I have a 98 Shockwave 21LS. Its very similar to many other mini day cruisers out there and looks just like the old Eliminator Sport Cruiser. It has an 18 degree bottom, 4 full length lifting strakes, reverse chine, and a rounded keel. It has a Marine Power 454mag with a non set back AT-309 pump (it does have the deep mounting housing) with an A impeller. It also has a FTN Place diverter (3.125" nozzle) and their large rudder. It runs great and is strong out of the hole.
When turning hard at low speeds the pump will blow out if you give it WOT. I think this is due to the hull leaning and the pump sucking air. I installed a loader grate (two outside metal angle irons directing water flow to the upper part of the impeller) and this help quite a bit. However, it will still blow the pump out. Is this problem possibly caused by the turning fins on the intake? Is it a characteristic of an American Turbine pump as their intake is smaller than some other brands? Is there anything I can do to reduce or eliminate this problem? I heard DPS Inducer might help but is a little pricy. Any ideas???