 Detroit fuel consumption
As a general rule, you can calculate fuel burn on a Detroit 2 cycle with the following formula.
8ozs per hour per HP
twin 450's = 900hp X 8ozs or 7200 ozs/hour at 100%. Divide by 128ozs. to change to gallons = 56.25 GPH at 100%.
I believe you will find your "normal" RPM and cruise speed will be closer to 65 or 70% not 85% so your fuel burn should be about 36 1/2 GPH.
No matter what a lot of Detroit people tell you, these motors should not be run close to max. RPM. Typically, a 2300-2350 RPM motor is happiest and will live a lot longer running at 1900-2000 RPM than it will at 2050+. Also, make sure your motors will turn up close to the reccommended maximum RPM with a full load. If they don't, find out why. Without going into a lengthy rant, if the engines are running properly, with 100% no load RPM, and the bottom is clean, your props will be the first place to look for more or fewer RPM.
Capt. Bill Hadley
United Yacht Sales
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