04-08-2013, 06:16 AM #1
Need your opinions on my cavitation
Ok, so with a speedfreaks impeller tuned to my ski, I had no cavitation on launch with my stock grate. I have an 84mm nozzle in now. I think it is a little to big. I turned around and mount an R&D grate (completely siliconed) and I have some cavitation at launch. I called R&D they told me its because my pump mount is not sealed. I said why does the stock grate not cavitate? He said the stock grate is much more aggressive. My cavitation is only out of the hole and maybe to about 10 mph. Seems to me thats when the grate would have little effect as the ski is not moving.
Ok, so my thought is would putting my 82.5mm nozzle in possible remove the cavitation?
Thoughs or explanations would be helpful.
04-08-2013, 07:35 AM #2
R&D takin some stabs in the dark.
I noticed a little bit of cav with the trim tabs adjusted right up. No doubt i will have to ditch the grate once I start putting some decent power down.
04-08-2013, 07:52 AM #3
Do you have a smart phone? If so, download "Logworks" app from Innovate. Its free. Then, compare acceleration rates before and after changes. Having a small amount of cavitation is not always a bad thing......sometimes.
Last edited by 1tommygunner1927; 04-08-2013 at 08:23 PM.
04-08-2013, 09:25 AM #4
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04-08-2013, 09:31 AM #5
I have a g-meter for my road car. not waterproof but maybe I'll take a chance. What about the exit nozzle at 82.5mm?
04-08-2013, 11:24 AM #6
04-08-2013, 11:27 AM #7
04-08-2013, 06:40 PM #8
I have been chasing cavitation for years off the line for racing, too big a nozzle/to small a nozzle, carbon ring, Bellows, drive-shaft carrier bearing, prop nose cone, tail cone,
what works for one might not necessarily work for others,
you have to start at a base line, and only change one thing at a time, and keep notes, try different grates with different nozzles,
different prop pitches if you have them,
If you are not racing why worry about hole shot cavitation?
04-08-2013, 06:57 PM #9
Just kinda weird that a grate change would cause cavitation. You would not think that a grate change would affect hole shot. When I think of grate change I always think how it is going to effect top speed, rough water hook up and handling, not hole shot.
04-08-2013, 08:36 PM #10
One major cause of cavitation is a poor seal around the ride plate and pump shoe area. Following the manual in applying sealant is not good enough. All the voids (of the RP) around the pump shoe sealing area should be filled with sealant and along the sides of the RP as well. A whole tube of 5200, or similar will be needed to do this right.
A proper alignment where the hat is square to the carbon seal is needed as well as the proper tension of the bellows to the hat.
The R&D intake grate seems to add some cavitation on its own.......
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