Offshoreonly.com - TRS GEAR RATIO "Which would be the best ratio for 540 HP engine.)

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TRS GEAR RATIO "Which would be the best ratio for 540 HP engine.)

Hi I own a formula 311 1987 with Trs Drives and Borg W Transsmisions and i have upgraded my engines to 540 HP.s but only getting 69. MPH out of the boat with my previews 420 engines I was getting 57 MPH so I am starting to think they maybe something wrong with the gear ratio of my boat the 69 MPH speed was achived testing with 25 P Mirage blades at 4900 RPM,s and should go up to 52,00 any suggestions I feel something is not workiing correctly or substracting power from the end formula.

Any suggestions

A 12 mph gain for 240 HP is actually pretty good.

Labbing the propellers could raise your rpms 200-300 and get you over the 70 mph hunp.