JDM motor is USDM 03 wrx ECU information is making me crazy!
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This is a discussion on JDM motor is USDM 03 wrx ECU information is making me crazy! within the Builds forums, part of the Tech & Modifying & General Repairs category; Hello everyone! Been a long time since I have been here, looks as though my post count was reset and ...

  1. #1
    Registered User Spencer3636's Avatar
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    Apr 2009

    JDM motor IN USDM 03 wrx. ECU information is making me crazy!

    Hello everyone! Been a long time since I have been here, looks as though my post count was reset and most of the projects I was watching are all but gone...

    Either way I am here for some info from the knowledgeable.
    My Car: USDM 03 WRX

    The end of my motor: Bad tune + time = broken ring land

    What I got: A JDM Ej205 ODB2 motor with less than 35k

    Now before everyone starts posting about how I should have just gotten a 207 or just did a hybrid, or a v8 spec C cause there semi closed and better and yada yada I didn’t. This is the plan for the time being eventually I will pick up a blank 2.5 and start the long process of a super build, but that will be a long process and would like to be able to just cruise around in my car while that is happening. Back on track!

    What I think I Know:

    I need a JDM V7 of V8 ECU to control the AVCS (also a wiring kit, got that all covered)

    Conflicting information on if these ECU’s will talk correctly to the US ODB2 plug in (Smog, I know Cobb doesn't support JDM)

    My stock ECU will work but AVCS will not and from what I have heard, if it’s there don’t waste it because AVCS makes a nice difference!

    So here are the questions:

    Motor is JDM ODBII with AVCS. Ok I need a V7 or V8 JDM ECU to run the AVCS system now the question is V7 or V8 JDM WRX only? Will either of these support ODB2?
    Are there other options for ECUs? Forester? STI? (Are they all drive by wire?)

    I am just having issues finding capabilities with ECU’s

    If I can find a damn V7 or V8 and they do not support ODB2 I presume I could get my car fully tuned on the JDM so I can take advantage of AVCS and have a base tune done on my USDM for smog purposes, (TGV CELS pulled and compensate for the new compression etc) but obviously I would enjoy a simpler route.

    For the closing information on stuff that affects the motor here:
    Cobb high flow down pipe 3” to back
    Perrin fuel rails
    Over kill injectors
    255 walbro
    Over sized top mount intercooler
    Catless uppipe
    ACT clutch lightened flywheel

    So any information on what I can do here would be awesome, I know there are a million other things that I “Should have done” but we will save that for my new future thread on my monster build at that time I will be sourcing tons of information. For now I’m looking for what I can do with what I got.

    Thank you!!!!!!!!!!!!!!
    Last edited by Spencer3636; 04-24-2013 at 09:24 AM. Reason: Title edit
    Carpe Diem!

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  3. #2
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    May 2012
    im curious as well, ive bought a jdm 205 with no ecu for my03 wrx i want avcs but sounds like a massive pain to get it to work. i could buy a jdm ecu but it would run like crap because theyre tuned for ~100octane(ish) and i live in the absolute least tuner friendly state of arkansas. cobb is the most reasonable distance. cobb no do jdm. -_-

  4. #3
    Registered User Spencer3636's Avatar
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    Apr 2009
    Yea didn't get too much information out of this as you can tell. I will do my best to fill you in on my findings and presumptions. I again encourage the knowledgeable to correct me where I am wrong.

    JDM EJ205 used in JDM WRX wagons 99-01 then used in 01 - current all JDM WRX
    Has a compression ratio of 9:1 as opposed to USDM 8:1
    Has AVCS, mine also has TGV (rather amazing how they stuffed all of that on there) a MY00 - MY??? JDM thing?

    I Can only presume that any of the 01-03 JDM ECU's will work maybe even the 04???

    01/02 A4SD501A (MT/AT), A4SD800A (MT/AT), A4SD900A (MT/AT)
    03 A4TE000A (MT/AT)
    04 A4TE200A (MT/AT)

    I Was also told that the ADM (Australia Domestic Market) WRX's also utilized AVCS, if that was the case the following ECU's would presumably work

    01/02 A4SE700I (MT/AT), A4SE900I (MT/AT)
    03 A4TE0000 (MT/AT), A4TE001I (MT/AT)

    That last part might just be a bad assumption or the information on what year they started to use it is wrong...

    Getting the AVCS working is easy once the correct ECU is sourced. In my case the wire harness on the motor showed up relatively unharmed, enough so for me to do a little custom chop and re-wrap. At that point you will just need to run wires from the engine bay to the ecu, IAperformance makes a harness that is plug and play. Depending on the ECU you might just be doing a little repining of the TGV sensors or doing nothing at all?

    Tuning can be accomplished VIA Romraider or such and in your case you could get an eTune in order to deal with the "Japan gets way better gas then us so we need a tune to run the crappy 91" or whatever the best you can get in your area since as you said there are no readily available tuners.

    You can also just plug and play the JDM motor into your ECU, you will still however need a tune for any CEL's also to make up for the different compression.

    Basically regardless of what route is taken a Tune is going to be needed.

    Another point with the JDM ECU is Smog. I have read that not all of the JDM ECU's will play nicely with our ODBII port that needs to be plugged in when smog-ed, but then I have also read that some do. So really this is where I am in the dark. I guess worse case is if you need to smog once a year just do a simple smog tune on your USDM ECU and plug it in before heading to the smog shop then swap back. Romraider I believe lets you set your smog meters to "Ready" so you don't need to worry about driving around to get them all set.

    This is all I can think of at the moment. If I remember more I will let you know. I just got back from a trip over seas so my project has been sitting dormant.

    It is highly possible this post is full of bad assumption and misinformation. But really the information on ECU's and motors and market compatibility etc. etc. etc. is kind of up and down.

    Carpe Diem!

    My 03 Bugeye is cooler than your mom

    Bugeye Mafia #222

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  6. #4
    zax is offline
    Super Modulator zax's Avatar
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    The benefit of the EJ207 is the cams, valve springs, valves, and forged internals. You should give two ****s less about the "semi closed" deck argument. The EJ205 cylinder walls are plenty thick and not an area of weakness at your level of power. I honestly would not deal with AVCS. The valve overlap will certainly help with mid-range torque production, but it's not enough IMO to warrant the disastrously tiring job of wiring in a new ECU or standalone.

    One option, I seem to recall, is to use the Carberry Rom to control the AVCS using the TGV signal output. Obviously you would need TGV deletes, but seeing as how you have a JDM motor, I don't believe you have TGVs anyhow!

    EDIT: NVM I see that you said yours has TGVs.
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  7. #5
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    Mar 2013
    Northeast Tennessee
    Is that the parts numbers of the ecu?

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