Thread: Ride plate and wedge add 3mph
02-20-2007, 11:16 AM #1
Ride plate and wedge add 3mph
Here is what Group K had to say on their testing of the ride plate and wedge. So if skip was GPSing 68.8, then we're looking at breaking 71-72 for only $200. Although Harry did say that the boat they tested was running 66-67 stock.
Ultra 250 ...add 3mph
In the last weeks we have been testing with an Ultra 250 to be raced in the 6 Hour race at Lake Havasu on Feb 24th. Since reliability and longest possible fuel range are top priorities for this race, we did no engine compartment mods ... but found speed in the ride plate.
By the time we were done, our 4th version of the ride plate modification netted a 2mph increase (peak rpms were the same). We also installed the LX nozzle wedge to gain another mph on top of that. With the Stage-4 ride-plate mod, and nozzle wedge, the boat still handles and turns great. The elevated nose height of this setup makes the ride through rough water a whole lot less punishing as well.
With the reduced water contact surface area, it's reasonable to expect that high-speed fuel ranges will be increased slightly... but the 6-hour will tell us for sure.
The Group K Stage-4 rideplate mod is available for $140(3-5 day in-house turnaround), and the nozzle wedge is available from your Kaw dealer.... It's the cheapest 3mph gain you'll ever get from an Ultra 250.
Respectfully, Harry Klemm
Unless otherwise stated, responses to all forum posts are based on my personal experiences working within the PWC industry, and developing high performance PWCs since 1987.
Last edited by Group K : Today at 02:37 PM.
Last edited by 13xracing; 02-20-2007 at 11:20 AM.
02-20-2007, 12:24 PM #2
Can someone tell me where I can get directions on changing out the pump wedge. I want to see if I can do it myself. Roger
Last edited by rhorne1053; 02-20-2007 at 02:08 PM.
02-20-2007, 05:41 PM #3
quote=rhorne1053;219465]Can someone tell me where I can get directions on changing out the pump wedge. I want to see if I can do it myself. Roger[/quote]
Its as easy as 4 bolts. Take you less then 10 mins.
AAAAAAHHHHHH GOT MY PLATE FIRST. Off to Harry first thing in the morning. I was trying to keep it quiet a bit till it got back from GK.
02-20-2007, 06:03 PM #4
So, they are doing exactly what we have done to the Matrix, how much are they kicking the ride plate for their speed gain? That's a very simple do it at home job, I'm guessing it's a 4MM kick.
02-20-2007, 06:04 PM #5
This is fun!
You've had your ski about a month or so and looks like you're able
to add 5mph to the 68.6mph for less than $500! I bet this wasn't
the case with the SD's when they first showed up.
I'm going to have to start a spreadsheet with the mods, results,
costs, etc. to keep track of it all so I can see what I've got to do.
Let us know about that gas pickup, is Kawa leaving 5 gal? Does the
new one really change it? When does that buzzer go off? I haven't
hit it yet, I'm at about 1/4 of first tank.
02-20-2007, 06:05 PM #6
- Join Date
- Sep 2006
- S. Florida
$140 does seem a little pricey for this mod. I too am wondering what is really being done for the $140 price.
Skip, please take some before and after pics/measurements of the rideplate so we can get a better idea of what had been done to it.
the nice thing is I have Tom close by so i can use a gps (when I buy one) and his ski (if he keeps it stock) as guages for any of the mods I decide to do and see what if anything is improved by my spending.
02-20-2007, 06:32 PM #7
I bought a second ride plate. That way I have them side by side to compare and if I dont like it I can go back to stock. Cost a bit more but this early in the game its good to have a back-up.
02-20-2007, 07:02 PM #8
02-20-2007, 07:48 PM #9
an angle area is grinded down off the rear section of the ride plate.
In effect the ski at WOT is riding on this angled area and the nose is lifted up , so the ski has less wetted surface area.
They did this mod for the STX Di and the 12F and 15F, its a good little mod.
This is not something you can do yourself unless you have a machine shop and some good equipment.
02-20-2007, 08:06 PM #10
Skip, Thanks for the diagram. I am also thinking of replacing the impeller, just waiting, to see which one will be the best one, along with the ride plate and the wedge. Would it be better to just wait and do it all at the same time. I am not looking to be the fastest ski on the lake but I sure would like to have the fastest cruiser model. Thanks Roger
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