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  1. #1
    skigolfnut's Avatar
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    Testing some new injectors and ECU questions?

    I was running lean with my roatax racing ECU and my 42's with the ET-137 set up,
    I put in a set of Bosch 50's and had to dial the RRFPR back a little, but it had good AFR's all the way to the rev limiter,
    I definately need to repitch the prop to bring down my rpms if I am going to use this set up,

    Next I tried a riva ecu set for 50's and a 8900 rev limiter
    I had to dial up the fuel pressure way high for it to be even close to 12.2,
    it would go 8800 rpms and 78 mph but was too lean in the mid range,
    I just don't understand why this one ran so lean thru all rpms?


  2. #2
    From everything I am seeing, these bike need at least 60s stock and 80s for any sort of reasonable ECU. 100s would be an even better option but you need full access to the fuel curves and a RRFPR to get the 100s to work correctly. It has everything to do with keeping the Duty Cycle below about 85-88% at WOT and the pulse width above about 2.5-3 ms on the very low power end of things.

    Without access to the data, you are simply guessing.

    Andy

  3. #3
    monaroman76's Avatar
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    Who raised the rev limiter on the riva ecu, are you certain only the rev limiter was raised without messing with the tune? I run a riva ecu with Bosch 48's. Idle is very rich no matter where my base fuel pressure is set, mid range and WOT are okay with base pressure at 44 and reference line connected. This is with 2rude.

    If your idle is not rich, it certainly doesn't sound typical of a riva ecu. All accounts of riva ecu and Bosch injectors I've came across say the idle is rich. This is due to Bosch injectors flowing better than the crappy riva ones it was designed to be run with. Perhaps the riva ecu has been reflashed for 60's or 80's??

  4. #4
    skigolfnut's Avatar
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    the guy that sent me the ECU is saying that maybe my external intercooler is not cooling enough?
    I am using the 08 stock one from seadoo, that came from an RXP-X--it has never let me down yet,
    and I am running Bosch 50's
    Last edited by skigolfnut; 02-04-2013 at 09:51 PM.

  5. #5
    warsawspeedfreak's Avatar
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    Jerry posted on this awhile back on an early vtech thread about how you cant just raise the limiter without adjusting the tune. Search vtech threads and you should find it. Sounds like a factor in your problem.

  6. #6
    imp0ster's Avatar
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    Quote Originally Posted by whittlebeast View Post
    From everything I am seeing, these bike need at least 60s stock and 80s for any sort of reasonable ECU. 100s would be an even better option but you need full access to the fuel curves and a RRFPR to get the 100s to work correctly. It has everything to do with keeping the Duty Cycle below about 85-88% at WOT and the pulse width above about 2.5-3 ms on the very low power end of things.

    Without access to the data, you are simply guessing.

    Andy
    This is what I don't get about your threads. We cannot get access to IPW modifiers. These machines absolutely do not need 60s stock since our AFRs are dead nuts perfect with 42's a 1:1 and CMD with many modifications without being near static.

    monaroman76 is absolutely right about Bosch. Very wide spray pattern, way more linear than others and the best atomization in a common injector. A 42 bosch is NOT the same as a 42 Lucas. I'd rather set my ass on fire and run around a bar for 10 minutes then run Lucas injectors in my ski.

    BTW it never hurts to find a shop with a sonic cleaner and an injector flow bench.

  7. #7
    warsawspeedfreak's Avatar
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    My opinion is a similar to monaroman 76. The riva would normally run fine on the 50s but since someone has been in there and raised the limiter, now the tune is not right, would be a good way to put it. If it came from a member here, most likely it would have been a vtech raised limiter mod. Maybe it needs fine tuning from vtech is all. I would find out who raised the limiter. that would be most helpful to push you in the right direction to fix it or at least check it. If your goal is only the higher limiter...consider a whole vtech reflash on the riva since its kinda screwed now...no?

  8. #8
    GasResearch-VT.SE's Avatar
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    And all injectors are linear: fueling, latency, resistance, hydro flow, pattern, piston depth?

    Just saying...

    You can spend a LOT of time tuning just for injector change.

  9. #9
    If an injector flows 10 lbs per hour at 10% duty cycle and 20 lbs per hour at 20% duty cycle, what is the fuel flow at 100% duty cycle? What is the fuel flow at 1ms pulse width?

    Andy

  10. #10
    GasResearch-VT.SE's Avatar
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    I dont know, you're the EFI expert... tell us

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