS verified 49.9mph (sigh) and I only take it in Freshwater lakes here in Alabama. Yes I know I should buy a 25' Baja with a 496cu Fuel Injected setup that comes with a Bravo 1 drive - and modify from there - but I'm interested in learning more through doing - rather than buying. I like the idea of a sleeper boat - something that shouldn't go 60+ mph but does. I say this so you can understand my mindset a little more.
Boat - 1987 Cobalt 19BR
Engine - 305 SBC - carb'd
Drive - 1.5:1 Mercury Alpha Gen 1
Props - 4 blade SS Mercury 19 & 21 pitch
Uses - Towing the kids around the lake & Racing other boats
The owner - Engineer for professional LMP3 race team, Engine calibrator for high performance cars, I love big turbos, E85, and making jam. I have access to CNC mills, lathes, composites fabrication, metal fabrication/welding, motorsport wiring, ECU programming, engine dyno, machine shops, etc. Basically I work on race cars - just starting to play with boats.
Max Load (weight) - 750 pounds.
This year's upgrade
Chevy LT1 Gen V Small Block L83 - All Aluminum 5.3L V8 Direct Injected with variable cam timing
- Callies H-Beam Forged Rods 6.125" C-C
- Diamond Forged Pistons 11.7:1 CR (short comp height)
- New Forged GM Crankshaft from L86
- APR Mains, Rod, and headstuds.
- BTR Camshaft (210/223 .540"/.540" 111+6 +11% FUEL LOBE)
- L86 Intake manifold and Throttle Body
- Raychem'd and potted factory wiring harness with stock ECU (programmed with WinOLS & HPTuners)
- Volvo Penta v8-300 Watercooled exhaust manifolds, segregated cooling system with heat exchangers (basically used their marinization of the L83 to simplify the install)
- glassed in motor-plate setup with adjustable solid engine mounts. (taking strain off transom)
- Surge tank setup, Bosch Brushless Fuel pump, Injector Dynamics Fuel Filter, AN lines (all Ethanol compatible to run E85)
Phase 1 of the engine will be NA making approximately 400HP (up from probably 175hp with the 305)
Phase 2 will be FI - likely a liquid to air turbocharged setup - But for now - I want to get the boat in the water this year - and scope creep always makes that not happen.
This brings me to my question. I need help picking an outdrive that will be robust. I need to upgrade my outdrive to take the torque I want to put through it. The Gen 1 Alpha drive *may* survive the L83 if it was never launched (IIRC boaters call this a holeshot) or jumped (exit and re-enter the water) - aka dynamic shock/ high speed wheel hop. I will not be jumping the boat - but I would like to holeshot it whenever I want.
Based on my "internet research" and reading this forum as well as others. It would appear I need to upgrade to a Bravo drive. So I'll need to drill the transom for 2 extra holes to mount the new transom assembly/ Gimbal housing, add a sea-water pump to the engine (Volvo Penta Drive Gen V engines have these already - so that's easy), and hang my new outdrive.
My "internet research" has also taught me that there are many flavors of the Bravo drive. Old generation, 0M Generation/ swept back cap, and the current generation MY2022 Bravos. Through the generations there were upper housing upgrades, gear upgrades, introduction of the X and XY and XR drives (net forged gear sets, etc) I've read lots of discussions and threads regarding how much power each setup can take. I've also learned that used bravo gimbal assemblies are most likely all garbage because of the steel bearing mount that wears out at the top of the gimbal. So buying a used gimbal assembly is highly suspect. I also fear that in most cases - if I'm buying a used Bravo drive - it will likely have damage that I will discover months later - and end up being way more money invested than I should be for a base level Bravo drive.
These are my current ideas for picking an outdrive
1) Used Bravo 1 drive (uppper & lower) with transom assembly and gimbal housing. Buy from a marina who can assure me that it came from a working/running boat - that doesn't seem shady. Expect to have to do some service work/ take apart and replace worn items, weld/refinish/paint. $3500 - $4000k all in. Install and pray I don't blow it up.
2) Used Bravo 1 drive (uppper & lower) with NEW transom assembly and gimbal housing. Buy from a marina who can assure me that it came from a working/running boat - that doesn't seem shady. Expect to have to do some service work/ take apart and replace worn items, weld/refinish/paint. $6500 - $7000k all in. Install and pray I don't blow it up.
3) Buy a used Bravo XR drive (upper & lower) with used transom assembly and gimbal housing. This will likely be bough from another enthusiast who has repowered his boat and like to jump holeshot - all the **** I wanna do. Likely hood of damage - much higher. Expect to have to do some service work/ take apart and replace worn items, weld/refinish/paint. 10,000-12,000
4) Buy a used Bravo XR drive (upper & lower) with NEW transom assembly and gimbal housing. This will likely be bough from another enthusiast who has repowered his boat and like to jump holeshot - all the **** I wanna do. Likely hood of damage - much higher. Expect to have to do some service work/ take apart and replace worn items, weld/refinish/paint. 13,500-15,500
5) Buy a new Bravo XR drive (2022 model) wtih New transom assembly. DWP 5-5E31200UP Try to get a deal on it... so far retail prices are in the 14,xxx range with a transom assembly ~3500? Total 18,000+
I've seen IMCO upgrades, Bravo Shop B-MAX, aTRS drives, SSM2, SSM3, M6, M8, Arneson drives, Velvet drives, etc. Not sure if I should be looking at any of these options seriously - some of them are way out of my budget. Another point regarding budget - i plan on keeping the complete 305 SBC/Alpha drive for the boat - so when I decide to buy a Baja - I can take my LT/Bravo setup with me for the new boat. I'm also not terribly concerned about spending too much money on an old ****ty boat - as its drivetrain parts that can be swapped out - I'm not blowing 8k on a paint job.
well - thank you for reading my ADHD fueled post. I look forward to your ideas, criticisms, and advice. Thank you all.
Boat - 1987 Cobalt 19BR
Engine - 305 SBC - carb'd
Drive - 1.5:1 Mercury Alpha Gen 1
Props - 4 blade SS Mercury 19 & 21 pitch
Uses - Towing the kids around the lake & Racing other boats
The owner - Engineer for professional LMP3 race team, Engine calibrator for high performance cars, I love big turbos, E85, and making jam. I have access to CNC mills, lathes, composites fabrication, metal fabrication/welding, motorsport wiring, ECU programming, engine dyno, machine shops, etc. Basically I work on race cars - just starting to play with boats.
Max Load (weight) - 750 pounds.
This year's upgrade
Chevy LT1 Gen V Small Block L83 - All Aluminum 5.3L V8 Direct Injected with variable cam timing
- Callies H-Beam Forged Rods 6.125" C-C
- Diamond Forged Pistons 11.7:1 CR (short comp height)
- New Forged GM Crankshaft from L86
- APR Mains, Rod, and headstuds.
- BTR Camshaft (210/223 .540"/.540" 111+6 +11% FUEL LOBE)
- L86 Intake manifold and Throttle Body
- Raychem'd and potted factory wiring harness with stock ECU (programmed with WinOLS & HPTuners)
- Volvo Penta v8-300 Watercooled exhaust manifolds, segregated cooling system with heat exchangers (basically used their marinization of the L83 to simplify the install)
- glassed in motor-plate setup with adjustable solid engine mounts. (taking strain off transom)
- Surge tank setup, Bosch Brushless Fuel pump, Injector Dynamics Fuel Filter, AN lines (all Ethanol compatible to run E85)
Phase 1 of the engine will be NA making approximately 400HP (up from probably 175hp with the 305)
Phase 2 will be FI - likely a liquid to air turbocharged setup - But for now - I want to get the boat in the water this year - and scope creep always makes that not happen.
This brings me to my question. I need help picking an outdrive that will be robust. I need to upgrade my outdrive to take the torque I want to put through it. The Gen 1 Alpha drive *may* survive the L83 if it was never launched (IIRC boaters call this a holeshot) or jumped (exit and re-enter the water) - aka dynamic shock/ high speed wheel hop. I will not be jumping the boat - but I would like to holeshot it whenever I want.
Based on my "internet research" and reading this forum as well as others. It would appear I need to upgrade to a Bravo drive. So I'll need to drill the transom for 2 extra holes to mount the new transom assembly/ Gimbal housing, add a sea-water pump to the engine (Volvo Penta Drive Gen V engines have these already - so that's easy), and hang my new outdrive.
My "internet research" has also taught me that there are many flavors of the Bravo drive. Old generation, 0M Generation/ swept back cap, and the current generation MY2022 Bravos. Through the generations there were upper housing upgrades, gear upgrades, introduction of the X and XY and XR drives (net forged gear sets, etc) I've read lots of discussions and threads regarding how much power each setup can take. I've also learned that used bravo gimbal assemblies are most likely all garbage because of the steel bearing mount that wears out at the top of the gimbal. So buying a used gimbal assembly is highly suspect. I also fear that in most cases - if I'm buying a used Bravo drive - it will likely have damage that I will discover months later - and end up being way more money invested than I should be for a base level Bravo drive.
These are my current ideas for picking an outdrive
1) Used Bravo 1 drive (uppper & lower) with transom assembly and gimbal housing. Buy from a marina who can assure me that it came from a working/running boat - that doesn't seem shady. Expect to have to do some service work/ take apart and replace worn items, weld/refinish/paint. $3500 - $4000k all in. Install and pray I don't blow it up.
2) Used Bravo 1 drive (uppper & lower) with NEW transom assembly and gimbal housing. Buy from a marina who can assure me that it came from a working/running boat - that doesn't seem shady. Expect to have to do some service work/ take apart and replace worn items, weld/refinish/paint. $6500 - $7000k all in. Install and pray I don't blow it up.
3) Buy a used Bravo XR drive (upper & lower) with used transom assembly and gimbal housing. This will likely be bough from another enthusiast who has repowered his boat and like to jump holeshot - all the **** I wanna do. Likely hood of damage - much higher. Expect to have to do some service work/ take apart and replace worn items, weld/refinish/paint. 10,000-12,000
4) Buy a used Bravo XR drive (upper & lower) with NEW transom assembly and gimbal housing. This will likely be bough from another enthusiast who has repowered his boat and like to jump holeshot - all the **** I wanna do. Likely hood of damage - much higher. Expect to have to do some service work/ take apart and replace worn items, weld/refinish/paint. 13,500-15,500
5) Buy a new Bravo XR drive (2022 model) wtih New transom assembly. DWP 5-5E31200UP Try to get a deal on it... so far retail prices are in the 14,xxx range with a transom assembly ~3500? Total 18,000+
I've seen IMCO upgrades, Bravo Shop B-MAX, aTRS drives, SSM2, SSM3, M6, M8, Arneson drives, Velvet drives, etc. Not sure if I should be looking at any of these options seriously - some of them are way out of my budget. Another point regarding budget - i plan on keeping the complete 305 SBC/Alpha drive for the boat - so when I decide to buy a Baja - I can take my LT/Bravo setup with me for the new boat. I'm also not terribly concerned about spending too much money on an old ****ty boat - as its drivetrain parts that can be swapped out - I'm not blowing 8k on a paint job.
well - thank you for reading my ADHD fueled post. I look forward to your ideas, criticisms, and advice. Thank you all.
