cummins jet boat

90dodge

90dodge

Always Broke
I'm tossing between ideas for what kind of project I want to start this summer while I'm working, and a jet boat has been on the list for a while for something I always wanted to build. Not necessarily a diesel, but I like both, and it would definitely turn a head.

Has anybody seen a 5.9 cummins stuffed into something like a Taylor or Tahiti jet boat? I feel like if the weight can be taken, everything else can fall into place. Air/water intercooler, marine parts, etc.

Just throwing out an idea, I'm happy to hear anyone's thoughts. I just feel in this area a diesel jet boat would hold much more value than just another bbf/bbc jet boat. Especially with all the oralers drinking in the coves in northeastern Oklahoma. LOL
 
I've been wondering the same thing for a while . I think it's a game of effective pump parameters and rpm .
 
Hamilton makes proper jet pumps for diesels, id have to call and see if they can fit one on a smaller boat.

I think any pitch jet can be made for a little extra money.

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i would be worried about the RPM range. Unless you are wanting to build a screamer. Effective Jet boats in my limited knowledge like a 4000 window of rpms to work with
 
Sounds like an awesome ideal to me. What about a 4bt to cut down on the engine weight some.
 
I don't think i could get a 4bt bought worth the money. For what i could buy a 5.9 for anyway.

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I know you could get a 6bt cheaper than a 4bt the weight difference between the two iirc is about 300 lbs. In a boat that is a good bit of weight.
 
Ya its a big difference, especially in one of those smaller boats. Lol

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I just looked up the weights and it looks like a cummins will be about ~300 pounds heavier than a complete BBC.

Cummins- 1000lbs
Complete BBC- ~700
 
the guy was a big bowfisher, and he was going through 502's like I go through socks, and would go offshore, and stack big sharks up like cordwood in the boat, then haul butt back to land.
 
mo'butta_02_1.jpg


This is the kind of boat I'm talking about. :rockwoot:
Just an attention ***** while pulling into party cove. LOL
 
WUnderwood said:
I rode in a 6bt airboat, and the results were not very good, just a FYI
Click to expand...

Altered Diesel Wurks built one that works quite well..

[ame="http://www.youtube.com/watch?v=rdCP8Ai7eBU"]http://www.youtube.com/watch?v=rdCP8Ai7eBU[/ame]


Wish I had some videos on the water to post for you
 
torque would def not be an issue, but rpm? I am sure you could pick it up with gearing, but still a relatively narrow band. Flame suit is on, how about a cvt setup so you got the torque out of the hole, but gain rpm to the jet after you are out of the hole.
 
WUnderwood said:
I rode in a 6bt airboat, and the results were not very good, just a FYI[/

Had to be specific set up. Me and a buddy built a 6bt twined airboat it does everything great. Runs dry as long as we want, increased fuel mileage from 4mpg with a BBC to 11.5mpg calculated usage. Increased our cruise speed by 15mph and that's with more weight in the hull. I'd say ours was a total success. To the op these are the results we had. Although its a airboat not a jet boat you can see the marked increases we saw over the BBC. As far Rpms our cruise rpm were able to take a dramatic decrease 1500 rpm and still perform at the levels above but the motor was still built to touch the upper Rpms if needed
6yvyme9a.jpg
a pic I took setting up duck blinds in the south Texas marsh
Click to expand...
 
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I have a few videos of the boat running real basic before I got a go pro but they show how easy the boat ran dry. Problem is I can't seem to get them posted on here
 
Have a Dmax motor setting in a 19 foot jet boat now , it bolts in like it belongs , the weight for complete duramax engine is 50 lbs more than an iron head BBC. I was ask by one of the boat magazines to get this project going , it’s getting close , but no picture are allow before publication
I am using 9. ¼ AAA Dominator impeller which is normally used for a 2500 hp Blown alcohol engine That pump will absorb 750 lbs as low as 3200 rpms . At 2200 rpms cruse it will absorb 550 lbs torque the efficient would pick up greatly. Looking at a 502 BBC vs a 500 hp Dmax the fuel efficient preliminary results are a 60% reduction in fuel at cruse and 40 % at rated power
The problem with a Cummins is too high a center of gravity for a ultra-low profile boat

I am currently designing a program for a major boat builder build Dmax motors for jet boats and bigger boats. Its comprises of cylinder head program, a cam design and raised compression to close to 21 to 1 , the hp rating for continues use is 500 cruse and 600 max power
 
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I was "into" jet boats for quite a few years. The key to matching an engine and a jet drive is knowing the power curves for both components. You want to match the pump to take full advantage of the HP that the engine can offer.

Most Big Block gasoline engines in hotrod jet boats spin impellers in the range of A, A/B, or B impellers. The impeller size is typically matched to the HP curve of the engine. These jet drives eat POWER, not necessarily low rpm torque, although there have been guys who have used overdrive boxes and underdrive boxes to move the effective power curves around for their respective engines.

As Greg describes above, you would need a very large impeller (AAA, 9-1/4 is extremely large by most hotrod boat standards) to take advantage of the relatively low rpm curve for most diesels.

Steve
 
Oh, God. Looks like I'm gonna have to clean out the shop and rent you some space, Juanathan.

You are gonna have to top the 502 Mercury Bret and I put in his old jet boat. You'd better be able to hit 70 mph in about 3 ft to do it. LOL
 
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