fuel consumption

[torcano]

I am thinking of upgrading from a 240 Sundancer (5500lbs) with a single 5.0L MPI Mercruiser with a Bravo III to a 280 Sundancer (8500lbs) with twin 5.0 L MPI engines. I currently burn 10 gal/hr at 3500RPM in my 240 Sundancer. Should expect to burn 20 gal/hr with the twin motors at 3500 RPM? Since the weight of the 280 is not 2x the weight of the 240 could the combined consumption of the twin motors be less than 20 gal/hr? Could I get the same speed of my 240 from the twins motors at a lesser RPM? In other words, is the RPM the sole determinate of fuel consumation regardless of engine load?
RK

 

[HT32BSX115]

Re: fuel consumption

It depends on how it's propped probably. If it's propped correctly, I'll bet all three engines will burn the same fuel at the same RPM. Propped correctly all three engines will be turning about max rpm at WOT..... so at 3500 you'll probably be somewhere around the same fuel flow. The 280 will not be running the same boat speed though.....

Maybe you should make the same comparison at the same (planing) boat speed (and the same BOAT) the 280 is a BIG boat. find someone that has one with the 7.4L single engine.

You're gonna burn at least the same or more per hour as the 7.4L 280......maybe not double yours but I'll bet it burns at least 7-8 gal/hr per side at a similar speed.