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Raiding the Subaru parts bin (JDM 2003 EJ204 in a GF6)

12K views 50 replies 11 participants last post by  johnxx 
#1 ·
This has been about year in the making, but I have a terrible track record for completing projects so I didn't really want to share much until it looked like I had a good chance of getting it at least somewhat working. Well, about 9 months later than I planned that day has arrived.

As of earlier today I now have the EJ204 out of a 2003 (BL/BP) Legacy 2.0R running well enough to drive around in my 1996 OBS.
Here's a photo from "the good side" (where you can't see the giant rats nest of wires):


Engine management is provided by an open source engine management project called "Speeduino." Here's my totally hacked together testing setup:


Here's a video of (totally not) the very first start:
Raiding the Subaru parts bin: 2003 JDM EJ204 in a 1996 Impreza - YouTube
Yeah, that's a lot more like the 31st start.

You'll have to forgive me for starting in the middle. I'll fill in more of the back story on this as I have time to type it up, clean up the wiring diagrams and dig up old photos. For right now, I just wanted to share my results. I'm happy to answer questions.
 

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#32 ·
At some point I might switch to camber/caster adjustable strut mounts, but for now I have bigger fish to fry, like catching up on a lost year of road trips while the weather is still nice. :D I think I'm just going to put the re-wiring on hold until the weather turns crappy here. I can borrow my parents' garage for a weekend and do the wiring there.
 
#33 ·
Been roadtripping this all over the place and it's still a blast. It never left me stranded until the heater core died and leaked coolant onto the ECU board. Hard to blame the car for that, though. New heater core, blower motor and ECU board and it's back on the road.

For the tune, I corrected my injector dead time settings and rebinned by tables to get more resolution where I needed it. The car seems a lot happier and also the random stutter I had around 6k RPM is gone now. I still never did the rewiring work. :D
 
#34 ·
Cool thread. I'm constantly blown away by the ingenuity and the drive by members on this forum in achieving vehicle functionality when dealing with an older ECU architecture that doesn't seem to have a ton of support. Car looks great. I'm actually getting ready to install essentially the same suspension set up in my GC coupe that you have in your wagon. Nice build thread and thanks for the read. Sub'd for the rest of the story to unfold!
 
#41 ·
@scruff3333
I'm happy to take requests!

Looks like I didn't get a lot photos of the car during my travels. This one is pretty cool though:

That's from a rest stop somewhere near Hope, BC. My wife and I did a fun little 2 day road trip from Bellingham to Osoyas on the US side and then drove back on the Canadian side. Highway 20 is amazing, but the trip back on 3 was pretty as well.

I also drove out to Wyoming to stay with a friend at his cabin. No pictures of the car but I took a timelapse on the way out:

and another one on the way back:

(Youtube video compression does not like time lapses :| )

The car did not love performing at 6000ft. It was sad and anemic. Part of it was probably running without barometric correction turned on, part of it was the tune being crap, but I get the feeling that high compression engines to not like thin air. I can empathize though. I had barely started to acclimate to the elevation by the time I headed back.

After that I rebinned the fuel, spark and AFR tables, fixed my injector dead times, retuned VE and added baro correction (when I replaced the ECU board). Also I switched from MSDroid for my live in-car dash to RealDash:
(the "fuel gauge" is showing AFR, with 15:1 smack in the middle. The tune has been revised since then).
Yes, it's a rip-off of the S2000 gauge cluster. No, I'm not sorry. I have a sweet V3 UK cluster sitting around but it's waiting on my wiring rework and I've been lazy.

@6DemonBag
If you're switching from worn out stock suspension it's probably going to blow your mind. I've had no regrets at all with mine either in terms of ride quality or handling.
 
#43 ·
I ended up with the WR15 R/T springs with upgraded bumpstops. I'll be pairing them with koni inserts. Group n mounts all the way around. Just need time to put them together.
2pots, tits in my book. In fact I dont recall reading 1 bad thing about him anywhere .
Your car looks really ideal in my world. Looks like it sat great.
Keep up the good work.
 
#44 ·
I was thinking about something stiffer than the P11Ls (Tein coilovers were a thought, as were the WR15s) but I feel like the twisty roads around me are probably a lot closer to UK B roads than JP mountain passes. I was definitely eying Konis for a while, but the price was a factor and then the KYB lifetime warranty sealed the deal. I had them ordered in to an O'Reilly Auto 5 minutes from my house and if I have any problems I can get a replacement through them. On smoother roads (or with more tolerance for a bit more "road feeling" in your posterior) I bet the WR15s + Konis will be a brilliant setup.

And yeah, 2pot's incredible depth of knowledge and his participation in basically every thread about the P11Ls/WR15 RTs was a big factor in buying from him. When I ordered he sent me this absolute wall of text on parts to pair with the springs, part numbers, alignment specs, articles on GC chassis alignment.
 
#45 ·
Here's the non-update update: Just been driving it around for the last half a year or so. I finally have a house with a garage I can actually work on it in. I've been busy busy busy, but when things calm down a bit I hope to put it up for maintenance and finally nail a bunch of the wiring stuff I've been putting off for the last year or so. EJ204 has been pretty much flawless so far and has put up with a ton of my shitty tuning. :)
 
#47 ·
Swapped from the Speeduino to an ECUMaster EMU Black for knock detection and DBW control (among a couple other things). The Speeduino would still be sweet for a non-DBW throttle and it will get knock sensing via an add-on board down the road. I'll do a bigger writeup on wiring in the EMU Black at some point when the wiring is more final.
 
#48 · (Edited)
Car's back in the garage for hopefully the final round of wiring and some other nice upgrades. Goals this time:
  • Remove throttle cable and speedo cable (done!)
  • Switch to DBW throttle (new pedal installed! iWire pedal adapter plate fits perfectly)
  • Install UKDM cluster that's (hopefully) compatible with a 3-wire VSS (car had a cable speedo stock)
  • Run CANbus from the ECU to a microcontroller for logging/other fun
  • Wire up AVCS solenoids (Finally time to get that mid-range torque!)
  • Swap oil pressure sender for a proper sensor
  • Putting on a WRX hatch and STI spoiler I picked up cheap (I was gonna wait until it was painted, but storing it takes up too much darn space and I keep worrying about knocking it over and breaking the glass)
86457

^ Old and busted (mostly) ^
v New hotness (cable clutch and DBW in the same car :D ) v
86458


After this I'll clean up the wiring diagram I made for the EJ204<->EMU Black<->bulkhead harness and post that. It should be a good starting point for anyone who wants to use an EMU Black with any single-AVCS motor.
 
#51 ·
Thanks for the kind words. :) One of the things keeping me going is the knowledge (belief? hope?) that soon I'll be pretty much done with wiring forever. :D Then I'll get to move onto the fun stuff. I'm unreasonably excited about putting on that giant STI wagon wing and the v1-v4 bumper.
Anyways, images should be fixed. You'd think I'd remember you can't directly link to google photos after all this time, but I seem to keep forgetting. The pics this time aren't that interesting, but it was really satisfying to yank out the speedo cable and throttle cable and know they're not going back in.
 
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