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  1. #1

    new RR impeller with stock injectors

    I think Jerry was going to try it with Carey's ski....

    Mark said the stock injectors could work at 228 horsepower.
    Riva dyno has the stage 2 working at 229 at 8000-8100rpm and 213 at 8150. If the new RR impeller adds about 12-13horsepower that would mean with a stage 2 at 8150 you would have 225 horsepower.
    That should work with stock injectors but I would think if your rpms were at 8000-8100 you would be in trouble.


    Mark posted this
    I have read that a four stroke engine requires around .5 to .6 pounds of fuel per horsepower per hour. If Bttek1 was spinning a 15/20 @ 8500 rpm that should require around 270 hp. (3) 50 pound per hour injectors @ 100% would be 150 pounds per hour. 150/270=.56 pound per hour per horsepower. That would seem about right I would think. If the stock injectors are rated at 38 pounds per hour @ .5 pounds per hour per horsepower ( the low end ) that would seem to indicate that the stock injectors are good for around 228 horsepower @ 100% duty cycle. Am I anywhere close to understanding this correctly?
    Thanks.


  2. #2

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    We are all curious to see probably 42lb will be safe?
    We'll try this once we see how many # of boost it really has?
    http://www.rceng.com/technical.htm#WORKSHEET

  3. #3
    Jarrett's Avatar
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    Which Mark are you talking about?

    Mark Underwood (rotax racing) told me the reflashed RR ECU/ported head/RR SC impeller/42lb injector setup has been dyno tested to be safe. Which seems to imply the same setup sans the ported head would be safe with 42lb injectors as well.

  4. #4
    Site Admin Green Hulk's Avatar
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    He's talking about Mark S

  5. #5
    Vern's Avatar
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    Jarrett, that is good to hear ... I have been wondering if I dared to run my current setup ... Les A kit, Riva IC, reflashed RR ECU and modded waterbox, stock longblock ... I think the A kit is very similar to the RR impeller. So, per Mark, my setup should be OK if I add the 42lb injectors? Is this with a piggy back fuel controller, or just the RR ECU?

  6. #6
    Jarrett's Avatar
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    Vern, as I understand its just the RR/RF (reflashed) ECU. I just ordered my injectors today. Guess I will be the guinea pig yet again

  7. #7
    EZ Dock of Long Island Shibby1485's Avatar
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    jarrett.... i'm headin down same path

    new RR ECU, intercooler, air intake, exhaust, Rotax racing SC impeller, and the misc odds and ends... this is basically what ur running, right?

  8. #8
    Jarrett's Avatar
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    Yeah, that's my kit. I've been really happy with the gains to this point. Hoping the injectors, RR SC impeller and skegs jump me up a couple MPH in time for MB2

    Oh and Mark@RR recommended doing the valve upgrade as well on this setup. I'm going to pass for now, but hoping I'm not sorry later. Looking into extended warranties right now

  9. #9
    EZ Dock of Long Island Shibby1485's Avatar
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    if u dont find nice prices on warrantees... get in touch with me actually, one of these coming weekends i'm gonna do a little Greenhulk.net BEST extended warranty promotion for our forum members for like a quick 2 day offer... i got alot of people that PM me asking for warrantees, so jsut waiting for the right moment i'll have time to sit and answer phone calls and take credit cards and enter all the VINs into the computer

    i'm tossing the valve job up in the air as well

  10. #10
    Do Work Son 05RXPnoob's Avatar
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    Quote Originally Posted by Shibby1485
    if u dont find nice prices on warrantees... get in touch with me actually, one of these coming weekends i'm gonna do a little Greenhulk.net BEST extended warranty promotion for our forum members for like a quick 2 day offer... i got alot of people that PM me asking for warrantees, so jsut waiting for the right moment i'll have time to sit and answer phone calls and take credit cards and enter all the VINs into the computer

    i'm tossing the valve job up in the air as well
    This could be something worth looking into

    Jay

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