I agree with you glen about how the berk pretty much comes in ready to go and parts and what not.
Lets start to modify here and there.
First the impllor.
Cuzzi has 5 blades over Berks 4.
I remember the Cuzzi having a smaller exit side on the impellor which to me can only mean more pressure.
5 blades means more bite
Yay or nay .....
-beerjet-
In general a 5 blade impeller works best for hole shot and 4 blade impeller is better for max top end (you can liken these to propeller design ie 3 vs 2 blade). There's a billet 5 blade impeller available for Berk but there again top speed is scrubbed off a bit in favor of low end performance. Heres a curve, A Drake pump has a three blade impeller, and when Turbine was developing their SD-312 they also experimented with a 3 blade design and found it wouldn't produce acceptable PSI.
The look, shape, feel, inlet angle and approximate size of the intake up to the 6 3/4±" impeller mouth is uncanny between the two jets(STD berk and jac WJ).
Compared to a Berkeley, the WJ impeller has a similar inlet blade angle. The WJ blades are slightly longer, but flatten out and narrow slightly more toward the exit. The flatter exit angle of the blades brings the outer shroud and the exit hub closer together, but the difference appears to be made up in overall larger exit diameters when compared to it's Berkeley equovolent.
The Bowl is the weakest link compared to a Berkeley, I don't have any actual numbers, but the bowl has less potential for volume. The exit side of the Bowl is actually the true nozzle of the pump, often refered to as the cone. Inside the cone is supposed to be a 1.5" round piece of aluminum with a bolt attaching it to the end of the bronze shaft support bushing. The Round Aluminum piece subtracts area from the nozzle exit which is 3.350", giving it the same cross sectioninal area of a 3" nozzle. It seems to be popular to remove this piece, but keep in mind, removing this piece makes the nozzle 20% large in area which is like changing a Berkeley nozzle insert from 3.125" to 3.49" nozzle insert.
In the end, in stock form they perform approximatley the same. The Jacuzzi seems to require less maintance, no rope packing to leak or go bad, no gaskets (except for the intake), the plastic wear ring takes the brunt of the wear, Solid Bronze bowl support bushing rarely needs replacing or shows any real signs of wear, Thust bearing is sealed on both ends of shaft and doesn't require drive line yoke to seal front, inspection cover is large enough to throw a cat through and is build very strong....
I'm sure theres more, but i have to get some work done now
