4th Gen OBW CVT To 5th Gen Legacy GT Swap

[SubaruSquirrel]

Hey all!

I've got a crazy idea... I have an '11 OBW 2.5i CVT that I want to convert to a "GT" using parts from a 5th gen Legacy GT, as the title says...
If I can't find a parts car, which so far no luck on finding a scrapped LGT, then I would use a JDM EJ255 (this is the motor that fits the BR/BM chassis) and then it shouldn't be too hard to find the 6spd manual, driveshaft and rear diff. I need the USDM LGT ECU and body control module (also called integrated module I believe) and dash harness to match. Most of the stuff between my OBW and the LGT are the same... Gauge cluster, stereo, climate control, etc. I looked up the LGT ECU and Body Control Module at my local dealership and price-wise it isn't too steep. Probably spend about $1k on the harness, ECU and BCM to get it new. I'm hoping that with using my VXDiag module and SSM3 or SSM4 that I can set the VIN to match my body... Not sure about this. Any thoughts on what else I might need programmed to match up? Will I need the anti-theft module from an LGT?

Does anyone here have the knowledge about these parts to help me figure this out and what I will need all to do a full proper conversion? Obviously I'll need to change the fuel pump, as well... I can't think of anything else that I would need other than ECU/BCM, harness, fuel pump, engine/trans & rear diff bc it is a different ratio from the CVT rear diff. I'll also need to do the manual swap, so clutch master cylinder, pedal & brake pedal from the manual. I did some looking around on the firewall to see where the master cylinder would go... That is kinda my bigger obstacle I think since the rest of the goodies should plug and play once installed. I need to see some pics of the clutch pedal/cylinder setup on a manual OBW or Legacy 2.5i.

You might be asking why I don't just find an LGT to buy and get rid of my OBW or something, but my OBW is in great condition body/interior and well maintained mechanically & 5th gen LGT's are not easy/cheap to find. I already have STi calipers front/rear, upgraded front/rear swaybars/endlinks, 2.5" AFE catback and I enjoy having a little more ground clearance than with a sedan. Eventually I would get wider rims and stiffer springs and probably do some chassis stiffening in the front and rear with strut tower bars and whatnot... Also aiming for 300AWHP, which isn't an insane target at all... I'd be very happy with all of that. We just picked up a '24 OBW Touring XT, so now this older OBW is my project car to have fun with.

Thanks in advance!

[Falcor]

Dumb question, would it be an option to go with the 3.6 and 5 speed auto? Those should be way easier to find. No manual, but parts should bolt right up. 

[SubaruSquirrel]

1 hour ago, Falcor said:

Dumb question, would it be an option to go with the 3.6 and 5 speed auto? Those should be way easier to find. No manual, but parts should bolt right up. 

Yea, it would be easier to source parts and I have considered it. Still, I could buy a 3.6 4th gen. I'd prefer to go with the ej255 & 6spd swap. Just need the usdm ecu & other electronics/harnesses. 

[silverton]

I don't think anyone has done this. You will have to pave the way. I think you're going to spend thousands and thousands of dollars just to find it can't work, just due to the fact that a legacy and an outback are kind of the same, but different enough. Oh, and not all EJ255's are the same, you would need one with the two piece oil pan.

You're far better off finding a 3.6 donor, and putting a 6 speed behind that. 3.6's make more power (1hp less than an STi stock for stock), and you can put a supercharger on them if you want more.

Edited February 21 by silverton

[Falcor]

It’s not apples to apples, but Subaru did something similar with a 2009 SEMA build (Legacy GTk). I contacted the shop who built it (If I remember correctly) trying to get info on it. They might be helpful. I’ll see if I can find that contact info.

[SubaruSquirrel]

9 hours ago, silverton said:

I don't think anyone has done this. You will have to pave the way. I think you're going to spend thousands and thousands of dollars just to find it can't work, just due to the fact that a legacy and an outback are kind of the same, but different enough. Oh, and not all EJ255's are the same, you would need one with the two piece oil pan.

You're far better off finding a 3.6 donor, and putting a 6 speed behind that. 3.6's make more power (1hp less than an STi stock for stock), and you can put a supercharger on them if you want more.

I hear ya, but was the 3.6 offered with a manual trans in the obw or legacy?

[creep_nu]

japan had the wagon variant that had the 2.5t and 5 speed slush box...if i was a gambling man it's the same tranny as the 3.6...so there is precedence for all of this working together, it's just gonna take a lot of piecemealing and working stuff out.  better off to buy a wrecked GT off copart (last time i looked there were 4?) and doing a whole swap with everything

[SubaruSquirrel]

2 hours ago, creep_nu said:

japan had the wagon variant that had the 2.5t and 5 speed slush box...if i was a gambling man it's the same tranny as the 3.6...so there is precedence for all of this working together, it's just gonna take a lot of piecemealing and working stuff out.  better off to buy a wrecked GT off copart (last time i looked there were 4?) and doing a whole swap with everything

That is what I'd like to do. I'll look on copart.

[dgoodhue]

A 3.6R is not less than 1hp lower than a typical STI. A 3.6R manual was never made by Subaru only the 3.0 motor 6MT  in the prior gen in non us markets.  

The JDM motor has different compression ratio than the USDM motor.   If you want it to actually run right, you need to swap the pistons or spend money for a custom tune or aftermarket ECM. The JDM motor may not be complete either. Your best bet is finding a donor but as I am sure you’re experiencing is they are rare and hard to find. 

[SubaruSquirrel]

18 minutes ago, dgoodhue said:

A 3.6R is not less than 1hp lower than a typical STI. A 3.6R manual was never made by Subaru only the 3.0 motor 6MT  in the prior gen in non us markets.  

The JDM motor has different compression ratio than the USDM motor.   If you want it to actually run right, you need to swap the pistons or spend money for a custom tune or aftermarket ECM. The JDM motor may not be complete either. Your best bet is finding a donor but as I am sure you’re experiencing is they are rare and hard to find. 

Yea, they're not easy to find. I'm determined, though. If I can get a whole wrecked car that would be the best. I did that once before years and years ago when I was into Toyota's and picked up a wrecked '91 Celica All-track... AWD Turbo 2L engine and I swapped that motor into a '94 Celica bugeye body along with a manual trans from a V6 Solara and a VLSD from an MR2. She ripped and was a ton of fun. I had to make a hybrid engine harness, but I got it all done myself and preserved all of the original features. Now-a-days with all the CANBUS bullshit it's obviously way more involved. I do have a place to park the wrecked car and do the work, so if I can get the donor car for the right price I'll be set.

[dgoodhue]

49 minutes ago, SubaruSquirrel said:

Yea, they're not easy to find. I'm determined, though. If I can get a whole wrecked car that would be the best. I did that once before years and years ago when I was into Toyota's and picked up a wrecked '91 Celica All-track... AWD Turbo 2L engine and I swapped that motor into a '94 Celica bugeye body along with a manual trans from a V6 Solara and a VLSD from an MR2. She ripped and was a ton of fun. I had to make a hybrid engine harness, but I got it all done myself and preserved all of the original features. Now-a-days with all the CANBUS bullshit it's obviously way more involved. I do have a place to park the wrecked car and do the work, so if I can get the donor car for the right price I'll be set.

I know how rare the Celica All-Trac are. They have similar total production numbers as the 5th Gen GT has. You can also look a GT with Burnt Valve. I have bought two and I have seen other GT for sale with them as well.   

[creep_nu]

@SubaruSquirrel NVAKeith posted this up...if you wanna do a GT transformation there's a chassis for ya..

 

[SubaruSquirrel]

2 hours ago, creep_nu said:

@SubaruSquirrel NVAKeith posted this up...if you wanna do a GT transformation there's a chassis for ya..

 

Thanks for letting me know. I don't really want to pay that, plus shipping and then have to repair the motor, too. I'm keeping my eye on 2 wrecked GT's on Copart. Waiting for the auctions to start. 

Edited February 23 by SubaruSquirrel

[creep_nu]

sweet.  good luck!  i always thought if something were to happen to my GT i'd go down the wagon route and swap everything over to an outback shell, hope you get this done, i'd love to see it.

[Scubaboo]

Document it if you go through it please!

Electronics will be the big hurdle and I think an LGT parts car should ensure you have everything you need to pull it off.

[SubaruSquirrel]

I will definitely document it. It's not only electronics, but since I'm doing an AT to MT swap I'll need a bunch of parts for the clutch pedal/master cylinder, too. I plan on getting a donor LGT. I want the LGT hood, too. It'll bolt right up to my OBW. I plan to use the TMIC to start out and then eventually I'll go to an FMIC.

[Scubaboo]

1 hour ago, SubaruSquirrel said:

I will definitely document it. It's not only electronics, but since I'm doing an AT to MT swap I'll need a bunch of parts for the clutch pedal/master cylinder, too. I plan on getting a donor LGT. I want the LGT hood, too. It'll bolt right up to my OBW. I plan to use the TMIC to start out and then eventually I'll go to an FMIC.

Oh yes, definitely a lot of work for sure!  But I am pretty confident all the relevant hardware will drop in, you have what is basically a Legacy wagon to start with already.

Very interested in your project because was thinking of something similar.  Am wanting a manual turbo car that is fun but can fit my family too.  Was thinking of selling my 5EAT Legacy, but was thinking about converting it to manual since I have a lot of time, effort, and parts in it.

I was researching Subaru auto to manual conversions and the conversion harness makers advise it can get complicated with the canbus cars.  

It was just an idea in my head, never really went into it but if you can pull it off you may inspire me to do it too lol!

 

 

[SubaruSquirrel]

10 hours ago, Scubaboo said:

Oh yes, definitely a lot of work for sure!  But I am pretty confident all the relevant hardware will drop in, you have what is basically a Legacy wagon to start with already.

Very interested in your project because was thinking of something similar.  Am wanting a manual turbo car that is fun but can fit my family too.  Was thinking of selling my 5EAT Legacy, but was thinking about converting it to manual since I have a lot of time, effort, and parts in it.

I was researching Subaru auto to manual conversions and the conversion harness makers advise it can get complicated with the canbus cars.  

It was just an idea in my head, never really went into it but if you can pull it off you may inspire me to do it too lol!

 

 

I shouldn't have any problems since I'll have a donor car and will be swapping wiring harnesses and all over to mine. I mean, you could do that to anything you want. I could build a tube frame kart chassis and put my current outback engine/trans into that and it would work. The computers don't have a clue what the chassis is, nor do they care. 

[Scubaboo]

9 hours ago, SubaruSquirrel said:

I shouldn't have any problems since I'll have a donor car and will be swapping wiring harnesses and all over to mine. I mean, you could do that to anything you want. I could build a tube frame kart chassis and put my current outback engine/trans into that and it would work. The computers don't have a clue what the chassis is, nor do they care. 

Yeah, should be straightforward if swapping everything over like that.  

[silverton]

Neat he turned it into a business.  the first exotruck is pretty sweet.

https://exotruckllc.godaddysites.com/

 

[Scubaboo]

1 hour ago, silverton said:

Neat he turned it into a business.  the first exotruck is pretty sweet.

https://exotruckllc.godaddysites.com/

 

Sweet!

[NVAKeith]

SS, do you live somewhere requiring emissions inspections?  I do. Curious if the state emissions OBD2 scan would be successful after putting the Outback VIN in the LGT ECU.  I’d probably start with a same year 6MT OB as they lack the PZEV rating as does the LGT. 

[SubaruSquirrel]

10 hours ago, NVAKeith said:

SS, do you live somewhere requiring emissions inspections?  I do. Curious if the state emissions OBD2 scan would be successful after putting the Outback VIN in the LGT ECU.  I’d probably start with a same year 6MT OB as they lack the PZEV rating as does the LGT. 

I live in PA and we have a yearly emissions inspection here. Not really concerned with this. I could check with the garage I take it to for inspection and ask them what they think, though. If I can leave the VIN unchanged from the ecu I will. If I need to change the VIN to match my body then I think I can do that with SSM3... If not I can probably get a local dealer to do it. The shop I take it to now never gives me any shit and I've had the EGR system removed and blocked off for like 2yrs now. I used romraider to disable the codes and whatnot. I know an independent mechanic, as well. He used to do my inspections and charged more, but it was basically a slap and stick job. He knows I maintain my vehicles. I figured since I don't have anything that is an inspection issue going on I might as well go to the big name local chain and have them do it for half the price and so for the past 2yrs I've been doing that. Btw, I got into an accident like 2yrs back and now she's an R-title car. We had already owned it for like 5yrs and paid off the loan and I was paid out like nearly $6k from insurance and spent like $4300-ish having it fixed up. It was a fairly minor accident, but it did tweak the front by 3/4". It never messed the steering up. I drove it home from the accident... Then had a local independent autobody shop fix it up for the "cash" price. The guy did a great job and the paint still looks new. I switched to the Legacy front grill & bumper during the repair job.

[NVAKeith]

Here in MD the semi annual emissions inspection is self service: pull up to a kiosk, scan registration card, swipe credit card, plug in OBD2 cable then it spits out the report.  The visual and safety inspection is just once, required for initial registration. 

[SubaruSquirrel]

On 2/27/2024 at 12:23 PM, NVAKeith said:

Here in MD the semi annual emissions inspection is self service: pull up to a kiosk, scan registration card, swipe credit card, plug in OBD2 cable then it spits out the report.  The visual and safety inspection is just once, required for initial registration. 

Wow, that's easy lol. Pretty much the same here, though. They just hook their inspection computer up to the obd2... There is no actual exhaust sniffer test.