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Thread: Double Injector size question

  1. Default Double Injector size question

    Ok, I've seen where is says, you should keep your injector size to double or less. I assume, since I have a JDM 2JZ, my stock is 440cc injectors, I could run 850cc injectors. My question is how well does the MAP ECU run bigger injectors? Idle quality, control of injectors, etc. This is on a MAP Based 2JZ-GTE Aristo JDM ECU, and I plan on using the MAP-ECU onboard 3Bar MAP sensor to run the injectors.

    P.S. If I set the MAP ECU to run stock 440s, using the onboard sensor, can I just unplug my old sensor, and say cut the wire and ignore it?

  2. #2


    We can't help with a base table for a JDM with 850cc injectors but that is why we recommend no more than double injector size so idle, etc., is OK. Otherwise you run out of adjustment range.

    The MAP-ECU replaces the OEM MAP sensor so you wire the Green wire to replace it and either cut the MAP sensor wire or unplug the sensor. The JDM wiring diagram on the website shows the MAP sensor wire cut.
    MAP-ECU Support

  3. Default

    Ok, so I have the car up and running, stock 440cc injectors.

    When I wish to put in say 660cc injectors I just tell the MAP-ECU -50% fuel across the entire board? and everything else stays the same?

    I have another issue, that I'll search on and then post if I don't find the answer.


  4. #4


    Yes that is correct but we would start with -40% or similar to start with as it is unlikely to be linear. You should start with idle to get an idea of the change and go from there. Remember to disconnect the OEM O2 sensor and clear the OEM ECU memory when tuning otherwise the OEM ECU will use it to adjust AFR's as well and you will fight each other.
    MAP-ECU Support

  5. #5

    Default where can i get the map for jdm 850cc injectors ?

    where can i get the map for jdm 850cc injectors ?

  6. #6


    MAP-ECU Support

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