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  1. #1
    Jeepster's Avatar
    Join Date
    Jul 2007
    Quebec, Canada

    V6 or V8 Jet-Boat...?

    Crazy idea...

    Anybody out there ever thought about putting a V6 or V8 engine in a Sea-Doo Jetboat...???

    That would surely put a smile on a face...!!!

  2. #2
    King_Of_Fun's Avatar
    Join Date
    Jul 2007
    Catawba Island, Ohio
    Aside from the extreme difference in weight, engine rpms would be the next limiting factor. You would either need a real jet boat pump (with a much larger impeller) or get the engine to turn close to 8000 rpms with the existing pump... Ron

  3. #3
    mark2m's Avatar
    Join Date
    Mar 2008
    Greenwood Lake, NY
    Nope can't say I have but I thought it would be cool to throw a v-twin in there. Small light weight motor, good torque and HP, will rev to 10,000rpm, 4 stroke. Probable sound pretty cool also.


  4. #4

    Join Date
    Sep 2007
    Lexington, Ky
    yeah, that's the biggest obstacle in putting an automotive engine, or a big V8 in one of these jet boats.

    First problem as stated is getting the RPM's within the ideal 8-9k range that these pumps are optimized for. Your next biggest issue is going to be to find a motor with a low enough driveshaft output to align to the pump properly. Thats why most all pwc marine engines are dry sump (amoung other reasons) as the oil pan usually raises the engine up, and puts the engine up to high.

    However, if you were so inclinded to build a step up gearbox, this would solve both issues. I wish I had taken on a large single motor project like this instead of my twin engine boat build.

    My engine choices are:

    S2000 F22C motor (2.2, loves a turbocharger, and no gearbox required. It also has a decently low output shaft location, would require oil pan modification though)
    small block Chevy? (not my first choice, but most logical, id want an all aluminum one for sure)
    Inline-6 Supra turbo motor (Has the RPM's has the power, length could be a problem, unsure of oiling system mods)
    New style Aluminium Chevy (LS1/LS6/LT1)

    But I would have to agree. In order to really tap this power effectively, in a boat especially, you would want to convert to a much larger Berkley style jetpump. which removies the high RPM requirement.

  5. #5
    Vern's Avatar
    Join Date
    May 2005
    Grand Haven, MI
    Exactly ... I have had a few full size (18 - 20 ft) jetboats with V8s and would have to ask why anyone would want to do this??? You can buy a nice older V8 jetboat for $6000 USD, so why bother with a S-D conversion? You actually would not want a big block V8 in a 15 foot boat anyway ... it would not be stable and would be out of the water, porpoise, etc, place a tremendous amount of weight and motor torque on the S-D hull that it was not built for. If someone really wanted a fast V8 jetboat, find a good tunnel hull or gull-wing hull jetboat, mod the V8 a bit and you will have a very fun fast boat for far less money than trying to convert a S-D jetboat.

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