Mind blowing project ! Again, thanks for sharing !

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As far as the dyno, wouldn't have a L&S Propshaft Dyno been easier to set up ? Yeh, I know there is a reason, but wondering what that is. :)

you are the Tony Stark of powerboats. . . . . . :cool:





what is the drawback of going with a traditional style tie bar on the Arnesons? or is that just not do able in this configuration. . . . .


best thread on OSO . . . .

Does the fact that Mercury now offers a 6.7 Cummins package help your drive decision? I know you won't be stock by any means, what power level are you shooting for? Stay dry! We have another couple inches of water coming today here at home.

The top of an Arneson drive is really low. To put a tie bar across the drives it would drag in the water coming through the tunnel. You can build a stand on top of the arneson to get the height but it would have to be 20 inches tall. The problem with that is the leverage it has, the only thing keeping the arneson from spinning is the trim ram and all the load from the tie bar goes into trying to bend the trim ram. On a v-bottom it's fine, but not on a cat.

Well, I just burnt an hour going back to read about all the work and machining that went into the trans / drop box / drive install. Good lord, all that machining. Incredible.

So 729 hp per side was not enough or you couldn't find out because the drives were unsafe at speed?

That's why this was definitely a tough decision, I have an insane amount of time and money in making all the parts and putting them in that now I'm not going to use.

I was never worried about the safety, it is a big heavy 46 skater that does not run crazy speeds so it would be hard for something to cause enough of a problem to crash.

The 729 hp was just not enough hp even if the drives would have been straight. We are going to try to get 1000 hp continuous and 1200 for short duration.

Here is the design spec I want for the engines.

Cummins 5.9-6.7 size engine
Things I need:
3400 RPM continous for 1000 hours

1000 hp continous for 1000 hours

4000 RPM for 5 Min each hour
1200 hp for 5 Min each hour

I need the best fuel mileage I can get at 33-3400 rpm

A switch that has three power settings, a high hp setting,
1000 hp setting, maybe a 700 hp setting.

It would be handy to have a 20 sec high hp setting as high
as we could get using the parts that are designed/spec. for
the 1000 hp 3400 rpm normal setting. only to use a couple
times for shootout drag race

so it sounds like you need to get in touch with these guys with the billet block cummin's engines that made over 2000hp at the most recent Ultimate callout challenge from the other week

With Cummins and Duramax, you should be able to do custom tunes at the levels you want. On my LMM Duramax, I Have 5 settings that I can change on the fly with a key (Key so I can remove and leave it locked in the stock setting or in the anti theft mode of idle only):

My tunes are (Rear Wheel Numbers):

1: 346 hp / 638 tq
2: 399 hp/ 727 tq
3: 468 hp / 847 tq
4: 586 hp/ 1,106 tq
5: Idle only, 900 RPM Max

Im not too familiar with the marinized Duramax and cummins and whether or not EFI live tuning will work, but I would imagine that it would.