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Which would get better fuel milaege, and mid range acceleration

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Old 02-11-2006, 11:05 AM
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Default Which would get better fuel milaege, and mid range acceleration

Triple 625's on a drive with a tranny(no bravo drive) or a pair of semi staggered 925's and dry sump#6's . Boat achieves approx the same speeds, give or take a few mph. When cruising at approx 45-60 just curious what what yield better milaege, and better mid range accelaration. Thanks Jeff
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Old 02-11-2006, 11:07 AM
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Default Re: Which would get better fuel milaege, and mid range acceleration

my vote is twins
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Old 02-11-2006, 11:11 AM
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Default Re: Which would get better fuel milaege, and mid range acceleration

from our experience with trips.....i dont think ur gonna get good enough mileage with either set up for it to matter ................................
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Old 02-11-2006, 12:00 PM
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Default Re: Which would get better fuel milaege, and mid range acceleration

I would think you would have less maintenece and more reliability going with twinns. (1 extra motor could be more problems) I personally have never been a fan of triples. Having triples can't be comfortable to drive with 3 throttles either.
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Old 02-11-2006, 12:06 PM
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Default Re: Which would get better fuel milaege, and mid range acceleration

Will the boat plane with two out of three motors?
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Old 02-11-2006, 12:30 PM
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Default Re: Which would get better fuel milaege, and mid range acceleration

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Originally Posted by f311fr1
Will the boat plane with two out of three motors?
No problem. 70mph would be approx top end.
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Old 02-11-2006, 12:35 PM
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Default Re: Which would get better fuel milaege, and mid range acceleration

You will find that trips are not very fuel efficient since the center engine is really just along for the ride until you are looking for that last 10 mph. My buddy's 47 with 525s is great and runs an honest 90 but the center engine is basically free wheeling and throwing up a rooster tail until about 75. Then the tail flattens out and the rpms come more in line with the other engines. Usually at cruise of 60-65 the center engine throttle is about 2/3s what the outside engines are. And trips makes docking a little more interesting too
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Old 02-11-2006, 12:39 PM
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Default Re: Which would get better fuel milaege, and mid range acceleration

Oh, one other thing, if you go with trips make sure you have closed cooling, I know of quite a few cases where the center engine failed way earlier than the outside ones. Watching the water pressure on the Fountain it looks like the center engine gets some really disturbed water at varying speeds and conditions. Since the 525's have closed cooling it has not been an issue, but with a straight cooled engine I believe it is enough variance to cause isolated overheating in the center engine-possibly due to air pockets or aeration of the cooling water. At least a set of large sea strainers should be used to try and keep good solid water in the engine.
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Old 02-11-2006, 12:47 PM
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Default Re: Which would get better fuel milaege, and mid range acceleration

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Originally Posted by insptech
Oh, one other thing, if you go with trips make sure you have closed cooling, I know of quite a few cases where the center engine failed way earlier than the outside ones. Watching the water pressure on the Fountain it looks like the center engine gets some really disturbed water at varying speeds and conditions. Since the 525's have closed cooling it has not been an issue, but with a straight cooled engine I believe it is enough variance to cause isolated overheating in the center engine-possibly due to air pockets or aeration of the cooling water. At least a set of large sea strainers should be used to try and keep good solid water in the engine.
Great information, thanks Jeff
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Old 02-11-2006, 12:57 PM
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Default Re: Which would get better fuel milaege, and mid range acceleration

our cig 42 revo with makin about 525 hp x3 we didnt run over 3000rpms for about 5hours ish and burned up nearly 350gallons
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