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Anyone with any experience on fuel use (gallons per hour) on rebuilt 8/92s in a 46 Bertram. The engines have 125 injectors and are I believe around 650 horse each. 1950 gives about 22 kts. with a full load. Thanks
Were those two strokes or four strokes? I know the 53 series were 2strokes and maybe the 71 series, but I do not know about the 92, which often were blown, intercooled and aftercooled.
The 8-92s are two strokes. Here's a formula you can use to estimate fuel usage at wide open throttle; multiply total horsepower times .06, so 1300 X .06 = 78 gph. At 1950 rpm, the 8-92s should be at about two-thirds load so 78 X .67 = 52.3 gph. I would bet that's a good guess.
For four-stroke diesels, you use .05 as the multiplier. It's amazingly accurate.
Chart I have from Bertram shows 871s and 892s, for the 892s at 1950 rpms, its quoting 54.2gph, and 22.3 knots. don't know what hp spec that was for though.
Great estimates, 50gph at cruise on a 52 Hatt with a flatter vee, so 50 is a good estimate on the deep vee bertram. Neat old boat, the 46, good luck with your classic.
Holy Cow Jelly that estimate is danm near dead nuts on for my 4 stroke 3208Cats. 26.78 gallons/hour verses Bertram's manual at 26 gallons/hour. Danm and damn again.
Detroit 8/92s 
