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Old 04-23-2015, 01:54 PM   #1
FrigganSpriggan
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Question 2015 WRX CVT Transmission Swap to 2015 STI transmission

I bought my 2015 CVT with the eventual goal of swapping in an STI transmission. The time has come for me to start gathering the parts for this build project. I know where I can purchase a used/salvaged STI tranny from, but I am not really sure what else I will need to perform the swap. Are there any SuGurus out there that may be able to shine some light on what else might be needed to perform this swap successfully? or that can point me to some resources where I can see the difference between the drivetrains? google has been less than fruitful on the subject. Thank you for any assistance you can give.

I guess what I am really looking for are breakdowns/ schematics / blueprints / etc of both cars... so if you know where this information is, please link me and I will do all the research I need to. Not looking to be told how to do something that has never been done before, just need assistance finding the material.
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Last edited by FrigganSpriggan; 04-23-2015 at 02:10 PM.
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Old 04-23-2015, 04:57 PM   #2
rkramer
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Quote:
Originally Posted by FrigganSpriggan View Post
I bought my 2015 CVT with the eventual goal of swapping in an STI transmission. [...] Not looking to be told how to do something that has never been done before, just need assistance finding the material.

WHY???? You are going to be spending far more than if you had bought the STi to start with. Not saying it can't be done, just curious as to the thought process behind that. Anyway, the mechanical aspects might be the least of your concerns. Once you get everything duct taped together, if the ECU isn't happy with its missing CVT, all the mechanical work is worthless.
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Old 04-23-2015, 04:59 PM   #3
FrigganSpriggan
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Because I want fa20 and twin scroll turbo... don't want anything stI except tranny
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Old 04-23-2015, 06:12 PM   #4
tibug
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You absolutely need the factory service manuals and I'm guessing the electrical work would make this extremely difficult and cost prohibitive.

Good luck with this...
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Old 04-23-2015, 06:14 PM   #5
FrigganSpriggan
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Ok nvm... I found another solution. Thanks mates!
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Old 05-05-2015, 02:57 PM   #6
SlideTru
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was it to trade to a STi, seriously? Im in a similar boat, and would have spent up to half the price diff of a wrx to sti just to get the sti box/rear diff in a wrx....o well. i bet it would be close pricewise to go to a sti box w/ allll the hardware compared to a replacement cvt if the thing failed and was not able to be rebuilt, if downtime wasnt an issue

getting a used sti 6spd would help this swap make more sense finacially(another question is does a 2014 or older mount the same as the 15), but as was mentioned the sti's tcu may or may not play well with the cvt-ecu. I could image you might need to go to a wrx 6mt ecu, but maybe not...someone will find out.

Before a trans and its mounts, there are the basics from the 6mt wrx to get (at least): brake pedal assembly, clutch pedal assembly, clutch master/slave cylinder, clutch lines. thats just a start

then the sti console for the dccd. Another question is will the wrx's tach display the sti's diff readout when a sti tcu is installed--man. Now that we went there, can you get the cvt's SI drive wheel controls to work?

I would wonder about the front corssmember on the cvt vs 6mt, thats an area to research. Be it that the sti has lsd in the front, i would want a factory sti rear diff or better. There is so much more to it, and it already sounds expensive....but is it cvt replacement expensive??
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Old 05-06-2015, 10:16 PM   #7
FrigganSpriggan
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Quote:
Originally Posted by SlideTru View Post
was it to trade to a STi, seriously? Im in a similar boat, and would have spent up to half the price diff of a wrx to sti just to get the sti box/rear diff in a wrx....o well. i bet it would be close pricewise to go to a sti box w/ allll the hardware compared to a replacement cvt if the thing failed and was not able to be rebuilt, if downtime wasnt an issue

getting a used sti 6spd would help this swap make more sense finacially(another question is does a 2014 or older mount the same as the 15), but as was mentioned the sti's tcu may or may not play well with the cvt-ecu. I could image you might need to go to a wrx 6mt ecu, but maybe not...someone will find out.

Before a trans and its mounts, there are the basics from the 6mt wrx to get (at least): brake pedal assembly, clutch pedal assembly, clutch master/slave cylinder, clutch lines. thats just a start

then the sti console for the dccd. Another question is will the wrx's tach display the sti's diff readout when a sti tcu is installed--man. Now that we went there, can you get the cvt's SI drive wheel controls to work?

I would wonder about the front corssmember on the cvt vs 6mt, thats an area to research. Be it that the sti has lsd in the front, i would want a factory sti rear diff or better. There is so much more to it, and it already sounds expensive....but is it cvt replacement expensive??
I just went with a 2015 WRX Base 6 speed MT actually. Basically everything you mentioned I had pondered myself and it was getting way too expensive far to quickly. I figure I will get an STI if/when they bring the EJ207 stateside or bring the hatch back to get that epic transmission. For now I'm happy with the WRX tranny, and when the gears need a rebuild I'll get a custom box with dog bone gears to satisfy my taste for adventure. Good luck with what you decide to do, I really don't have much more info on the subject unfortunately. Worst case can always buy a used STI down the road and just do an engine swap... I think that is the cheapest way to go about getting that tranny with aby thing other than the EJ25. Good luck mate!
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Old 05-07-2015, 03:24 AM   #8
Uncle Scotty
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oh the failboat....OH THE FAIL BOAT
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Old 05-07-2015, 04:48 PM   #9
IHaveAYaris
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wow

wat
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