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Thread: From 2.5i/4EAT to 3.0/6MT: Building My Own 3.0R Spec B Wagon

  1. #1

    From 2.5i/4EAT to 3.0/6MT: Building My Own 3.0R Spec B Wagon

    I wish I had started documenting this before I was 3/4 of the way through the process, but I didn't. The title is self explanatory; it's not what I WANT to do. It's exactly what I'm doing. To add, everything I'm posting here is strictly from memory. I will forget to add something, so ask me questions and It'll probably jog my memory enough to answer it if I can. So lets begin.

    Driveline: What I'm using

    Engine: EZ30"R"
    Trans: TY856WVCAA (2006 Legacy 6MT Transmission)
    Driveshaft: No change. 6MT uses the same prop shaft
    Rear Diff: 3.54 "FM" Classification R160 (cheaper and easier to find, and a viscous LSD for what it's worth)
    Mounts: 5MT sourced Transmission crossmember, EZ30 specific engine subframe.

    Other Things:
    Engine Mounts
    A boatload of connectors from iWire
    Pedal box (any 5MT pedal box will work)
    Clutch master cylinder
    Master cylinder hard line and mounting bracket
    Slave cylinder flexible line
    Radiator
    Fan assemblies
    Heater core hoses
    Radiator hoses
    A/C High/Low pressure lines
    Intake
    Haltech Elite 2500 & WB2
    Front axles (The axles are the same but mine were roached)
    Rear axles (AT uses 22 spline input, MT uses 25 spline)
    STi 6MT short shift assembly (which you can buy here)
    USDM Spec B shifter surround
    Shifter boot
    Shifter mounting plate
    Shifter Stay bushing
    Headers
    Various Fasteners

    So what fits and what doesn't?

    Well, since this is a 4EAT shell, everything fits without modification. All of the mounting points for the manual transmission cross member, pedal box, and master cylinder are present. 5EAT cars will need some work but that's a discussion for someone that isn't me. Otherwise, the process is as simple as dropping the old engine/transmission out and swapping the new one in. Highly recommend mounting the shifter before mounting the rear of the transmission. There's not a lot of room in the tunnel once everything is in place.


    Where it gets complicated is when you start wiring everything up. There are some commonalities between a 4 cylinder and 6 cylinder harness but they are few and far between. There are further differences between AT and MT harnesses. Most of them can be worked around if you're savvy enough but I'd wager for most people, it would be easier to just find a H6 Outback or Legacy donor and swap the bulkhead harnesses completely. I didn't do that because they're rare as hen's teeth in the southeast and I don't have the space to keep them both if I could find one. This, combined with the ease of tuning, is why I opted to run an Elite 2500. The way I've opted to approach this is by using a flying lead harness from Haltech, building an engine harness to run from the ECU to the engine receptacles, and merging other functions where needed.

    So far the only major difference I've found electrically is the fan circuit. Fans on the H6 cars are controlled directly by the ECU through the PWM mounted to the sub fan shroud. I thought I could work around this by retaining the H4 fan assemblies in some capacity but it isn't physically possible. The solution, then, was to adapt the H6 fans to the H4 harness by cutting the pigtails off of the H4 fans and soldering them to the H6 fans. Since the Elite has multiple Stepper/DPOs, I was able to assign two DPOs to control the main and sub fan relays. It uses coolant temp values to trigger those outputs, so to test them, I set the "on" temperature a couple of degrees higher than what the coolant temp sensor was reading and hit the key. Worked a treat!

    There are differences between the injectors and ignition systems between the two cars (obviously) but they receive power at the same points on the main engine harness, so the simple solution was to de-pin the ignition and injector power wires and place them in the new engine connector. Just run a ground wire for the ignition coils, since they are normally grounded to the ECU. The rest is controlled by the Elite. EZPZ.

    The starter circuit is identical outside of the way it's controlled. The manual uses a clutch pedal switch where the automatic has an interrupt switch on the shifter assembly that breaks the ignition relay circuit when not in P or N. The latter is not used since the starter relay is controlled by the Elite using a switched ground DPO. The relay runs power through the clutch pedal switch and out to the Elite by setting the DPO to switch to ground when activated. Activation is controlled by a generic sensor ("GenSens") that is looking for 12V. This is wired to the start position on the key. As a secondary condition, the Elite also looks for engine RPM to be below 350. If those two conditions are met, then the elite switches the DPO to ground and the starter relay closes.

    More to come. Here are some pictures from along the way.
    Attached Images Attached Images      

  2. #2
    SLi Resident Tylerhartman's Avatar
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    excited to see more of this, this is gonna be good
    1999 Legacy GT Wagon 5SPD (Stella)" Race Wagon"
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    UPDATE TIME!

    It's been a minute since the first post and much has changed since then. I've been busy chipping away at it but with everything at work and school, progress has been slow.

    The haltech now has 95% of its connections made with A/C request and a couple of other nonessential items left undone for the time being. I've had to go back and tackle some wiring gremlins that I had inadvertently created for myself. Most of it was not fully understanding how everything is supposed to work, but nothing ever amounted to being dangerous to the engine or the ECU. Just a lack of functions.

    For starters, I ran into an issue with the DBW motor that wouldn't calibrate which was accompanied by a P2109 engine code. TL;DR: My brain is the size and texture of a peanut and I didn't have the power wire hooked up. Once that was resolved, I made a couple of attempts to crank the engine over to verify trigger and home inputs as well as base timing. Verifying base timing took a little bit of creativity, involving a distributor coil lead and a timing light connected to the cylinder 1 ignition coil, but I made it work. The crank signals were coming back ok, but the cam position sensor seemed to be throwing a home reference error, which I attributed to noise on the signal ground. Again, lack of understanding on my part. Since subaru used the same signal ground for nearly every powered sensor on the engine, I assumed I could do the same. I assumed incorrectly. I figured it would be best to isolate the cam postion sensor altogether, so I made a breakout harness to separate all of the signals related to the cam position sensors from any other circuitry on the engine. It worked, but I would later discover that it would need some further modification. More on that in a bit.

    With everything seemingly verified, I felt confident that I was ready to attempt to start the car. I turned the key, and the engine fired....then died. But it did start, so that was a win as far as I was concerned. The only problem was it wouldn't stay running. I didn't know what to think at this point, so I put it down for a bit, mulled it over, and decided to bring the car home from my friend's shop. Before I had it brought home, I had it brought to an exhaust shop to have a mid-pipe made to connect the headers to the catback, just so I could say it was done. I plan to go back and put cats in it later, but for now I wanted to make sure that was done so I could work on the car and attempt to start it without my neighbors hating me (more).

    That weekend, I spent hours pouring over HP Academy's videos on standalone tuning, preparing myself to have to start from zero. Sunday afternoon, and I'm through to a point I felt I needed to hit to at least get it running and make sure everything is working as intended. But before I go fully off the deep end, let's try the haltech map one more time...

    SUCCESS!!! The car roared to life with the most beautiful 6 cylinder symphony I've heard in a long time! I had a suspicion that the reason the car wouldn't start at the shop was because the oxygen sensors were reading "free air" constantly, but I didn't have a way to prove it. It turns out I was dead on the money with that assumption, because as soon as the test pipe was connected and they had an exhaust stream to read, it came to life! On to making sure everything works when it's at temp and that I don't have any gushing leaks.

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    Aside from a radiator hose clamp that wasn't fully tightened down, there were no leaks to speak of! This is going swimmingly! Bled the cooling system, verified the thermostat was working and all was well, though I had wired my primary cooling fan in reverse. No biggie. Just de-pin the wires and move them to the opposite side.

    With the cooling fan sorted and the cooling system bled, it was time to try to make it move around. While it will run and drive, it' seems to stumble and fall off above 20% throttle. My initial thought was there was something throwing the fuel load off a bit, so I started checking inputs on the ESP software. I found that my AVCS and AVLS weren't working. A few minutes of digging on Haltech's support page and I quickly discovered why. The Elite uses a synchronised pulse input (SPI) to tell the software where the camshafts are relative to the home position. Based on that input data, it commands the oil flow control solenoid to open or close however much to adjust the cam phaser by switching to ground. When it works, the ESP can show you a target and actual angle on both (or all if you have more) cam phasers. Mine were displaying "uncalibrated" because I had misinterpreted the wiring assignments and the factory service manual to a point where the ECU would've been commanding ground for an unpowered circuit and had the signal wires looking for signal where there was none. That was a big ol' OOF on my part. This is where those further modifications to the cam position sensor breakout harness come into play. Now, the home wire supplies power and ground to both cam position sensors, and one of them has the signal+ wire running back in parallel to the home wire and to one of the SPIs for cam angle control while the other simply sends signal back for the other cam angle control. I repurposed the car's original oxygen sensor power wire to power the AVCS and AVLS solenoids, which the Elite controls by switching ground. That leads us to today.

    After fixing my self inflicted AVCS/AVLS issues, I think I have addressed everything in terms of engine control, but it still has that same hesitation above 20% throttle at lower engine speeds. I can nurse it past the initial hesitation, but I'm still only acheiving about 25-30% throttle before it comes back. It's fuel related, but I'm not sure if the engine is running out of fuel or if it's cutting fuel. I have a sneaking suspicion this is also my fault, but I'm out of time to test it. In the meantime, I think I'm gonna eyeball that AEM fuel pump a little harder now...

    More to come.

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