Thread: got some gps numbers today ?
06-03-2006, 01:53 PM #1
got some gps numbers today ?
I have all the crap listed below..went out and got a gps run in..two differant riders..250lb rider, rpm's 7150 67.7 , air 90 deg,elevation 518 ft
185 lb rider ,rpm's 7140 ,67.7 mph..same day and time...trim set at N ,1up, and 2 up, always 67.7.....does this sound right ??? my prop has a small ding in it..i can post a photo if need arrises....????
06-03-2006, 01:58 PM #2
- Join Date
- May 2006
doesn't sound right to me. rpm's look good but 67 mph? unless u were in some serious chop.
06-03-2006, 03:10 PM #3
Does't sound right. Check Your pump shoe. Make sure it is recessed from the hull. If not pull it apart and trim the rubber plug kit so the shoe fits in a recessed position.
Look around for obvious speed theifs.
You should be at 71 at a minimum.
The impeller would be the first place I would look if everything else checks out.
Something is off.
06-03-2006, 03:18 PM #4
I am with Spud.
Pull the pump out and check the prop for damage and maybe check the pitch too. Pump shoe hanging lower than the hull will slow you way down. Same with the intake grate. It should be flush with the pump shoe.
06-03-2006, 03:56 PM #5
Thanks..i went thru the hull recall and got that straightened out,shoe sits up in hull,does not stick down. I added a 2 bar riva/r&d grate and noticed superb handeling but seemed slower on top...we were on glass to very moderate chop...my riding buddy has a modded gp1200r simular to my mods and he was at 67.0...very hot and 90 % humidity,8 gallons gas in ski
06-03-2006, 06:59 PM #6
yes, you are a bit low on speed.
[as spud said......]
06-03-2006, 07:20 PM #7
My GPRs always ran a little slower around Dallas than other parts of the country. Not sure if its the air or altitude or what. Even my RXP dropped from 76.x to 73.x recently in this heat.
Where are you doing your runs? At Joe Pool? If you go back on the Cedar Hill side past the bridge and under the train tressel back by Britton Park there is a nice, smooth, wind-blocked area where you can get your best numbers on that lake.
How much gas did you have at the time? What riding position were you in? Far back crouch? Did you try supermanning at all? Have you tried running with your trim all the way up, then one down, etc?
Are you going to MB2 next week? If so, there are several folks there than can help you, as well as, better climate for higher speeds there. You are welcome to follow us down there if you want. We have a convoy of about 5 skis so far.
06-03-2006, 07:22 PM #8
It's also surprising that two different sized guys got the same speeds. What kind of GPS are you using and were you watching the current speed or using max speed setting? And how long were the runs? The GPR needs some room to make its top numbers.
06-03-2006, 07:27 PM #9
What pitch did the impeller start out at? Was it a 13/19 that got repitched? If so sell it on Ebay. If not send it to Impros or Island and have it repaired. You can get a lot of repitched 14/20's on this board. 14/20 is the right hub design for that impeller with the pump you are running in your ski.
I've got a 14/20 repitched for 75$ but it is more of a 1200R impeller. You need something in the neighborhood of 14/21.
That ding will rob you blind. Think of the turbulence at 7000+ rpm's
06-03-2006, 07:29 PM #10
I hit 67.7 mph on my 2004 with intake grate and ppk only! I would say something is wrong!
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