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Stepping up injector voltage

Discussion in 'ECU's, Electronics, and Tuning' started by K2e2vin, Dec 31, 2008.

  1. K2e2vin

    K2e2vin Senior Member

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    I asked this question on OneCamOnly.org but didn't get any responses, hope someone here could help:

    Quick overview on the next setup I "worked out";
    RDX secondaries, TL1000R primaries(~225cc@3bar), injector drivers(with another circuit to select injector bank), hydrogen injection(in non-VTEC mode) and dry nitrous(100hp, activated only when in VTEC and TPS=>99%)

    I have a multiple questions concerning:
    A.)injector response time
    B.)wattage the injectors can handle
    C.)what levels to use(PnH signals)
    D.)other methods to control the injectors

    A.)Increasing fuel pressure helps with atomization, right? I was thinking of jacking up fuel pressure to 4bar(about 60psi), but not sure if the injectors could respond fast enough. I've seen that Honda 240cc PnH injectors can respond well around 290µsec with a injector driver and 420µsec without one(numbers from Injector-rehab) but most of them don't have the pattern I want or are too expensive. Plus, I already have those injectors which are saturated.

    At 4bar, would a typical 500cc saturated injector respond under ~1000µsec? I need the fast response time due to the stage injection setup. Also, anyone know someone that could test response time(both opening and closing)? I know Injector-Rehab doesn't....I already asked.

    B.)Due to the dual stage injection setup and higher pressure, I want to run injector drivers and set them up for p/h, something like a 3/1 or 2/1 open/hold current setup....only problem is getting over 1a from the injectors. This would mean I'd need to step up the voltage.

    Assuming our regular saturated injectors open with 1a current at 12V, would it be safe to assume 12W per injector? This would also mean typical PnH injectors run about 48W peak then drop down to 12W.

    Using Ohm's law, presume our current injectors at 1A=12V*/12ohm. I plan on trying to get only about 3a tops of the saturated injectors, so 3A=V/13ohm, V=39. Thus, we'll see a 3A*39V=117W spike with a 39W hold current. Would this kill the injectors? Would running over a certain voltage kill the injectors(how high should I go)?

    C.) Also, it's possible to run lower peak and hold currents. I've seen 2/0.5 used also; this would allow lower voltage to be used(26v) and lower wattage. This would bring it closer to the levels of the PnH's with 52W/13W. I know most places use current to compare the injector response, but should I focus on wattage more since the voltage can be change vs. conventional 12v? This would also help answer: the hold current is 0.5A, would this hurt flow because the saturated injectors normally open at 1A?

    D.) The primary injectors can probably fare well without the aid of the drivers, or at 4bar, would they(I still need response to be well under at most 2000µsec)? I could lower the primary rail pressure but I'd have to use a more intricate fueling system. Could I have the primaries wired straight to the ECU with a switched power supply and then the driver wired in parallel...or would this be too much load on the ECU?
    How I have the injector selection set up(on paper for those curious), is the injectors are activated just by powering up the injector drivers with a 5v signal. Both primary and secondary injectors are on during nitrous.

    For those curious about the voltage, I believe the driver transistor can handle up to 60V and 6A and the power supply is separate from the rest of the electrical system via a step up voltage regulator. For injector voltage(assuming injector voltage is a variable), it only occurs between the regulator and driver/injectors. I'm assuming the response time for the circuit would be faster than than a mechanical response time; so additional dead time caused by the circuit should be, I'm assuming, negligible.


    I hope someone could help me, thanks!
     
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