7.0L EFI or 7.3L PSD for jet drive boat

Discussion in 'Jet Drives' started by aktmboyd, Mar 26, 2014.

  1. aktmboyd
    Joined: Oct 2013
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    Location: Kimmirut, Nunavut

    aktmboyd Senior Member

    Not that the stock inter cooler on trucks are inefficient on passing air, but they are. I was meaning inefficient at exchanging temp. The shorter the exhaust yes the faster the spool but also the less heat soak that the turbo endures, therefore the lower the charge air temp and then lower the egt's of the motor. And oh yes I want to be in the boat I love that turbo charged diesel sound. Have you ever been to a truck pull and have one pull by under load, with that sound bouncing of the grand stands and trees all around it's music to some noise to others. :D
     
  2. aktmboyd
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    aktmboyd Senior Member

    What truck are you running now.
     
  3. parkland
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    parkland Senior Member

    Yeah maybe for like a few seconds or a minute, not a long boat ride lol. ;)
     
  4. aktmboyd
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    aktmboyd Senior Member

    Anyways back to the boat, with you using one you have a guesstimate on it's weight. I have been trying to get a hold of the manufacturer but they won't reply to phone call or email.
     
  5. parkland
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    parkland Senior Member

    Theres several different models.
     
  6. aktmboyd
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    aktmboyd Senior Member

    O.k. Thanks for that I'll keep trying Lake Winnipeg boat works. I just want to try and get a hull weight so I can figure out how much the completed boat will weigh
     
  7. aktmboyd
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    aktmboyd Senior Member

    With the sound of the boat, my friend had an older jet boat I don't know the make but it had a BBC with up swept wet headers and it was loud at the dock but once under way it wasn't bad at all in the boat. So I'm sure my boat will be very much the same. Plus I can play with the length, diameter and even slash of the stack to minimize any drone if there is any.
     
  8. parkland
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    parkland Senior Member

    I think you'd be way happier with quiet exhaust.
    You'll be so close to the engine, that you'll hear it no matter what.
    Do you want to have a headache after going for a ride?
    I'd try to make the exhaust quiet, and the turbo loud.
    Loud turbochargers will sound awesome and not as annoying and loud as the exhaust note.
    Plus cummins engines exhaust don't sound nice like a v8, they sound annoying like a cross between a giant pissed off bumble bee and farting in a garbage can. Nobody is going to thank you for the exhuast sounds that thing gives off ripping through the water.
    And I bet you if you do go the open exhaust or straight pipe route, you will regret it shortly after the first ride you go on.

    If it was a race boat or fun toy, it would be different, but this is basically a fun idea for a general use boat, right?

    What about using a mudboat style drive?
    Much simpler and cheaper than a jet drive, and I think more suitable to your needs.
    Heres a page with a few pictures:

    http://blizzarddesigns.com/mudboat/mudboat.html

    I think basically, theres a u-joint at the transom, and the prop shaft can be lifted out of the water or pushed down, so you can hit rocks, logs, debris, without major problems.

    Just hook the engine up to the prop shaft without a transmission, use paddles to manuever backwards. Avoid the trans altogether. Just lift the prop out of the water to start it.

    Just use a prop that will run good with the RPM the engine can put out, avoid engine mods, keep it simple (stupid :) )....


    Look up mud boats on youtube, you'll see some of the abuse guys put those setups through, probably a lot better set up for you than a jet drive, and might yield a very useful boat.
     
  9. parkland
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    parkland Senior Member

    Also the stock cummins power rating would be loads for a boat that size, if you used a system like above, you could just match the prop to the factory engine RPM rating, have a fast reliable boat, without anything too expensive, and still probably be very reliable boat.

    I don't know what the mud shaft drive system would cost you, but I'll bet its loads cheaper than a jet drive, and probably more effecient and will last longer than a jet drive.
     
  10. aktmboyd
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    aktmboyd Senior Member

    I have been looking into steerable, tilt-able surface drives as well. Ones like DBD (too new and too expensive, I heard 12000$) and arneson, I never thought about running it direct and forgetting the transmission. The mud boat drives are very similar to the DBD's style of drive except they have a surface piercing prop like a true surface drive which the DBD's are not. You maybe on to something here. I have been emailing Claude at Exact-welding, out your way there and he seems to think they might be able to set a pump up to live happily with the motor. Now that's with the motor the hull, well that might be another thing. But I am still going to look into the mud drive. Thanks :)
     
  11. parkland
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    parkland Senior Member

    Yeah definately look into the mud drives, the only hull modification you'll need is a small hole drilled in the back. Plus theres lots of guys running them in swamps and stuff, so you know they are at least decent at dealing with debris.

    Jet drives waste power compared to propellers too, so the jet drive will waste fuel.
    The mud drive propeller should allow fuel effecient low speed operation too, I don't know if you'd get that with a jet drive.

    If you do manage to run into a bunch of rocks, the mud drive prop system should jar out of the water, maybe you'd need a new prop. This would be very cheap compared to replacing the impeller on a jet pump.

    It all boils down to what you want to spend, but I'm trying to imagine if it was me trying to build the boat you envision, and I think I'd run the mud drive prop, no trans, right to the motor. Simple design means cheap to run, easy to fix, and less to go wrong.

    The exhaust could always be changed later, just make sure you choose the right powertrain for the boat.

    I imagine a 5.9 cummins and prop should let you get some wicked good fuel economy at lower speeds, which is a nice if you need to go on a longer trip.

    Just imagine if this thing breaks one day, which it will, anything with moving parts will eventually break, how easy it would be to get a repair done on a shaft mud prop drive compared to a jet drive.
     
  12. aktmboyd
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    aktmboyd Senior Member

    Now we're getting somewhere in the beginning everyone didn't care much for the idea of this motor in my boat, but I know once hooked to an appropriate style of drive it will be nothing short of wicked. Economy when you need it and power when you want it.
     
  13. parkland
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    parkland Senior Member

    I don't think it's very practical, but what it lacks in being practical, it could make up for it with coolness lol.

    Another idea, see if you can get a dry sump kit for the cummins, and delete the oil pan. This would allow it to sit several inches lower in the boat, adding to stability.
     
  14. aktmboyd
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    aktmboyd Senior Member

    C of g for the cummins 5.9 is only 6" higher then c/l of crank. Just read that about an hour ago. So that really isn't to outrageous. With the motor on its beds in the transom is there really going to be that much difference then the twin out boards. I can't seem to find anything about that mud outdrive system that you sent the link to. It must have been a one of custom. But found another drive like the DBD out of Germany.
     

  15. shakescreek
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    shakescreek Junior Member

    I can't comment on the surface drives or the suitability of the hull, but I do have some experience with diesels and jets. I don't think you'd be happy with a flowpro behind a 5.9. A 3 stage flopro may hold the cummins at 4000rpm or so if you set the cummins up so it can rev that high, but that will mean you're cruise will be above 3000rpm,not ideal for a 5.9. Sure they will rev that high but are not efficient at those kind of rpm's, not to mention more noise and vibration. Engines always are most efficient near peak torque so best to set them up to cruise not to far above that point. Quite a few jetboats in this area running 5.9 cummins and they are all set up for full throttle around 2700 to 2900 rpm and cruise in the 2000 to 2600 range. Everyone of them that I am aware of is running a hamilton 274 pump, but big dollars for one of those. The only way I can see to make a 5.9 work reasonable well on the cheap would be to couple it to 2 smaller pumps such as the flopro, older multistage hamiltons,kodiaks, AT's, or berkelys. I know one guy that is running 2 AT 309's off of a single 572 c.i. gas v8 using a cog belt drive set up, and it works very well. Not sure if your hull would be suitable for that though, would be interesting to see a good picture of the bottom.
     
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