Add it up for the year and compare it to the insurance bill.

I can tell you at WOT...

496 @ 425 hp 35.41 Gal per Hr
502 @ 525 HP 43.75 Gal per Hr
Closer to 19%

It seems to me that it should take the same amount of horsepower to go 38 mph with either boat. Therefore, all else being equal, fuel mileage should be the same. This would not be true if they were both going WOT. Here the 525 woukd burn more fuel per hour, and generally get less miles per gallon.

Yery good point. The 525 should have a bigger pitch prop and an XR drive versus the 496 smaller prop and an X drive if it is a default setup for each engine on the same boat. What were the props and drives on each?

I think there will be a slight difference at any speed no matter what only because they differ in displacement, and therefore demand placed on the engine.

A recent Powerboat article profiled 3 open-bow 20-something footers (all the same make and model - Nordic I think?), one with a small-block, one with a diesel, and one with a big block. The worst fuel economy went to the small block!

I don't know why you are asking, BUT assuming you are asking because you are making a purchasing decision that is driven by fuel economy I would have to say - who cares.

If it is a 10-15% difference over the course of a summer, and you burn 4,000 worth of fuel (I assume a long season in Mesa AZ), than that is only a 400-600 dollar difference and I think that most on this site will tell you that in the scheme of things that amount doesn't really matter. I am a BUDGET boater so take this for what it is worth....

I only carry liability. For instance, last spring I paid 6 grand to pull the deck, replace the gas tank, and the rubrail on the 22 Donzi. If I spent 6 grand last summer in fuel, I'd have had to have a great summer.

Not true.

1 different displacements
2 different powerbands that make different HP at different RPMs
3 different props
4 different drives (XRs rob more HP than other B1 derivatives, so they are going to rob mileage too.)

A 37AT with 496HOs/XZs/28P B1s gets a little more than 2 MPG AVERAGE over the entire RPM range on a trip.

A 37AT with 525EFIs/XRs/32p B1s gets a right around 1.5 MPG AVERAGE over the entire RPM range on same trip.

If all we had to do is put gas in our boats and they ran all season without high insurance, mods, maitenance and a pile of other things. Nobody would be on OFFSHOREONLY, everyone would be boating! LOL. Gas is still minimal at 3-4 a gallon.

I think we would all agree

By the way, the blue motor will run and last longer with care. Resale value and future mods will be better. Just my opinion

Quote:

Originally Posted by Rage

Yery good point. The 525 should have a bigger pitch prop and an XR drive versus the 496 smaller prop and an X drive if it is a default setup for each engine on the same boat. What were the props and drives on each?

Ok for the Ho = Bravo 1X with a 26 B
and for the 525 = Bravo Xr with a 28 B1
hope that help ....to understand