Thread: need insight...
05-19-2007, 07:36 PM #1
today was the first day of racing for region 8. I ran supercourse. the weather was around 60*, water about 50*. 1-2ft chop, in the bay. At first my ski was cutting out after a couple minutes to the point that I was stranded with it, having to get it back to shore and disconnect the battery to reset it. I unplugged the cat temp sensor, and that problem seems to be ok, but my biggest issue was that my boat was only turning 64mph. I have 21hrs on it, a PPK, 1200 grate, dplate, jims skegged FF plate, 87mm reduction nozzle, 14/20DF trued by IR, and I removed the jetworks mod prior to today. I was running faster when my boat was completely stock. My only guess is that the DF is a bit too steep for the stock motor, even with the 87mm nozzle. Would this be the majority thoughts? when I called IR, I explained what was done, and the guy told me 14/20 trued, balanced, and race finished, and a 87mm nozzle will bring the rpms up. I was ready to order a prop that was correct for my ski, not necessarily a 14/20, maybe a 13/19, but that was the guidance. What should my next step be? stock prop again? or will I be able to install an EFI controller to compensate for more RPM gain. Also, could I be running in a lean state because of the lack of EFi controller and the dplate mod?
As always, thanks for your help.
05-19-2007, 08:39 PM #2
So what your saying is that you ran 64mph in 1-2 foot chop? What was your rpm? I would get the EFI controller and a PET 2100DX tach to check rpm and have your stock head milled to 150 160 psi.
Last edited by WATER WOODY; 05-19-2007 at 08:41 PM.
05-19-2007, 11:01 PM #3
To accurately gauge engine and ski performance you are going to have to get out of 2 foot chop, and then use a tach like Woody said.. If you were doing 64 in 2 foot chop on a gp, my hats off to ya.. That sounds very fast to me for those conditions on a gp..
05-19-2007, 11:20 PM #4
- Join Date
- Apr 2006
- South MS
You need to find some smoother water to test mph in.
Are you measuring speed with a gps ? The stock speedometer can be way off, I've seen mine read 144mph
I think the easiest way to gain rpms on your ski at this point would be to remove or open up the stock air box and add a EFI controller then it would turn the 14/20 fine. With the efi controller -That opens the door for future mods like milled heads, and reeds ect...
05-19-2007, 11:58 PM #5
there is no better prop than a 13/19 for racing. Period end of story. Save that steep wheel for smooth water.
05-20-2007, 06:37 AM #6
do they have a 13/19 for the 05's and up? it would have to be a dynafly depitched. i trust joe on this one
05-20-2007, 09:17 AM #7
Ronn - I use a garmin eTrex.
I was thinking a 13/19 from the start. Everywhere I researched prior to my prop, was that the 14/20 drops alot of r's. I am running stock class and there isnt alot of ways to regain the loss of rpms. I can and will be adding an EFI controller, any recommendations about which one? I see Riva, R&D, and Advent. Advent looks like it is for the older GPRs, prior to EFI. I assume RIva's since it seems everybody runs them. I am also putting my jetworks mod back in today.
as for 64 in 1-2ft chop, I hit 64 on the back straight, but some of those boats were sailing past me, like I was on a VX110. I should mention, that I was the only one in novice stock, and was put in with expert, pro-am, pro, and limited and open. I wasnt basing my performance on hte other skis, but not happy with my own skis lack of hooking up. I had some porpoising issues, shimmed my tabs down to help with that, but it didnt do so hot, and I left a box home with my stock plate and stock sponsons, so I was stuck with riva sponsons which I am not so fond of anymore.
I saw alot of hidden mods on skiis, and the tech area didnt check anything but safety issues, I was really thinking of having my heads done, if I can raise to a 150-160psi stock head. Can that be done? I dont want to put on rivas, or aftermarket, because then Id get bumped to limited, and theres no way I can compete with those boats without taking out a loan... lol. Maybe Jim can work em?
05-20-2007, 09:21 AM #8
I will do some more searching on the forum and decide on an EFI controller, hopefully someone can chime in on the pros and cons of the controllers to help me in the decidion.
05-20-2007, 09:59 AM #9
The GPR is really hamstrung by the stock rules, but kudos to you for giving it a go! I don't believe the EFI controller is stock class legal, which is stupid because you can rejet carbs to your heart's content. You must run flame arrestors of some sort, though, so going open or Ross' sonic booms are out. Put the JetWorks mod back on, install a 3 degree keyway, and run only a single layer on your head gasket (starting to get into the gray area of cheating there). Make sure you're using 93 octane! Remove the siphon tube from the reduction nozzle and fill the hole with JB Weld, along with the visibilty spout hole. J-gap your plugs.
05-20-2007, 11:57 AM #10
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