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cats & turbo diesels

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Old 01-05-2008, 01:04 AM
  #21
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when you were involved with buzzi how did you guys deal with the gear selector foward neutral reverse apparently that's a problem unless i use a crushbox
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Old 01-05-2008, 02:43 AM
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they are making their own internals for the marinized Duramax, and they are holding up very well, can a gas 600hp motor run at wot for 2 hours, not a chance.
You're kidding right?

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Old 01-05-2008, 09:20 AM
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Two quick notes:

Buzzi boats ran crash boxes that were oil pressurized from the engine w/suction back to engine sump with the offset drop gears on the tail of them. If anyone else remembers when marine engines used to have the gear box mounted on the front of the engine ie Chris Craft/Paragon? Our boxes were like those just on the flywheel side.

Next, if you think Seatek's ran for 100 hrs or more racing your kidding yourself. Average Seatek race engines were what I called freshened every other race, 2 at the most.

Back in the day the story was the Gancia ran the whole season on the same engines, remarkable, no other UIM 1 boat could make that claim. I argued that point with Bonomi and Buzzi until I just walked away. In my mind it was a marketing ploy not a pactical claim. The same engines to them ment the same castings, crank, rods & pistons. Things like cam belts, rings, bearing, valves were all maintenace items - of course those needed to be changed!!!!

Even with that said, in their time they were technology superior to anything else in their CUI range. Alot of what they did wasn't new it was barrowed form larger engines and scaled down or taken from very small CUI gas engines - they just applied those concepts better because their business model was high priced engines to a select few. They never planned or wanted to build 250,000 of them per year.

I've spent millions of dollars and owned 2 fulltime dynos to do just those same things. Just because something runs on the dyno does mean it will run in real life. Dyno's are just a measure of output. How many of you ever used an electric dyno, most are the water dynos which are really recreational units. Electric dynos can drive the engine, load and unload in milli-seconds, you can replicate the loads a truck see while shifting gears and releaseing the clutch. We never did it well but you could have written a program to replicate racing and jumping off/landing waves. Allot of engines break on those dynos that would run great on a water model!

Duramax - it was said they fixed the psitons. Did they go 2 peice pistons or a dissimilar bonded metal?

As far as diesels the way to go, from a saftey stand point absolutely. From a costing standpoint, it has never paid off for smaller boats for the original owner. You don't use the boat enough to offset the additional costs. When your the second or third owner and you don't have to replace the worn out gas engines they you see a savings but on fuel prices alone you can't from day one.

In NJ, diesel costs more per gallon than premium gas, that to me is crazy!!!

Bottomline, I hope who ever is doing these Duramax's does finally bring the oil burners out of the dark ages!!!

Joe Gere
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Old 01-05-2008, 02:31 PM
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I have always wondered how the limited rpm band of diesel will allow the high speeds that a cat can run. I would think it is hard to gear and prop a engine that has 50% rpm of a gas engine. How do you get to 150 mph at 3-3500 rpm and stlll plane the boat? I will stick to my gas engines for now.
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Old 01-05-2008, 02:52 PM
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I have always wondered how the limited rpm band of diesel will allow the high speeds that a cat can run. I would think it is hard to gear and prop a engine that has 50% rpm of a gas engine. How do you get to 150 mph at 3-3500 rpm and stlll plane the boat? I will stick to my gas engines for now.
I always wondered the same until I see the overseas Victory and those other teams in which run Lambos or diesels....and those diesels run hard........ for example Buzzi...his race boats run hard..

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Old 01-05-2008, 03:49 PM
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Brad or lowblue320

How fast do your boats runs and with what gear ratio and at how many engine RPM?
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Old 01-05-2008, 03:52 PM
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Brad or lowblue320

How fast do your boats runs and with what gear ratio and at how many engine RPM?
should run good but wont know till a couple of weeks..
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Old 01-05-2008, 04:38 PM
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“Duramax” The new Diesel Warrior! Light weight, will rev to 41-4300 rpm but will it last at 750 hp and if so, how long?

Habana Joe is got it pretty spot on.

As for what race teams have accomplished, you must realize what is what so to speak.

Yes, a 1200 hp diesel does run great (for a short period of time) against a 900 hp gas engine. What else would you expect. 1200 vs 900, no surprises there. Buzzi typically held a MUCH larger margin than this.

As Hanaba Joe pointed out the diesels are not more reliable when tweaked either. Every time you tweak something, it is going to break, Diesels are no different.

As for RPM's and boat speed. Well that is why Haban Joe said HP is HP.

1,200 hp @ 3,000 rpm = a WOPPING 2,150 lbs of torque. Before everyone says oohhh and ahhh, look at what we have to do that big # to get the boat to perform.

For a Catamaran application: Overdrive the gear box by 1.75:1 and now we have 1,200 lbs of torque to the propeller.

Naturally Aspirated Gas engine, 900 hp @ 7,000 rpm = a merely 675 lbs of torque. Now we reduce this by 1.32 and we get the torque up to 891 lbs of toque.

A 300 hp difference equals a 309 lb of torque (per engine) difference in the boats.

Now the kicker.... Engine weight affects boat weight.

That 1200 hp diesel (SeaTek) will weigh 2000 lbs when it gets into the boat. Dressed Engine, not bare.

The 900 hp gas engine will weigh 950 lbs (remember no blower) when it gets into the boat.

So 309 X 2 = 618 lbs of torque advantage for the Diesel but it has a 2,100 lbs weight penalty over the gas.

Pleasure boating, and not such extremes with the power or the weight will makes things better and closer. But do you compare that 750 hp Duramax to a 525 Merc?
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Old 01-05-2008, 05:22 PM
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Thank you RIK!

Your right with our margins, the old Gancia with the small engines had 4 X 600hp ea =2,400 hp

It raced against gas boats with 2 X 850hp ea = 1,700 hp

We better go faster or hang it up!!!!

When we re-power Gancia with the twin turbos it was 4 X 900hp ea = 3,600 hp - funny thing was only maybe 8 mph faster, the boat was at it's limits

Thank you again RIK for your support!
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Old 01-05-2008, 11:25 PM
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then how do you explain a 46 skater(heavy boat)equipped with 750s seatek and arneson drives hits 101 mph???
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