I've got an RS that has an STI harness,dash,column all ready in it, taht was running with a JDM motor, now has no motor or tranny, had a 5spd.

I also have ALL the suspension and drivetrain for an US STI, what problems will I have bolting everything in complete?

and getting hte center diff to workthe DCCD or whatever it's called.

I can't be the first one to do this, anyone know any members who have?

So you want to put a us sti drive line into an RS that was running a jdm STi motor?

well the JDM computer didn't seem to work too well in the car, things like the A/C, wipers, turn signals didn't work. the working theory is that with a US ECU it will work with teh us parts. I'm not worried about the motor running and such.

I guess what I need to knwo is will the the complete suspension and tranny (6 spd) bolt in (assuming i have all the parts from the STI) I believe people have put the 6 spd in gc8's but thats with teh motor in all ready.

basically if teh impreza had a steel frame, it would be like I unbolted the STI body off of the rolling chassis and dropped the RS body onto the STI chassis. since I believe the front crossmember bolts in then it's just a question of bolting in hte struts, right?

so does the rear crossmember bolt in? that way I can use the STI pumpkin, axles, yadda yadda.....

Stuff like the wipers/turn signals don't have a connection to the ECU. You probably have wiring issues elsewhere. AC does but that's likely a wiring issue. The JDM and US ECU are identical save for TGV/AVCS differences.

All the stuff on the bottom of the car should bolt in. The crossmembers are the same as far as bolt location. You'll widen the track of the RS a bit.

The strut tops on the RS aren't the same as the WRX/STI so you will need to find new strut tops to use with the suspension. You may also have some alignment issues in the rear but they can be taken care of.

The steering rack splines on the WRX/STI rack aren't the same as the RS. So you'd need to use your old steering rack or change around the u-joint.

Is your current motor a USDM STI or a JDM STI one? They are completely different as far as wiring goes. If the car was previously running a JDM motor, you need to either run a WRX or JDM STI motor, otherwise you are in for more work. The USDM STI has a completely different ECU from the WRX/JDM STI, it doesn't even have the same amount of plugs.

yup, what dwx said.

okay I didn't think they were gonna be any big issues for the suspension.


the deal is I'm buying this RS with no motor and tranny, I thought it had a JDM STI harness in it, but I think it has a US STI harness in it, but they were running a JDM STI motor that didn't run right with the JDM ecu. He is gonna swap his JDM motor into his WRX

well I've got the whole US STI harness and another front half of an US harness, but I was told that the Us STI was totally intergrated. that it was able to read more info from the car and that it had more control over things, I know an ECU can control the A/C are you sure that it can't defeat teh wipers and turn signals via the column?

I was also told that becasue teh harness is so integrated that the WHOLE harness has to to be transplanted, becasue if you were just to install teh engine harness you'd get all kinds of CELS (or whatever the STI has) for the brake lights nad all kinds of other things if you were to cut apart the harness

If the car has a JDM harness, can I just remove the pins from the JDM plugs and take the US STI connectors and re pin them?

okay I didn't think they were gonna be any big issues for the suspension.


the deal is I'm buying this RS with no motor and tranny, I thought it had a JDM STI harness in it, but I think it has a US STI harness in it, but they were running a JDM STI motor that didn't run right with the JDM ecu. He is gonna swap his JDM motor into his WRX

well I've got the whole US STI harness and another front half of an US harness, but I was told that the Us STI was totally intergrated. that it was able to read more info from the car and that it had more control over things, I know an ECU can control the A/C are you sure that it can't defeat teh wipers and turn signals via the column?

I was also told that becasue teh harness is so integrated that the WHOLE harness has to to be transplanted, becasue if you were just to install teh engine harness you'd get all kinds of CELS (or whatever the STI has) for the brake lights nad all kinds of other things if you were to cut apart the harness

If the car has a JDM harness, can I just remove the pins from the JDM plugs and take the US STI connectors and re pin them?

Dude, you are scaring me...
You need to find out exactly what version/year, etc. harness that is in the car and get a schematic for that harness and a schematic for the RS that it is in. Completely go thru the wiring and make sure everything is right. You need to get the motor that the harness is designed to run . OR- rip everything out and start over w/ harness and engine from a usdm car.
There is a reason this came to you in the condition that it is in-somebody bit off more than they could chew and sold it. I had the pleasure of repairing a swap-gone-wrong started by someone that had no idea what they were doing. I had over 100 hrs in the project before it was done and the mechanical was 80% complete when I got the car.
Get some more info and start from scratch. Good Luck and let me know if I can help.

_Rick
FIS

Yep, you need to find out EXACTLY what it is you have or what you are getting. The USDM STI uses the CAN protocol to talk to various things in the car, I guess it's possible for all of that stuff to be relayed via the ECU. I know with the USDM STI version of the Hydra standalone, you have to retain the stock ECU because other things on the car no longer function correctly.

Without knowing exactly what you have we are all wasting time, so I'm not really going to go into various scenarios on what could work with what.

Sounds like you are buying someones major F-up that they couldnt fix. Unless you are 100% confident in your abilities to fix this car you should run away fast. If it needs 100 hours of work at 75 bucks an hour well you get the idea.

Here are the facts / info on this:

It's my old car that a certain vendor on this site slaughtered. It has a JDM STi Ver 7 RA wiring harness (engine and internal) installed and hacked together to somewhat work with the stock parts from the RS and WRX dash conversion they did.

It has a JDSM STi steering column that has the turn signals on the opposite side as the USDM. The AC control panel is the JDM unit (Celcius) and the AC blower is a USDM unit.

We had the JDM Ver 8 RA motor installed in the car as well as the JDM ver 8 ECU.

The main problems were:
AC no work
ABS no work
Airbags no work


What bobturismo is asking is if a USDM 2.5 STi motor will bolt in and work with the JDM STi wiring harness that's currently in place, or if he has to start over.

Sounds like he needs to seek professional help(w/ the install, not his brain) and start over.

_Rick
FIS
Here are the facts / info on this:

It's my old car that a certain vendor on this site slaughtered. It has a JDM STi Ver 7 RA wiring harness (engine and internal) installed and hacked together to somewhat work with the stock parts from the RS and WRX dash conversion they did.

It has a JDSM STi steering column that has the turn signals on the opposite side as the USDM. The AC control panel is the JDM unit (Celcius) and the AC blower is a USDM unit.

We had the JDM Ver 8 RA motor installed in the car as well as the JDM ver 8 ECU.

The main problems were:
AC no work
ABS no work
Airbags no work


What bobturismo is asking is if a USDM 2.5 STi motor will bolt in and work with the JDM STi wiring harness that's currently in place, or if he has to start over.

The USDM STI motor will mostly work. Notice I said mostly. The two hurdles you'll run into are the throttle by wire and the fuel system. You can rectify that by using an entire intake manifold setup with throttle body from a WRX with the right sized injectors. Or just get the spacer part with the fuel system and the complete throttle body. The engine harness is different as well, you'd need to find a JDM or WRX engine harness.

Making that stuff work with what you currently have would be costly in terms of time and money. Definitely not worth it.

As for the non-working accessories and whatnot. If they put a JDM harness in the car, all the plugs for that stuff are on the wrong side of the car. Chances are they didn't extend those plugs, they are likely still hanging out somewhere under the dash. Either that or they just cut them off to save space. That's why it's about 100x harder to swap in a RHD harness than to just splice into the existing one. It's very possible the ABS and Airbag computers, which have no connection to the ECU, are not there.

My 2 cents are don't bother with a complete USDM STI engine, it's just not worth it, unless you are getting it for some insanely cheap price. Get the JDM STI engine or get a WRX engine. If you really want a 2.5L, buy an EJ257 block.

Dude the best way to go about this would be strip the car down to the ground and totaly start over.
My 2 cents are don't bother with a complete USDM STI engine

Ya, there realy isnt a reason to put yourself threw that work. If your ver 8 isnt enough for you then later you can get a 2.5 short block and re tune your ecu.

I've got all the parts I need to do teh COMPLETE conversion, I was jsut wondering if I could get away with not installing the harness, column and dash

can I get it running with just droppign the motor? and what do I need to do about the fuel and fly by wire problem (assuming I have all the parts off of an STI)?
I'll swap the US harness and dash later

I've got all the parts I need to do teh COMPLETE conversion, I was jsut wondering if I could get away with not installing the harness, column and dash

can I get it running with just droppign the motor? and what do I need to do about the fuel and fly by wire problem (assuming I have all the parts off of an STI)?
I'll swap the US harness and dash later
The harness on the US STi is different then the jdm one. It will not just plug in... and for the US motor and harness you may need the US STi peddle box. What you may beable to do is change the connectors on the US STi motor so it will plug into the jdm harness... but with out knowing what shape the harness in the car is in and so on it could just make things take even longer then stripping the car down and rewireing everything. Anyway you go about it using the wrx/jdm STi intake manifold and T. body, using a new harness, or rewiring the block its going to be a lot or work and take a very long time.

even the engine to harness plugs are different? that can't be taht would mean taht subaru would have to maek a differnet part for every sensor, becasue most of the sensors/switches/components don't have pigtails.

even the engine to harness plugs are different? that can't be taht would mean taht subaru would have to maek a differnet part for every sensor, becasue most of the sensors/switches/components don't have pigtails.
The harness is different... the ecu is different, there are different sensors. One will not plug in and work off the other harness. Heres a walk threw of what dwx said about using a wrx intake manifold. http://elementtuning.com/technical/ej25_install.htm