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Old 08-22-2017, 11:52 AM   #1
Scooby Specialist
Member#: 115107
Join Date: May 2006
Chapter/Region: NESIC
Location: Waitsfield VT
02 wrx wagon
61 Morris Mini

Default 2008 Sti donor, 2002 wrx hillclimb car

Long story short, I have an 02 WRX hillclimb car. I managed to get 180,000 miles out of it's ej205 before spinning a bearing. Unfortunately, it happened on my first run up Mt Washington.
I've also been running 5 speed boxes, which I've hoped to upgrade to a 6 speed for quite a while.
In searching for a motor replacement, I came across a fantastic deal on a side hit 2008 STI hatch with less than 28,000 miles on it. So I ended up with a full car for less than I could find a six speed swap.

I am pretty well set on the mechanical side of the conversion, that info is well established. There might be a few gotchas in there, but pretty minor.

For me, the wiring side of things is the most intimidating side, and I'm hoping for some guidance.
As I see it, there are a few directions that I can go.

1-keep the 02 ecu, covert the engine to drive by cable, disable AVCS. Potentially lose the full power potential of the car.

2-Go with an aftermarket ECU and custom wiring harness. Most expensive option I think, though I do have an old Motec that might work. The downside is that an aftermarket ecu causes some issues with classification rules.

3-Go with the 08 ecu and near 100% of the wiring. Basically, merge lights, wiper, locks, windows and weld in a dbw throttle. Unsure about the fuel pump side of things.

3 is where I'm leaning towards, but I find I have plenty of questions. Being a CAN type of setup, I know even less about the setup. I've read a bit here, but don't feel confident about the plan just yet.

So this is a race car, but competes in a street prepared category, in theory, it should function as a normal street car, and be quasi street legal(no air bags, 5 point harness instead of oem belts). So aside from safety related stuff, it needs to street legal ish. It does not need to pass a state vehicle inspection.

I have the full car at my disposal. I'm hoping to use the 08 dash setup in the car. Research indicates that it will work, but there might be some weird gaps in places. I'm ok with that.
I don't really need(want) any of the ABS brake stuff.
I know the 08 trans presents some issues, does the dccdpro VSS module solve all of that? I plan to run the hubs from my 02. I seem to recall reading that the 08's like to see all the wheel speed sensors.

I don't need the ABS to work and prefer it doesn't. I don't need the VDC to work nor want it to work.

So....what are the challenges I need to address? I have two complete cars at my disposal, plenty of garage space and a thoroughly tolerant wife.

Thank you
PS, if you need some cosmetic stuff from an 08 sti, send me a PM.
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Old 09-13-2019, 12:11 PM   #2
Scooby Specialist
Member#: 115107
Join Date: May 2006
Chapter/Region: NESIC
Location: Waitsfield VT
02 wrx wagon
61 Morris Mini


a bit of a zombie thread, but I do have an update a few years later.

Long story short, it took about year before I actually had the 2008 sti in my possession and could accomplish the physical part of the swap. Had Iwire do the wiring and their canbus emulator.
Much to my pleasure, aside from forgetting about the differences in the fuel pressure regulator between and 02 vs 08 style motor, the motor swapped functioned out of the box.
Went to tune and we found the AVCS would not activate from it's self test. Basically it needed to see 0 mph on the self test to activate, and for some reason there was noise while sitting still that was sending random mph numbers to the ecu other than 0. With a non avcs motor it wouldn't have been an issue. Thankfully my friends at VEMS tuning are pretty resourceful guys and over time were able to figure and conquer the issue.
I'll update more when time permits on the process and challenges.
Right now as it sits
02 sedan chassis, hillclimb race car.
2008 STI hatch donor(side hit). Used the engine, transmission, rear diff, ECU, instrument cluster, si drive switch, integrated body unit(I think thats what its called) Iwire harness.
For now the engine is stock with just an air intake, turbo back exhaust, and fuel pump, vems coolant balance kit. I do have a bunch of other stuff, but for now wanted to make sure all is working before I add new variables into the equation. First driving event for this setup is this next weekend(ascutney hillclimb).
If you can see facebook videos, the dyno runs are below
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