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gph conversions etc.?

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Old 02-23-2011, 11:45 PM
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Default gph conversions etc.?

I was told as a general rule for EFI engines, divide the HP by 12-12.5 for gallons per hour at WOT. Carbed engines are not quite as efficient so divide the HP by 11.5-12.

So a single 500 EFI with 470/12 = 39.1 gph at WOT

and

Two 500 EFI with 470x2/12 = 78.33 gph at WOT

...just asking but would two engines be more efficient, therefore burning less gph?

...and is there a way to figure mpg at cruise?
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Old 02-24-2011, 01:19 AM
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Dude really?? C'mon w/ all these questions... Your basicslly asking the same things over & over!!! Your that worried about efficiency your looking into the wrong hobby.
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Old 02-24-2011, 07:39 AM
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454/502 blocks, N/A....figure 1 mpg with twins, 2 mpg with a single. It should be a little better but for budgeting that will be close....and I agree, gas will be the cheapest thing you spend on a boat. If those numbers scare you, look for one with a sail on top.
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Old 02-24-2011, 08:14 AM
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Gas, insurance will cost as much maintenance or vice versa as t500 said. And I mean maintenance that keeps it in top shape (no failures when taking it out) My numbers are .8-1.7 mpg twin 454 mags. About $400 a day in fuel. There is a passion for these boats that negates cost.
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Old 02-24-2011, 08:16 AM
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I would be more concerned about coming up with an average GPH figure. Or, GPH at certain RPMs.

As far as MPG, that depends on the hull. I could squeeze around 4 MPG @ 55 MPH from my last boat w/496.
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Old 02-24-2011, 09:58 AM
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For my first poker run in the Spectre, I had my friend with me that's a CPA. At lunch he mentioned that before the day was over we would have spent $500 on gas and oil. I told him that was the cheapest thing that could happen to us that day.
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Old 02-25-2011, 09:44 AM
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Quote:
Originally Posted by jmoore1225 View Post
Dude really?? C'mon w/ all these questions... Your basicslly asking the same things over & over!!! Your that worried about efficiency your looking into the wrong hobby.
I like to be 100% educated on ALL my purchases, I want to make sure I get 100% accurate information, the more people that chime in, the more accurate the info will be.

If the checkbook was unlimited I wouldn't be asking these questions and just write a check for a few million...
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Old 02-25-2011, 09:57 AM
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I run twin 540ci n/a motors,I would say at 50mph I burn about 15 to 20 gal per motor about 3400-3600 rpm as said before gas is the cheapest part of these boats my 2 cents
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Old 02-25-2011, 09:59 AM
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YOu can make the tank last a month or you can burn it in a DAY1 Its your choice on how much you use it.
GPH come on. The conditions vary way to much and the throttle position is what matters the most.
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Old 02-25-2011, 11:55 AM
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It varies by boat. I get better mileage with my 32 AT with twin 502mpi's than I did with my 28 Pantera with a hopped up 525SC.
That is at cruise speeds only. WOT, the AT uses more fuel.
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