Someone will post the stock Berkley Chart for you.
You may run a search on it.
Sleeper CP
OK, I am putting together a new combo for the boat - but I don't know if I should treat the impellor like a gear ratio / stall combo in a car, or is it something different? If I get the projected curve, how can I tell what impellor would best suit the berkely 12-JC?
RPM HP TQ
2K 155 408
3K 239 436
4K 372 488
5K 472 495
5.5K 495 472
6K 501 439
Someone will post the stock Berkley Chart for you.
You may run a search on it.
Sleeper CP
you may want to post your boat specs and what you want to do with the boat.
I think you would be very happy with a MPD A impeller
It's a 21 foot Daycruiser'ishV hull - Use skiing, cruising and occasionally going fast.
If I read these right, if you make more torque you want a bigger impeller, A2/3/4 (or is that AB??) which acts like a low numerically gear and will give you a greater top speed (and vice versa), correct? I'm still unsure of how to get from that chart to where I need to be. I'm looking for someone to explain it to me.
It would almost seem I would want the C impellor for max top speed, but the A would be better all around? See I'm not understanding fully how it affects things...
Am I correct if I said the C would give me quicker acceleration but the A would theoretically give me more speed per RPM?
The bigger the impeller the more forward thrust that is created at a given RPM.
The C impeller would have to turn about 600 - 800 rpm more than the A to equal the same thrust.
big boat that pulls skiers = big impeller.
If your engine makes it's power at a higher RPM, you will need a smaller impeller like a "C"...in some cases being able to get to this power range will give you more top speed. Say for example that your engine makes 500 hp at 6000 RPM. With an A impeller you wont be able to reach 6000, so you wont be using all the available power, and your speed will be dependent on getting more RPM, which = pumping more water=more thrust...
Hope that helps