You can. But that doesn't mean it's worth doing. The major difference is the crank and cam triggers are totally different between the engines. Also the IAC valve is different and cannot be used on the other ECU. The IAC also mounts differently, which makes it harder to swap to a WRX ECU.While im at it....
Why CANT I use an 02-05 EJ205 ECU on a 92-96 EJ20g?
Really? That's not a great way to treat a new member that you know nothing about.:facepalm:
No I am not implying that.The reason this all comes up is because if I did the swap outright and merged the proper 20g harness with my current 03 harness and used the JDM 95 ECU everything would work fine....BUT it would not be OBDII compliant....so inspection FAIL. (2003 chasis)
I heard that you can swap the USDM 205 heads on and change to the USDM Intake manifold (which is not a direct bolt on) and possibly run the 205 ECU. But need more info on that.
Yes, you can bolt WRX heads on the JDM block and use the WRX intake manifold. But then you pretty much wind up with a USDM WRX swap, so why not just buy a newer swap in the first place?
Although the triggers are different, wouldn't the signal be the same?
So I would just have to rewire the harness' to compliment the trigger's signal.
No, the trigger wheels are different so the signal is different. I shouldn't of left out the wheel part in trigger wheel. I'm just stuck using megasquirt terminology. If you use the USDM heads this obviously wouldn't be a problem.
The 20g had two variation in the WRX alone...92-96 and 97-98...
So there are really only two harnesses I am looking at here. (keeping out the legacy and forrester)
I cannot agree or deny because I don't know much about JDM wiring, I would get a confirmation on that if I were you.
The reason I thought the USDM wrx EJ205 ECU would be a good fit, was because it is a COP system as well, same 8:1 compression, and OBDII compliant.
That is true, but there is a lot of work involved in the idea you have.
The process for wiring (if it would all work) would end up being a UDSM ej205 ECU to SAME harness--to 2003 TS harness--to EJ20g harness--to engine.
Yes, and that is a lot of work and research involved in that. Pretty much twice the work of a normal merge.
My easiest route would be a stand-alone or JDM ecu for wiring...
I just wish there were stand alones that were OBDII compliant.
(hondata has the ability to send and OBDII "ready" signal)
And a piggyback wouldn't work unless I solve the USDM 205 ECU issue.
Your easiest route would be to sell that engine and buy a OBD2 compliant swap.
"If you are thinking about getting a 02-05 WRX ECU to use with the engine and ECU you have, then I would suggest not doing that. It will be a lot of work and not worth it unless you have a lot of spare time and you get the parts for free." - bubba
Are you implying using two ecus at once?
Umm, who are you to say who to listen to? Judging by your join date and your post count it doesn't seem like you've been around long enough to post something like that.First off dont listen to anything anyone has posted besides Wannabe Wrx.
Information and parts for EJ20G motors are pretty hard to find, "don't listen" is pretty vague to say but i have a EJ20G motor and tranny and i can tell you it was very difficult to find the wiring harness. My join date and post count don't mean anything to me. I was on Nasioc long before RS25 due to me owning a Wrx. When i got rid of the Wrx i moved to RS25 because i own a 95 impreza. I read more than i post. Every time i see a thread about a Wiring harness for a EJ20G its the same. either no useful posts or no post at all. He wants to find a harness and i told him where he could possibly find it, I didnt start on a crazy tangent. I gave him what i have found and my results.Umm, who are you to say who to listen to? Judging by your join date and your post count it doesn't seem like you've been around long enough to post something like that.
Mostly I speak for myself, but I haven't seen any posts that I would say "don't listen to them" about. If you don't agree with what someone posts then explain why or your opinion means nothing.