A little boat and a simple diesel project

Discussion in 'Propulsion' started by PickleRick, Dec 4, 2017.

  1. PickleRick
    Joined: Dec 2017
    Posts: 20
    Likes: 0, Points: 1
    Location: Greenville

    PickleRick Junior Member

    A few questions regarding a diesel conversion. 78 carver santa cruz 2567. 21 ft loa. 8 ft wide. Modified v hull approx 5500 lbs

    Im using a 2.0 tdi vw diesel. Approx 170 hp and 300 ft lbs torque.

    Stock turbo manifold, slightly larger than stock turbo. Water injected downpipe.

    Im going to ceramic coat the outside of the manifold and downpipe. Pack it in ceramic wool then heat tape. Dei turbo jacket for turbo and wrapped down pipe. Plan on adding 1 or 2 12 inch cooling fans to both sides of the engine hatch bringing in fresh air. Will have two 320 cfm bilge blowers to suck out hot air. Exhaust will exit stock exhaust port for alpha one. Does this sound sufficient enough? I'll also dynomat the entire inside of the hatch, sides and bottom of hatch cover. Is there a target temp inside the hatch i should aim for?

    Gearing and prop. I know the alpha isn't going to hanle all that diesel power for long. A bravo will be added later once bugs are worked out. My motor puts out peak torque from 1900 to 2500 rpms and peak hp about 4000. That is a stock dyno. Ill have a better flowing turbo, exhaust and more efficient tune so ill have a slightly broader torque range but the top hp rpm and prefered redline are around the same.

    What gear ratio would you recommend? I currently have the 1.5 v8 alpha.

    If the specs of a 1980 and 1978 carver santacruz are the same or similar the boat will plane around 16 mph requiring 60 hp to do so. The max i care to run is 25. If she will sit with a comfortable nose ill be happy cruising at 20. (Ill have oversized trim tabs)

    Last but not least, if we can get the ideal gearing next is what prop?

    Once i work out what gearing and get bugs worked out ill look for a permanent bravo.

    Thank you guys

    Attached Files:

    Last edited: Dec 7, 2017
  2. PickleRick
    Joined: Dec 2017
    Posts: 20
    Likes: 0, Points: 1
    Location: Greenville

    PickleRick Junior Member

    I simplified the thread to maybe get a few opinions
  3. Carolina Fishing
    Joined: Dec 2017
    Posts: 3
    Likes: 0, Points: 1
    Location: USA

    Carolina Fishing New Member

    Not worth changing the gear ratio of your Alpha. Go directly to a bravo.
  4. PickleRick
    Joined: Dec 2017
    Posts: 20
    Likes: 0, Points: 1
    Location: Greenville

    PickleRick Junior Member

    Agreed 100% however for trial and error purposes the alpha makes better sense. Youll spend weeks looking for a spare used bravo vs the 20 on Craigslist for a dime a dozen. Having several already laying around the house also helps. Do alpha and bravo props even interchange?

    Once the kinks are worked out a bravo will be installed.
  5. 7228sedan
    Joined: Nov 2009
    Posts: 347
    Likes: 15, Points: 18, Legacy Rep: 60
    Location: New Jersey USA

    7228sedan Senior Member

    Bravo & Alpha drives are not at all interchangeable. Different props as well as gimbal assemblies/transom housing. You'll need to cut a new hole in the transom to mount a Bravo.

  6. gonzo
    Joined: Aug 2002
    Posts: 16,839
    Likes: 1,736, Points: 123, Legacy Rep: 2031
    Location: Milwaukee, WI

    gonzo Senior Member

    A 350, which that gear ration matches has 260 HP and 300 ft lb of torque. That diesel will not overpower the sterndrive.
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