Top Gun fuel burn good & bad
05-30-2009, 01:59 PM
#11
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05-30-2009, 08:07 PM
#12
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I don't know (either question).
I always thought fuel burn per hour is kind've pointless since you have idle time, non-boost time and boost time and it could change all the time. I always thought miles per gallon would be a bit better of an estimate.
I saw on some thread sometime ago someone had an 800hp blown motor on a dyno with a fuel meter. It burned a gallon a minute at WOT.
So I always thought, with my small 525's with the baby blowers, if I used this measurment as a guideline it would be conservative. So I figure if I ran at around 60 mph and went off the Gallon per minute measurement, it would roughly equal 2 gallons per mile (gallon a motor). And it would all equal out in the end with idling time (less fuel) and bumping the speed up and getting into the blowers (more fuel).
So with 180 gallons or so you get 90-100 miles (or so
). Which is kind've backed up when we run a Twin Step (better fuel economy w/525EFI and TS) to Key West from Miami. 180 miles one way and can do it on one fill up (one way) with 210 gallons of fuel running around 70 mph (average). So he's getting almost twice the fuel economy but since I'm being super conservative (mile per gallon) I'd say he's actually getting 1/3 better fuel economy in reality. Because in all reality I'm probably actually getting a bit over a mile per gallon between both motors.
It makes sense to me and seems to work out well when I'm averaging fuel to put in and where we're running too (i.e. to the islands 14-20 miles out and 14 - 20 miles back). But then again, I run the boat pretty conservative and try to stay out of the blowers which of course helps fuel economy.
I always thought fuel burn per hour is kind've pointless since you have idle time, non-boost time and boost time and it could change all the time. I always thought miles per gallon would be a bit better of an estimate.
I saw on some thread sometime ago someone had an 800hp blown motor on a dyno with a fuel meter. It burned a gallon a minute at WOT.
So I always thought, with my small 525's with the baby blowers, if I used this measurment as a guideline it would be conservative. So I figure if I ran at around 60 mph and went off the Gallon per minute measurement, it would roughly equal 2 gallons per mile (gallon a motor). And it would all equal out in the end with idling time (less fuel) and bumping the speed up and getting into the blowers (more fuel).
So with 180 gallons or so you get 90-100 miles (or so
). Which is kind've backed up when we run a Twin Step (better fuel economy w/525EFI and TS) to Key West from Miami. 180 miles one way and can do it on one fill up (one way) with 210 gallons of fuel running around 70 mph (average). So he's getting almost twice the fuel economy but since I'm being super conservative (mile per gallon) I'd say he's actually getting 1/3 better fuel economy in reality. Because in all reality I'm probably actually getting a bit over a mile per gallon between both motors. It makes sense to me and seems to work out well when I'm averaging fuel to put in and where we're running too (i.e. to the islands 14-20 miles out and 14 - 20 miles back). But then again, I run the boat pretty conservative and try to stay out of the blowers which of course helps fuel economy.
Last edited by thisistank; 05-30-2009 at 08:20 PM.
05-31-2009, 04:06 PM
#13
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59-60 mph cruise @3500, old straight bottom 38 with Chief 800s. 13,000 pounds full.
1.2-1.25 miles per gallon. Hering 16 inch diameter, 5 blades. The tanks hold 130 gallons each. Kurt, set your GPS trip to 0 on the next fill up.
1.2 mpg is better than a 30 foot fishing boat with twin Yamaha 250s, that cruises at 32 miles per hour.
1.2-1.25 miles per gallon. Hering 16 inch diameter, 5 blades. The tanks hold 130 gallons each. Kurt, set your GPS trip to 0 on the next fill up.
1.2 mpg is better than a 30 foot fishing boat with twin Yamaha 250s, that cruises at 32 miles per hour.
