Another Impeller Pitch question...

[dkello1]

2001 rx, and the 2001 gs... i want to get TOP SPEED with the stock set up motor wise. the safest thing i find myself wanting to do is give them both a greater pitched impeller. first i would like to know what the stock pitch is number wise... and how to tell via number which one is going for top speed and which is just for accelleration...


Guide me in the right direction for top speed on the rx as far as pitch NUMBERS are concerned.... the whole 17/22, 13/19 loses me every time.

past that and an intake grate is there much else to do without making serious adjustments to my motor??


thanks in advance! your knowledge always is helpful!!

 

[Dr Honda]

Adding pitch without adding HP may not do anything for you. If you want more speed without mod'ing the engine... then you need to increase efficacy at the pump. If you are focused on top speed, then try a Solas Concord impeller. (what ever pitch they recommend) The Concord impellers have a narrow hub, so they allow more volume, in turn, adding a little more pressure at the nozzle.

Last thing... don't add an intake grate. Most of the top loader designs will scrub a few MPH on the top, but they keep the pump loaded, and the hull planted. In racing, that will give a rider better lap times.

 

[dkello1]

gotcha, that makes total sense as far as the grate is concerned. and the concord sounds like a good idea i just didnt call them to see what the best option for speed is. i will get on it though! thanks!

 

[jwick86]

The only draw back of the Concorde is it is a tall prop to pull the correct rpm for a stock ski. Most skis with flame arrestors still can't pull the tall prop that they recommend for that ski. You'd probably be better off sending your stock prop out to get re pitched. The re pitch is much cheaper than a new prop anyways. Flame arrestors are a simple mod and require a simple re jet. No messing with the carbs every time you ride. This should be your first upgrade, then a prop IMO.

The numbers like 17/22 are the degrees in pitch on the prop. Take 17, this is the leading edge, which grabs the water first as it is entered from the intake tunnel. The 22 is the trailing edge, which takes the water passed from the leading edge. The higher the number, the more pitch, the less RPM. You can load the motor too much with too high a pitch and burn up a 951 or a 787. They need to spin at the right rpm. On my XPL, I've re pitched the prop 3 times to get the right RPM as my mods have changed.

The leading edge is the side that the shaft from the motor goes into, it takes the water first, also the smaller side of the "bullet" looking hub. The trailing is the back side, which threads into the pump.