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  1. #1
    Vern's Avatar
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    How much speed will 2+ lbs boost add?

    I am debating about buying 42lb injectors and installing my Les Cooke A kit supercharger - I think this setup is very similar to the new RR SC impeller. My ski currently runs 75 - 76 mph at 8000 rpm with a stock SC and Riva Stage 2 setup, registers 7 lbs boost on my mechanical gauge. I think the A kit should add about 2, maybe 2.5 lbs boost and just wondered how much top speed / WOT rpm that might add? Anybody know how much speed or rpm they gained on top from switching from a stock SC impeller to a RR SC impeller?


  2. #2

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    About 1 mph you probably won't need the injectors until it gets down to 65 degrees unless you have cam or porting. It sounds like you are running stock ignition so you may have to tweek prop to stay off rev limiter.

  3. #3
    Vern's Avatar
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    Excellent, thanks Stan. Yes, still running stock ECU but have Skat mod pump and venturi rings, could switch from current 82 mm to 81 mm if I get on the limiter, or bump the 15/20 trailing edge back down a little too.

    For the injector swap, just remove the fuel rail and swap the injectors, or is it more involved? I would do it first thing on a weekend, so there (hopefully) would not be much fuel pressure in the rail? Michigan weather is unpredictable ... I might do them sooner rather than later just to be safe.

  4. #4
    Site Admin Green Hulk's Avatar
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    Take the connectors off the injectors
    Remove the two E8 torx bolts on the fuel rail and lift it up. The injectors will come right out of the intake manifold.
    Pry the injector clips out and remove injectors from the fuel rail.

  5. #5
    Vern's Avatar
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    Thanks Jerry!

  6. #6

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    When you remove the injectors from the fuel rail don't let the gas run into the intake manifold. The rr ecu will really wake it up if you want more.

  7. #7
    Jarrett's Avatar
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    Xpsteve showed me that you don't have to pry the injector clips off to remove the injector. Just squeeze/press the clip down towards the holder and it will release the injector without removing the clip itself. Wish I would have known that the first time I changed mine

  8. #8
    Moderator Franko's Avatar
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    You do have to pry the metal clips off that hold the injector to the fuel rail. The wiring harness gets in the way of re-installing these clips. I clip the zip ties that hold the wiring harness to the fuel rail to get it out of the way, then zip tie them back when you are done.

  9. #9
    Jarrett's Avatar
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    You're right. Had it backwards.

  10. #10
    Moderator Franko's Avatar
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    Jarrett, I can't believe you forgot about those clips.

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