Is this Right?

[HAVASU DCB]

My 18' Spectra gets shitty mileage. I can go from bluewater up to the dam and by the time I am at the no wake zone back at bluewater I am out of gas. Its a 20 gallon tank. Is this right?normal?
just a bbc,berk.

[RiverDave2]

Is that at cruising speeds or Wide open?
20 gallons is an awful small tank for a big block.
The fuel economy sounds bad, but it doesn't sound that far off for a jet. Some of the jet guys are better suited to answering this then I am.
If I were you I'd look into installing two 30 gallon saddle tanks.
For anyone that doesn't know that can help HavasuDCB it's approximately 20-22 miles round trip.
RD

[Erik]

If the trip is only 20-22 mi. round trip, I'd day that you are right in thinking that your not getting the gas milage that you should. I have a 19 Hallett with at BBC & Berk jet, and if I run that distance I would expect to be down a third to half a tank by then & I also hold 20 gal. Thats assuming I only run in the 3000-3500 RPM range.

[rivercrazy]

My 21 daycruiser with a 454mag gets about 2.5 - 3 mpg at 3400rpm. Since the strip is about 20 miles for round trip your getting a 1mpg. Sounds low unless your running a very hot motor, cruisin at high rpms, or somethings amiss

[HBjet]

Is your fuel gauge working properly?
I have 2 (10) gallon tanks, and I run dual carbs. I can run up and then down the river a 3500rpm and I still have a few gallons left.
HBjet

[Boatcop]

It all depends on how you run, what engine/carb set up you have, pump output, jet-o-vator use, etc.
Boats fuel consumption is measured moe in Gallons Per Hour (GPH), than MPG.
Most big-block jets get around 8-10 GPH at normal cruising, maybe as high as 13-15 GPH at WOT.
When I ran an 18' Spectra (454+30 thou over, Holley 800, L88 manifold, Berkely Jet) we'd have to fill up the 20 gal tank about every 2-3 hours while patrolling the Strip, but that included a lot of idleing time.
Your situation doesn't sound too far off base.

[78Eliminator]

HBjet:
Is your fuel gauge working properly?
I have 2 (10) gallon tanks, and I run dual carbs. I can run up and then down the river a 3500rpm and I still have a few gallons left.
HBjetWhat!? You mean I am only going to be able to run my sled up to the dam and back before having to refill???? Ouch$$$$$$$$$$

[Skaterfast]

Bolt an outboard on there and you'll get better gas mileage on less horsepower while going a lot faster.HA HA.

[HAVASU DCB]

It is a 454/90 thou over. 750 holley, "A" impeller just thebasics no diverter. And I need a paint job in anyone knows anybody. Thanks for all the info!
RD2 when are we doing the Navigator?

[RiverDave2]

Pretty soon.. I'm buying a boat in a couple of weeks here so right now all of my money is going towards that.
When are we going to the river?
RD
[ July 24, 2002, 04:30 PM: Message edited by: RiverDave2 ]