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  1. #1
    SJL Custom's Avatar
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    Anyone tried a Vortech SFMU

    Looking at the Vortech SFMU P/N 6X100-001. Looks like an all in one solution for fueling our skis. Comes with different pre-calibrated fuel curve rates and has an adjustable max and min pressure and adjustable rate curve as well. Just wondering if anyone has had any successes with this on their ski.


  2. #2
    Whats that whistling noise? jtskier11's Avatar
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    Quote Originally Posted by SJL Custom View Post
    Looking at the Vortech SFMU P/N 6X100-001. Looks like an all in one solution for fueling our skis. Comes with different pre-calibrated fuel curve rates and has an adjustable max and min pressure and adjustable rate curve as well. Just wondering if anyone has had any successes with this on their ski.
    Im sure that can be mated to work on the RXP somehow. But your probably batter off with a RRFPR. http://www.4-tecperformance.com/inde...roducts_id=703

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    SJL Custom's Avatar
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    The problem with a 1:1 RRFPR is that it will give you a rough idle and will not maintain a proper AFR all the way down to idle. The 1:1 is good for keeping within a 11.7-11.9 AFR on the top end, but as you break away from that towards idle you will become more and more rich causing rough idle. The Vortech SFMU has verying rates of fuel curves which allows you to keep a more consistant AFR all the way down to Idle. This single RRFPR is capable of doing everything the dual regulator high boost setup is available in the store.

  4. #4
    Site Admin Green Hulk's Avatar
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    Quote Originally Posted by SJL Custom View Post
    The problem with a 1:1 RRFPR is that it will give you a rough idle and will not maintain a proper AFR all the way down to idle. The 1:1 is good for keeping within a 11.7-11.9 AFR on the top end, but as you break away from that towards idle you will become more and more rich causing rough idle.
    Not necessarily true. When at idle or cruising (engine under vacuum) the fuel pressure is at stock levels. It's only under boost that the RRFPR increases the fuel pressure and of course it's only creating this extra pressure when needed. Idle quality does not suffer.

  5. #5
    ctriverguy's Avatar
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    Quote Originally Posted by Green Hulk View Post
    Not necessarily true. When at idle or cruising (engine under vacuum) the fuel pressure is at stock levels. It's only under boost that the RRFPR increases the fuel pressure and of course it's only creating this extra pressure when needed. Idle quality does not suffer.

    Jerry, what about when one uses larger injectors?

    wouldn't that create a rich scenerio at low rpms?

    Is there a one set ratio that works over the rpm range on Rrfp's?

  6. #6
    SJL Custom's Avatar
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    Jerry

    Is it not true that a 1:1 rrfpr only rises the fuel pressure at the same rate as the boost? That therefor would not change the lb/hr rate of the injector across the whole band when under boost. The only time it would change is as you said at vacuum which is minimal. If youre using larger injectors this would cause a richer rate than normal at idle and through out the range except at WOT.

  7. #7
    beachbum0286's Avatar
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    Quote Originally Posted by ctriverguy View Post
    Jerry, what about when one uses larger injectors?

    wouldn't that create a rich scenerio at low rpms?

    Is there a one set ratio that works over the rpm range on Rrfp's?
    With 50's and the Riva ECU the idle is fine. With the Rotax 8800 ECU and 60's the idle is very rough. That is one of the things that I did not like about Rotax 8800 ECU.

  8. #8
    SJL Custom's Avatar
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    The RIVA ECU is mapped for the 50lb injectors up to 13.5lbs of boost. So the fuel output is controlled by the ecu and not the regulator. I am refering to if you keep the stock ECU intact.

  9. #9
    Quote Originally Posted by beachbum0286 View Post
    With 50's and the Riva ECU the idle is fine. With the Rotax 8800 ECU and 60's the idle is very rough. That is one of the things that I did not like about Rotax 8800 ECU.
    My Rotax 8,800 ECU idles at 15 AFR with 65lb injectors.That is with the base pressure at 60psi on my RRFPR.I don't see how it could be rich and at wide open throttle I'm 11.7 AFR.

  10. #10
    SJL Custom's Avatar
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    Mitch

    How much boost is your ski running. Sounds to me that your fuel pump is running full open. Anything over 11psi when the RRFPR is set at 60psi and your pump is maxed out causing the lower AFR. The fuel pump maxe3s out at 71psi.

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