Re: alpha gen one impeller / water flow and gear ratio..
Thanks! I was under the impression that the gen 2 rives pumped a little more water. If anyone remembers seeing specs for a gen one drive or runs across them, I'd appreciate you posting them.
To be frank, I'm about to to convert to closed cooling (almost have the parts all together) and am wondering if I can get away without installing a hull pickup and belt driven raw water pump - use the impeller / pump in the drive at least for a while. My understanding is that it is generaly not able to supply enough flow with a 1.5 gear ratio. I have a standard alpha 1.5 gear ratio on the boat now, but alsi have a different drive with a 1.32 gear ratio I can put on. The 1.32 drive is an alpha one ss drive that has a CLE gear case, front entrance low water pickup and is a few inches shorter than a standard alpha. Most internal parts, including the water pump, are the same as for a standard gen one alpha it's mainly the cases a couple shafts and a couple misc. small parts that are different (shorter drive).
From the gen 2 numbers above, it sounds like it's safe to assume that the flow rate is reasonably proportional to verticle shaft speed over "normal" operating ranges, and I've noticed that with new impellers, my regular alpha drive with 1.6 gear ratio puts out less water than my alpha with 1.47 and that the shorty drive puts out a good bit more (all are based on how much comes out the exhaust at fast idle... I'll give it a try and see if it can keep up when running hard...
Time to get some work done so i can hit the water in the morning... What a gorgeous day out! Hope everyone gets some water therapy in this weekend.
