when you swap a motor like say a 05 sti motor into your rs, instead of rewiring the harness, why don't people just buy a 05 sti ecu? is that possible?
ecu question
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the ecu connectors won't fit, plus there is more than just the ecu that you will need from the sti. for example, the rs has a cable driven throttle and the sti's is electronic, you'd need a new setup for that as well. it makes it a lot less complicated if you just rewire the harness for the new engine
People do use a different ECU, in fact, you have to. An RS ECU only knows how to operate a RS engine and you need the right ECU for the right engine (this isn't purely true, but for a simple explanation, it is) The re-wiring part comes in making it work with all the other crap on your car that you can't convert.
N00b
Thanks for that helpful comment..
yes thank you for the helpfull and not so helpfull comment. But anyways, what would be an easier swap than a 05 sti motor? would the 05 wrx motor or is it still ran by computers?
with any turbo engine you're going to need the ecu for that engine.....when swapping there really is no way around ecu swap and harness merging
I dont know of any EJ series motors NOT run by computers.
maybe pre-93? I dont knwo what subaru did before the impreza, just never cared to research it.
Chris
no hahahah sorry, let me clarify, i meant if the 05 wrx still ran by electric or is it throttle cable?
oh and would the install be easier for me because if i'm not hooking up power windows, power mirrors, dome light,a/c,and air bags. are those the things you meant?
The best way to go with a swap is to do a harness merge. Regardless of what people say swaping the whole harness in is a PITA cause you still have to merge a bunch of wires for the lights, windows doors and other stuff. I've done both and the second method flat out sucks because you have to do lots of little merges throughout the harness rather then one big merge in one place.
Z
Z
ahhh i...c.... so the less you have(windows,pdl,windshield wipers,blahblahblah) it would be easier? correct?
Are you planning on doing this or are you just trying to learn? If you're going to do this, I'd really consider having a shop do it for you. There's a lot of confusing info in this thread, and I'm not sure you sound ready to tackle something like this on your own. However, if you're just learning, it's all good.
yea it would be a bit easier if you don't have that stuff, but not that much. those sort of items don't take much time at all to incorporate back into the harness. Actually, I think that people who merge (say for an example) an 05 wrx engine harness with a 99 rs harness merge only the wires that matter for the engine and supporting accessories contained in the engine bay. If it is done right, things like doors and windows that stuff should be untouched.
if i got the wording of your original question, a newer ecu can't plug into an older harness, not only would it not fit, but as other people said, there are other things missing and if for some reason you got it to work, you would have a lot of trouble on your hands.
There is also one other option, if you can source a wrecked car, you can use the entire harness from the WRX and put it in your older impreza and splice for a couple things, like the doors, front lights, tail lights, roof lights, and dash if you keep that.
if i got the wording of your original question, a newer ecu can't plug into an older harness, not only would it not fit, but as other people said, there are other things missing and if for some reason you got it to work, you would have a lot of trouble on your hands.
There is also one other option, if you can source a wrecked car, you can use the entire harness from the WRX and put it in your older impreza and splice for a couple things, like the doors, front lights, tail lights, roof lights, and dash if you keep that.
I plan on doing the swap in the future, so right now i'm just trying to get as much information that I can. thank you guys for your help.
Its actually the other way around. Most of the engine bay stuff remains intact since you would be using the 05 ECU, you splice in the necessary dash components, etc.
OP: Check out the stickies at the top of this forum and give them a good read, they will definitely help you out.
As a tool , I cannot speak
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