Subaru Legacy NA to full Turbo swap build thread
Posted: Fri Jun 04, 2021 6:46 pmHi all, after having some problems lately, members of the facebook group pressured me into wirting a build thread for better analyzing the problems and for storing the answers..So here we go 
I'm from Germany, and the highest hp model we got was the 3.0. After watching the Supergramps build years ago, I decided to buy myself a Legacy Wagon as my first car (at that time I was 17 years old). I Really liked the looks, the AWD, the boxer rumble, just an awesome car overall. Over the years normal mods like springs, new brakes, the usual stuff happend.
After I finished school, I worked for an exhaust company for 1 year, to bridge the time until apprenticeship would start. That's when I met my coworker, and the downward spiral began
He had an 05 STi sitting in his front yard he had crashed and flipped it like 7-8 times (got lucky that he survived without injuries), but he wasn't ready to let it go. We always made fun of how awesome it would be to have a turbo legacy, as he was into the mk4 legacy aswell. Side fact: Last year he got himself a full spec 06 facelift legacy with the 2.0 turbo and 6MT, really nice car.
Long Story short: I quit the job to start apprenticeship, and 1 year later he calls me and says 'Either you take it for free and part it out or I'm gonna tow it to the wreckers'. So I got myself a trailer and brought it home.
I ripped it all apart, and started looking on what could be used on the legacy and what was junk. In the end, I only used the 6MT, the exhaust manifold + turbo and the brembos for the legacy, either selling the other parts or throwing them away.
Because of german TÜV, I could only use OEM parts to have any chance of getting it engineered afterwards (still not done).
To the build list:
- ej207 wc20 shortblock (bought of subaru with crank, rods and pistons)
- ej20x/y heads, fully machined
- inconel intake and exhaust valves
- arp head studs
- rcm head gasket
- jdm lgt intake manifold
- jdm lgt tgv deletes
- jdm lgt fuel rail system
- group n engine mounts
- group n trans mounts
- full PU bushings on everything
- the r180 special diff bracket thing
- frankenstein r180 rear axles with lgt and sti parts
- genuine oem r180 ltbsti backing plates for the brembos
- lightend flywheel and stronger clutch
- kartboy shortshifter
- lgt auto ecu
The ecu thing is spaced out on purpose. I completely focused the turbo yoda in myself and cut up the wiring harness in the passenger footwell. Bought the matching rhd wiring harness of a jdm lgt, removed everything non engine, and spliced it into my n/a loom. Was a heck of a job, but finally, the engine started and is now working. The car is currently working, but that's about it. I got 3 remaining problems:
- Somehow my throttle is not working correctly, it picks up the throttle, but it limits it. I have a tactrix cable, but no clue on how to access the ecu. When the car was at the shop to get the key programmed, we could see that the throttle plate sensor does work correctly (it knows how much % its open when pushed by hand), but I could't check if its the servo inside thats shot or what's going on. As I said it's running on a auto ecu, we grounded it so it knows its manual, but could be still because of auto.
- I still get a 'Er HC' in the dash, not quit sure why because the key is programmed in, but that's for another time.
- The last big one is that my AC does not work, I did not change anything in the wiring, I checked all the fuses, but the control panel does not work. I got 2 and none work, I tried switching the HVAC ECU but idn't help either. As I understand if you have an AC it's relevant for getting your TÜV...
I hope that summarizes the build for future problems, like I said that throttle problem is annoying af...
Greetings from germany, keep it up guys
I'm from Germany, and the highest hp model we got was the 3.0. After watching the Supergramps build years ago, I decided to buy myself a Legacy Wagon as my first car (at that time I was 17 years old). I Really liked the looks, the AWD, the boxer rumble, just an awesome car overall. Over the years normal mods like springs, new brakes, the usual stuff happend.
After I finished school, I worked for an exhaust company for 1 year, to bridge the time until apprenticeship would start. That's when I met my coworker, and the downward spiral began
He had an 05 STi sitting in his front yard he had crashed and flipped it like 7-8 times (got lucky that he survived without injuries), but he wasn't ready to let it go. We always made fun of how awesome it would be to have a turbo legacy, as he was into the mk4 legacy aswell. Side fact: Last year he got himself a full spec 06 facelift legacy with the 2.0 turbo and 6MT, really nice car.
Long Story short: I quit the job to start apprenticeship, and 1 year later he calls me and says 'Either you take it for free and part it out or I'm gonna tow it to the wreckers'. So I got myself a trailer and brought it home.
I ripped it all apart, and started looking on what could be used on the legacy and what was junk. In the end, I only used the 6MT, the exhaust manifold + turbo and the brembos for the legacy, either selling the other parts or throwing them away.
Because of german TÜV, I could only use OEM parts to have any chance of getting it engineered afterwards (still not done).
To the build list:
- ej207 wc20 shortblock (bought of subaru with crank, rods and pistons)
- ej20x/y heads, fully machined
- inconel intake and exhaust valves
- arp head studs
- rcm head gasket
- jdm lgt intake manifold
- jdm lgt tgv deletes
- jdm lgt fuel rail system
- group n engine mounts
- group n trans mounts
- full PU bushings on everything
- the r180 special diff bracket thing
- frankenstein r180 rear axles with lgt and sti parts
- genuine oem r180 ltbsti backing plates for the brembos
- lightend flywheel and stronger clutch
- kartboy shortshifter
- lgt auto ecu
The ecu thing is spaced out on purpose. I completely focused the turbo yoda in myself and cut up the wiring harness in the passenger footwell. Bought the matching rhd wiring harness of a jdm lgt, removed everything non engine, and spliced it into my n/a loom. Was a heck of a job, but finally, the engine started and is now working. The car is currently working, but that's about it. I got 3 remaining problems:
- Somehow my throttle is not working correctly, it picks up the throttle, but it limits it. I have a tactrix cable, but no clue on how to access the ecu. When the car was at the shop to get the key programmed, we could see that the throttle plate sensor does work correctly (it knows how much % its open when pushed by hand), but I could't check if its the servo inside thats shot or what's going on. As I said it's running on a auto ecu, we grounded it so it knows its manual, but could be still because of auto.
- I still get a 'Er HC' in the dash, not quit sure why because the key is programmed in, but that's for another time.
- The last big one is that my AC does not work, I did not change anything in the wiring, I checked all the fuses, but the control panel does not work. I got 2 and none work, I tried switching the HVAC ECU but idn't help either. As I understand if you have an AC it's relevant for getting your TÜV...
I hope that summarizes the build for future problems, like I said that throttle problem is annoying af...
Greetings from germany, keep it up guys
