Raiding the Subaru parts bin (JDM 2003 EJ204 in a GF6)
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:
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.
Thanks for the interest! I just read the first 4 pages of your journal and holy crap I thought I was stubborn. I didn't know what I was going to do if the JDM engine I bought didn't start. If it dies now, at least I know my wiring and engine management setup is (almost) right and I can "just drop in" another.
Here's what's done so far:
- "190ps" 11.5:1 CR EJ204 out of a 2003/2004 JDM Legacy 2.0R (in quotes because I'm still running the 96 MAF intake and stock exhaust w/ original cats)
- Speeduino engine management (Totally reversible, wired in with two adapter harnesses: one from the engine to the bulkhead harness, one from the bulkhead harness to the 96-98 style ECU connector)
- 3.9:1 5spd out of a 2001 JDM Legacy (2nd gear should top out around 60mph :3 )
- Exedy KSB04 clutch
- ACT Streetlite flywheel
- PowerStop WRX calipers/pads/drilled+slotted rotors
- Facelift hood/headlights/grille. Depo clear corners.
- 10 years of "keep it on the road" maintenance
Ahahaha. Yeah, the wiring is suboptimal right now for sure. I need to clean it up, but I also want to do things like hook up the purge control solenoid valve so I can make the evap system work, hook up the cam triggers so I don't have to run it in "wasted spark" mode on COPs and eventually I want the AVCS hooked up and activated as well for that midrange torque. After a year of weekends working on this thing though, I *just* *wanted* *it* *running*. No AC or power steering right now either and honestly I'm not sure I'll ever get put them back on. The AC never worked in this car since I bought it in 2007 and running without power steering is not nearly as bad as I thought it would be.
So it's the avcs dohc version then? Are you going to get the avcs up to get its full potential? Why did you decide on not using a jdm ecu and just adding wires for avcs and dbw? I wonder if there is a model in the year range of those engines, that doesn't have immobilizer.
If it indeed makes that kind of power, would be a good upgrade for the sohc versions like the one in my 07. I swapped in a 2012 sohc from a super low mileage legacy, but if anything ever happens, I may do some swap things instead. My car is already dbw and maybe I could find a way to run avcs.
I've got a FEVER, and the only thing that can cure it is more WHP!!!
This actually gets back to the planning stage of the whole swap. There's very little English language info on the JDM EJ204 that I was able to dig up. EU and Russia got a downrated version (lower CR and ~165hp) but even that doesn't seem to get a lot of love. So, basically, I liked the engine, I figured I'd be pretty happy with 180-190hp with lots of revs but most of what I could find about it was mechanical info from jp-carparts.com (i.e., what part numbers it shared with other EJ20s).
So, why not go with a JDM ECU?
1) I couldn't find any EJ204s being sold with a matching ECU and I did not feel like chasing CELs on a CANbus ECU anyways.
2) I couldn't find any front cuts (even if I had someplace to put one)
3) I really had no interest in doing a whole-car harness merge: I don't love wiring and I hate taking interior stuff apart and the goal was for the car to be "down" for as little time as possible (ha!)
1 & 2 still stand. 3 is kind of debatable. The car ended up down for about 3 months in the end. I possibly could have found someplace to keep a front cut if I tried harder. Hindsight is 20/20.
AVCS and DBW:
I definitely intend to get AVCS going eventually to get that mid rage torque but really, the car feels pretty good without it. Except for right off idle and in the places where my non-existent tuning skillz are really letting it down it feels stronger than the EJ22E it replaced in every part of the torque curve. Up past 5000RPMs it just wants to pull. I haven't been pushing it much past that point because I'm finding that I have no idea what I'm doing tuning ignition advance and I'd like to not kill it prematurely. Also, with the COPs running in wasted spark mode, they're effectively at double duty cycle. Not a good recipe for longevity if I'm zinging it out to 7100RPM all the time.
On the technical side, as far as I understand AVCS fully retards the cam advance angle by redline, so I should have the same peak hp give or take. with or without it. Peak torque is probably slightly reduced and shifted to a higher RPM.
As for DBW. I would have really liked to run DBW but yeah, without the JDM ECU or a more expensive standalone it wasn't in the cards. I'll write a little blurb on my workaround and shove it in a different post so I can link to it.
TL;DR #1: You can run a DBC throttle body on a DBW manifold as long as you believe.
I'll be writing up some blurbs about how I got around some of the challenges I made for myself. Here's #1 on the DBW to DBC "adapter" I "made".
I knew going into this that the DBW throttle wouldn't work with the Speeduino and the DBC throttle body wouldn't fit on the DBW manifold. To work around that, I had a plan A and a plan B.
Plan B was to get another N/A phase II intake manifold, move all the necessary wiring over to it and drop it on. That manifold is sitting in my garage right now.
Plan A was to see how hard it would be to make an adapter plate that would bolt into the intake manifold and provide studs to mount a DBC throttle body.. Then I'd just find someplace to put a throttle cable anchor bracket. This was of course easier said than done for my (previously) non-existent fabrication skills.
By all rights I should have gone with plan B, but the same stubborness that got me through this project just wouldn't let me give up on that pretty EJ204 intake manifold and put an ugly EJ222 manifold on.
I'll write up the adapter plate in more detail at some point, but the short version is this:
- The DBW throttle body is much more compact than *any* Subaru DBC throttle body as far as I can tell. This means that the fine folks at Fuji Heavy Industries packed stuff around it in pretty close proximity. Test fitting an EJ18E or EJ22E or EJ222 TB in their intended orientation meant they were running into the fixture for purge control solenoid valve for the evap system, which I'm intending to use. Even if I wasn't though, the throttle cable would have been scraping across the plenum on the EJ204. Because of that, mounting the TB at a 15-45 degree angle only made things worse. Flipping it 180 degrees didn't help either (I can't remember what it was running into).
- Then I found out that if you rotate a DBC TB 90 degrees it will actually *just* bolt into the bolt holes for a DBW throttle body. And in that orientation the throttle cable will *just* clear the top of the plenum.
- So I made a prototype "adapter" plate that just has 4 bolt holes, a hole the same size as the throttle opening and a vertical tab to mount the throttle cable anchor bracket on. That is currently on the car.
- The current prototype "adapter" is made of plastic and the throttle cable anchor bracket is made of angle brackets from the hardware store for mounting shelfs. You can scream now if you want, but it'll be replaced with one made of CNC'ed aluminum before I take it on a roadtrip or idle it in hot weather.
- If anyone working at Lowes is reading this: I would love a sponsorship for this project. Get in touch.
- Just to anticipate one more question: I'm running the car off the MAP sensor, not the MAF so I'm not *as* worried about unmetered air sneaking in around the TB. The stock intake is there temporarily because I had it on hand. See above: I have so much left to do.
If you take a look in this slightly older photo you can get a better view of the visible part of the "adapter". Seems like I didn't take any photos of it outside the car. This is probably iteration 10 or so with the first several mockups made in MDF to gauge fitment and then some prototypes in plastic that didn't quite work out for various reasons.
Progress! Actually, *lots* of progress. I got the Speeduino off the carboard box it's been living on for just about the last year or so and stuffed into the stock ECU case. I need to make a new lid for it (since some of the components stick out the top), but it looks a lot less hokey already:
Emboldened by my success I wrapped up the adapter wiring harness I made:
Tuning has been going ... better than I expected it to. I honestly half expected I'd find a way to break it just trying to make it run, but it still seems happy. I'm 100% sure I'm leaving power on the table between not running the AVCS, running wasted spark/batch fuel and not wanting to push the timing too hard, but I'm tweaking one thing at a time. Idle AFR is now close to 14.5 or so. Low load cruise is into the high 13s but freeway cruise is still hovering around the mid 12s. An economy car it is not.
That's the negatives. The positive: This thing *moves* when you put the hammer down above about 4000RPM and it keeps moving right up past 7100. With the 3.9 final drive I can merge onto the freeway in 2nd at 7xxxRPM. 3rd gear tops out high enough to get me sent straight to jail in pretty much any state in the country.
In terms of next steps, I have some mundane stuff that needs to be attended to.
- The ECU needs to get tucked out of the way of the my passenger's feet to avert potential disaster. Long term I want to design and 3D print a new top for it with some room for the extra height of the board. Short term the whole thing (ECU, case and all) is probably going in a tupperware and getting shoved back under the carpet.
- I need to find out why the front right wheel wants to hop accelerating out of sharp turns and give me a bunch of steering wheel wobble when I hit bumpy sections of freeway
The next actually interesting thing to do will be to get some experienced help tuning timing so I can get a bit of the potential power in the lower rev range. I have a feeling my timing is really conservative right now, but I have no knock sensor. :S After that I need to hook an oscope up to the hall effect (?) cam sensors, figure out which trigger pattern they are and get them setup in the Speeduino so I can run sequential/non-wasted spark COP. That should help fueling a tiny bit, but mostly be less of a burden on my COPs, which are right now firing twice as many times per rev as they're designed to.