I had an AT B- impeller in my pump. Spins about 5-5200 rpm on motor at the river.

I picked up a brand new berkeley C impeller off cl for 50 bucks.

My AT has always cavitated hard of I flat foot it from idle.. a lot of you have seen me do it.

I put this Berk in which is a smaller cut expecting some rpm gain and worse hole shot.

I gained about 2-300 rpm. But holy shit the hole shot is better than it has ever been. It'll pull to about 6k for just a second or so then load down.

It's a 200% improvement. And this is a stock non detailed Berk impeller.

My AT is stock s well but B1 cut it to a B- for me. It is set up at about .030 clearance front and back. About .025 radial clearance.

The berkeley was measured to have the same radial, but i didn't measure front to back clearance and you can see it is physically larger clearance. I'll measure after this vacation.

Any ideas why the Berkeley works so much better?