Top Gun fuel burn good & bad
 

-Thought I'd share this data from last weekend.

We had some friends over and spent a couple days playing with my old straight bottom Gun. Tanks were empty, we put $400.00 (178 gals)in and ran pretty easy all weekend, mostly cruising 3000-4000 rpm with just a couple quick blasts up to 5600.

The 178 gallons lasted 8 hrs.

22.5 gallons per hr for an old Top Gun with 700 hp blower motors. I thought that was pretty decent for an old 12,000 lb sled!

What are others with similar set ups burning for fuel?

Kurt

Ran the Cig F-2 in the key west poker run two years ago & got 1.4 mpg @ 75 mph avg. 108 Gal for the trip from Miami to Key West. Our boat weighed about 8000 lbs in race form.

Twin step Cigarette. 525 efi's, Bravo xr's sportmaster lowers on 12 inch boxes.

'97 straight hull gun with 540HP modified 502(509)MPI's. My fuel gauge has been broken for several years so I have to keep very acurate fuel usage records to know where I am.
My fuel usage is very consistant tank to tank at 17-18 gal's per hour.

How many gallons do the straight bottom TG's hold? I thought there were two 80 gallon tanks, are they 90 gallon tanks?

I filled mine last weekend and they are around 90 gallon a side.

I always thought they were 130 gal's per side. I have never run it completely down to check but I have come close and that number seems to be about right.

I have an 1984 flat deck that I put new tanks in, in 2005. The company that I found that built the tanks was the original mfg. for Cigarette in 84, so they still had the prints for the original tanks. They are 131 gal. ea.

So how many miles you think you ran?

my 1997 has 110 gallons each side

No idea Tank. What's your fuel burn?

Should I think 22 gals/hr is good?

1998 Top Gun 127 gallons each side

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:drink:). 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.

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.