Tie the boat to a stump and it will illustrate what I am referring to.
GT
At some point, any pump will run out of water if not properly fed. Dynamic pumps are not known for their suction characteristics. I have seen that quote before, regarding how a jet boat will produce full thrust while tied to a stump. I am willing to bet that; if that test were performed with today's horsepower, the engine would just bounce off the rev limiter because the pump can discharge more water than it can draw in. Any pump system can benefit from increased inlet pressure. If the pump starts to pull the engine down, more work is being done. Then it becomes a matter of horsepower. Granted, I am not familiar with Panther or Jacuzzi axial flow pumps, common detailing techniques will still affect beneficial gains. If this were equipped with a Skat-Trak stainless impeller, it could be re-pitched to tailor its characteristics to the power curve of the engine. Unfortunately repitching a cast aluminum impeller is not an option. Regardless, I just can't buy into the concept of cavitating the pump to gain RPM.
The next thing I would focus on would be, should the OP be ambitious enough to pull his pump apart, is detailing the impeller. That will make a world of difference as to how the impeller will bite. I would thin and sharpen the leading edges on the back, or pressure side of each blades. Then thin and sharpen the trailing edges on the front of the blades. I would remove the radius where the leading edges intersect the hub so that the leading edges intersect the hub at a right angle. Be careful not to thin the blades too much towards their root to prevent cracks from forming.
I would then detail the bowl. Remove all casting flash. Sharpen the leading edges of the bowl vanes, again on the pressure side. Without seeing the bowl, I can't make a recommendation as to where material should be removed, but the trailing edges should be thinned and foiled.
Finally, I would assemble everything with the tightest clearance feasible.
If it was mine, I would remove the divider in the steering nozzle. If you don't want to remove it entirely, I would sharpen both the leading and trailing edges of that divider. Some will argue that it aids in steering, but I feel it is an unnecessary restriction.
I think a very nice job was done on the rock grate. I would still remove every other bar if you can't bring yourself part with it entirely. Although I would be more inclined to leave just three or even just one.
After looking at your pictures, should it be necessary, I believe it is entirely possible to make angle shims to be installed between the bowl and the nozzle adapter (droop) so the water isn't breaking over the bow like a super tanker underway full-ahead.
I have never seen a Panther at the races, but I believe that there is performance to be tapped.
Yours in max performance,
Joe
