by Richie O » Tue Jan 09, 2018 5:37 pm
The reverse gears have different ratios. I had a 160 horse mitsubishi with a borge warner 2.57 input to 1 output rpm. When I stepped up the power I had to update to a heavier duty twin disk reverse gear. Over 210 hp the borge warners get eaten up. I went with a 2 input to 1 output ratio so I gained some shaft speed from that. I also had to have the wheel reshaped. It was a 22 inch, by 23 inches of pitch and they added ( bent ) 4 inches of pitch. Pitch is the length of travel the propeller would move forward with one rotation. So with one rotation I gained 4 forward inches of movement. Between the 2 changes it put the wheel where it needed to be to use the power I have. I have no experience with v drives, but the actual transmission ( reverse gear ) may be separate from the actual v drive. One other thought too is the turbo most likely will have to be updated to a different foot and or water cooled turbo. My turbo is a hx40 water cooled unit. Not all boat turbos have a water cooled hot side. Your looking at a pretty heavy priced change over of hard parts. I think the water cooled exhaust manifold is a cool grand. My water cooled aftercooler is 4k if I need to replace it. OUCH. Marine is MONEY.
1989 W250 727, 3.07 L/S, S300, P/S Intercooler, Stans exaust, Pump adjustments, 127k miles,297 hp
1993 W250 extended cab, rag, 4.10 l/s, 6x16's, HTT 62/71/14 piston l/p, Isspro EV series tach, fuel pressure, boost, oil pres, water temp, volt, pryo, 132k/ 301 hp
1992 W250 with NV4500, 3.54's, 16cm 60mm GDS H1C, ground stock cone, Isspro tach, pryo, boost, fuel pressure, slow, rusty, dented,180k