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  1. #1

    Join Date
    Sep 2010
    Little Rock, AR

    RPM and Boost down

    Took the ski out a few times over the past few weeks. The boost is down a few psi and rpm is down a lot. At the end of last season the ski would pull 8100 rpm no problem, at that time it would have 11 psi of boost and run low 70's.

    I first found a pretty bad exhaust leak on the manifold at the J pipe. I replaced that and it seemed to help some. I still felt like it was still sucking through a straw though. I have a X charger with a 4 inch custom cold air similar to the riva rear exit. I switched back to the riva 3 inch cold air and the problem got worse, even less boost and rpm's were down to 7200.

    The only time it felt half way like it did last season is when I pulled the seat off, the rpm's made it up too 7800 and I saw 10 psi of boost, the gps was reading 69mph. With the seat on it was on seeing 7400 rpm's. On this day I did have a stock prop in the ski, switched out the pumps to see if I had a prop problem.

    Could I have a supercharger problem? I'm seeing a small amount of oil coming from the inlet side of the blower and a small amount in my charge piping.

  2. #2
    Mod less, ride more! troyheb's Avatar
    Join Date
    Jul 2007
    Nederland, Texas
    Sounds like a combination of things. Oil in the charger is not good, and If you picked up rpm's with the seat off sounds like you still have a exhaust leak.

  3. #3
    Wheels-X's Avatar
    Join Date
    Apr 2011
    York, PA
    Yeah I'd absolutely get that charger out of the ski and look it over ya know? Check the oil seal for sure behind the impeller wheel if you have oil in the intake. Change it out to the Viton seals if thats leaking and check the S/C slip and all too. How many hours are on the X charger's components? Might just be rebuild time and for a catch can too

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