04-12-2010, 07:03 PM #1
- Join Date
- Mar 2008
- Perth wester Australia
Setting up a GPR for CC racing and rec riding
Hi all. Ive got a GPRSHO and im going to do some closed course racing in it. At the moment its running a SS800 grate and a IR style ride plate with stock trim tabs. The ski has decent top end and has run 82.3 MPH but im finding as soon as its not glass im struggling for hook up. The thing just bounces and bounces...
My initial thoughts are to run a auto drop nozzle to get the corner hook up better but as for the rough water hook up whats your thoughts? the ride plate has mega angle at the moment so im thinkin of either dropping it down or going for a stock ride plate. Also considering 0 degree nozzle?
Ideally id like to find a happy medium of hookup for racing, and top end for rec riding...
A couple of mates over in Perth have made their GPRs turn hard using the auto drop and relocating the steering cable mount closer to the nozzle to get move leverage on the nozzle, so im sure i can get that part sorted but be interesting to see if you think i can get decent rough water hookup with the IR plate on a decent angle or wether i need to change the plate and nozzle...
Any help would be greatly appreciated... and will hopefully speed up the "trial and error" process.
Thanks in advance
04-12-2010, 08:30 PM #2
I find it's hard to get the best of both. One thing you have to ask is do you want to win or at least be very competitive or do you just want to race and have fun???
I would loose the ride plate and go for stock since it works pretty darn good and a 1200 grate and sponsons..... at least a 3 degree or zero nozzle.
Racing is not about speed what so ever .....it's more hook up and rider ability. Dont get me wrong speed is needed to, but the other are more so important ....if your not hooked up then your just wave jumping..
There is more but that all depends on how much ya really want to change.
If ya want watch this video.....notice the others ski's and how they ride. Look at mine and where the water line is. I know it's a kawi and way differant but thats what your aiming for in a CC ski.
This was kind of a exhibition run...
You could also do this....
04-12-2010, 08:44 PM #3
04-12-2010, 08:51 PM #4
Thats some awsome riding J-5 !
04-12-2010, 08:57 PM #5
04-12-2010, 08:58 PM #6
04-12-2010, 09:04 PM #7
Yea pretty much along with some other stuff to the bottom....
04-12-2010, 09:08 PM #8
04-12-2010, 09:15 PM #9
- Join Date
- Apr 2006
- South MS
I am by no means CC Racer....but on my tripple I had basically your setup that you have the moment, but I also ran R&D trim tabs which are thicker than stock and cut them off to the same length as stockers.
I always ran them shimmed .150" in the front and .190" in the rear, even with the plate angle high it would handle decent. I also had beach house sponsons. This setup didn't really scrub much speed. It went a best of 89.3mph with this setup.
Now for better handling-
If I got to the water and it was rough day, I always kept .120" shims with me to put on the rear 2 bolts to drop the angle on the plate. This made a dramatic improvement in hook up. With the tabs shimmed and plate down it handled great. only about a 2mph loss on top.
Now I know this is not at all the type of hook up a CC racer needs more of a Rec rider. You could find a 3 degree nozzle and 1200 grate to make it better, easy to change.
04-12-2010, 09:20 PM #10
we are legal for Jim's races.
You need to focus on three very distinct issues... weight, hookup, and pump.
The sho engine is 100LBS heavier than a GPRXP, and somewhat nearly 150LBS heavier than a single piper. This alone is going to prevent you from being competitive without some creative thinking. You might consider putting things like the battery in the very nose of the ski, along with the IC and anything else of weight that you can think of. Lose every pound you can on that ski, and yourself. It's not JUST that it's heavier, it's that it's heavier compared to the length of the ski.
The hookup on the gpr is going to require a massive intake change from what is considered normal on the smooth-water queens on here. You will need a ton of hookup. A used pro-shoe system, would be a minimun requirement. A used Bullett-racing system would be better. Rius may be able to help you out.
Finally, the pump system is going to be very important to this thing. You will need to get something like a 8-12 vien skat 160mm pump, similar to what I've suggested on the SHO... DO NOT get the setback pump with the larger skat pumps. There are just too many issues with it. Otherwise, there are options to put in the SD RXP pump. Your cost will skyrocket no matter what you do.
All of that, and you might be able to compete...if you've raced before, and are a good racer.
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