Call up Skat Trak or Impros and ask them. They do custom pitches to help give you what you want. I just received mine but haven't put it in yet. I have some motor mods and he sent me a solas concord, 13/19 repitched to 13.5/20. I also have an Adjust a thrust pump cone going on with it.
I have the rogue big air intake, rogue intake manifold spacer and polished the intake runners, 5 degree timing advance and synthetic oil. I see 68 on the stock speedo. I saw 62 stock. I see 61-62 on a $90 gps and have out run 2 brand new 06 GP1300R's on the top end, in smooth water. So I really have no accurate speed # to go off of. What was the problem with your impeller? Did it gain you any speed? The holeshot sucked? What about midrange? Did it just not pull the rpm's? The stock impeller is pretty good! Was your 13/19 box stock or did they tweak it? I'm putting on the Adjust a Thrust with it so I can tweak the rpm's the way I want.
Originally posted by AaronC: I have the rogue big air intake, rogue intake manifold spacer and polished the intake runners, 5 degree timing advance and synthetic oil. I see 68 on the stock speedo. I saw 62 stock. I see 61-62 on a $90 gps and have out run 2 brand new 06 GP1300R's on the top end, in smooth water. So I really have no accurate speed # to go off of. What was the problem with your impeller? Did it gain you any speed? The holeshot sucked? What about midrange? Did it just not pull the rpm's? The stock impeller is pretty good! Was your 13/19 box stock or did they tweak it? I'm putting on the Adjust a Thrust with it so I can tweak the rpm's the way I want.
My 13-19 is "blueprinted" and "race finish" by Dave at Impros. I did not tested with the freeflow and first waterbox modification. I will test the 15F this weekend but with the stock Impeller.
My ski was doing "as stock" only 60.5 GPS. With the 13-19 was 61 MPH, but like I said before, the holeshot was not good. Now with the freeflow let see what happens.
To gain speed, you'll need a taller impeller, more RPM, or both. If you're motor was stock then that's why you didn't gain much top end and lost on the bottom. The solas impeller is grabbing more water than the stocker and putting a bigger load on the motor, bogging it down. You need more power with the taller prop. The stock prop is very well rounded and gives an excellent holeshot with motor mods.
Today I tested the 15F, the riva freeflow gaves a noticeable holeshot and top. The ski top speed was increased by 1-2 MPH. Before the freeflow it was around 61 MPH, Now 62.3-62.7 GPS. The ski hoeshot is better also. Now I'm thinking of installing the 13-19 prop. I also made the first Waterbox modification,recomended by Riva
I tested my 13.5/20 out yesterday, and I like it a lot. The holeshot seems the same by feel but the midrange to top end acceleration has improved A LOT. It looks like 1.5 mph at peak speed but it charges pretty hard to top speed.
I'm glad to hear you gained some power in the exhaust. I ordered some flexible hose to bypass the secondary waterbox. I plan to modify the primary waterbox in the offseason and modify the exhaust manifold.
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