05-10-2010, 01:18 PM #1
Thinking about some more mods...suggestions?? 03 GPR.
Hey guys. I'm debating some mods for the summer on my 03 GPR. I'm impressed with the overall top speed but would enjoy a bit more acceleration. It's hard to leave her stock when 90% of the guys I ride with are all on RXPs.
Right now it has a solas concord 14/20 pitched by Duke (I believe it's a depitched 14/20...memory sucks)
Jim's FF R&D plate
Riva 1200 grate
SHO steering nozzle
stepped stock sponsons
shimmed stock trim tabs
It's seen a best of 71.1 mph in cool temps with me at 190 lbs and a 1/3rd tank of fuel.
Now...what I want is to keep her oil injected for convenience and long days on the water w/ the fiancee where remote fills may be possible. I don't mind adding a little oil to the fuel to help subsidize the lack of lubrication from the stock injection issues. I also am a bit wiery of the riva fuel controller...seems they aren't the most reliable little boxes out there. So, I'm taking that into consideration.
Therefore, this is what I am thinking...
WFO's VF3 set up
R&D power plenum filter (or just the Riva/R&D plenum filter)
Jetworks mod (have some reservations here too...I'm in the mud quite a bit so I'm concerned about the valve getting gummed up and blocking flow to the waterbox)
OR throw those on with the stuff above:
have Jim cut the head for ~150 psi
Riva efi controller
Anyone have any suggestions for other parts or anything else? Again, keeping reliability is just as important as adding power/acceleration to the ski since I still do all day 2-up rides several times a year. Ski only has 58 hours.
Thanks for any support!
05-10-2010, 04:52 PM #2
premixing the oil isn't rocket science. 16oz of oil to 5 gallons of gas. If you're filling up on the water just throw measure out 16oz and put it in water bottles. Personally i use a pub glass as a measuring cup. Why take the risk with the stock oil injection if you're going to be in there anyway?
As for everything else, cutting the head is probably the easiest and cheapest way to get that boat going quicker. The riva controller is basically plug and play, and i've mounted mine inside my glovebox so i can monitor the lights and make sure its working properly. Yes i've heard of having issues with them, but i never have and usually it seems like poor grounds or wiring issues.
One thing you must understand is when you modifiy anything, usually in any way, you run the risk of it becoming less reliable. So you need to accept those risks when you start messing with stuff ya know?
So if i were you I'd cut the head and get a fuel controller and go from there. The jetworks is a great mod that works as well, but if you are in a muddy area then it might not be the best idea.
05-10-2010, 06:18 PM #3
The EASIEST way to make your ski fast is through WFO. The man knows his stuff. More importantly he knows what NOT to do. labor rates are good too!
05-10-2010, 10:02 PM #4
05-11-2010, 08:55 AM #5
Well, now I'm starting to think leaving it alone seems to be best. As much as I hear great things about WFO (was going to get his VF3 reed set up anyway), driving a $4k toy to Houston to have work done is not really an option....I'd rather sell it and get an RXP at that point.
I'm fully aware of premix not being rocket science....all of my previous skis were premix, and I have two 2-stroke off-road toys in the garage. It's just the simplicity of filing up any amount of straight gas I want, either on the water or the trailer and not having to worry about it period.
I would hope the ski would maintain a pretty high level of reliability with just a few simple mods. I easily had over 200 hours on my 85 JS550, the last 60 of them with a coffman pipe, PJS water box, PJS head at 180 psi, and a 44mm Super BN. It never missed a beat. Same with my X2...head, pipe, waterbox, 44mm Super BN. Both unported, which seems to be key on 2-strokes for reliability.
Anyway, thanks for the input. Maybe it's time to let the 96 XP and replace it with an RXP. Then I can leave the GPR for the woman to enjoy.
05-11-2010, 07:02 PM #6
05-11-2010, 07:40 PM #7
Duke is in FL and knows his way around the GPR's
05-11-2010, 08:51 PM #8
If I were in your position, I'd just gut the stock airbox of the screens and leave the top half off. If worried about water intrusion, you can leave the top on and drill lots of extra holes in areas hard for the water to reach. This is free and works better than any of the "filters" you can buy. I would also open up the cowl and hole saw the bucket for more air. Once again free. You could add the VF3's while your in there, then you could just about push a 14/20 DF on an 05+ pump. If you were still short on RPM's with that prop, you could j-gap and index your plugs and remove one layer of head gasket. (almost free) I think that would be the best bang for the buck from where you're at now. (2mph gain min)
05-11-2010, 11:37 PM #9
Your throttle bodies modified into a set of sonic booms like these usually give 80-90 rpm on top end with lots of low and midrange power gains also, without compromising any reliability. Works equally well with a bone stock motor or fully ported with all the mods.
05-12-2010, 12:12 AM #10
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