BP9 6MT Manual Swap Guide

Posts specific to the 2.5 litre turbo engine

BP9 6MT Manual Swap Guide

Postby SuperS0nic » Wed Aug 04, 2021 4:47 pm

So after manual converting my car over July 2021, I've compiled this write up to help anyone else heading in the same direction.
For years people have said things like "You can't manual swap a BP/BL the floor is different, it's a full reloom job, the keys wont let the car start". There's some truth in all of this, but if you understand how the CANBUS system works and ignore all the people who post rubbish, you'll realise it's completely possible.


I am not a mechanic or Subaru specialist. The write-up and information I have provided is based off my own experience manual converting my car. I have tried to make this is as transparent as I can, but be aware that your experience may differ to mine. :)

Should I swap my car?

IMO you should only attempt this swap if you meet this criteria:

1. You have sufficient mechanic experience to undertake the job, it's very involved as it's a partial driveline swap
2. You have a car which if you sold and pay the difference for an equivalent manual, you would still have to pay more for the manual car
3. You have put enough time and money into your car to make it reliable with service history you are confident with (buying another car that is manual means you may not have any service history)
4. You have access to the proper mechanic spec equipment like a hoist and jack
5. You have the funds to do it properly

A reputable tuner in my area told me that in their experience, the Jatco 5EAT transmissions dyno at the wheels around 90KW on the 2.0L turbo, the 6 speed equivalent is around 140kw. In my case, the automatic in my car was edging on 400000kms and it showed. I also have put enough money into my car to make it reliable for daily driving and have no intention to sell it. This made it the perfect experiment for this swap.

In the next section, I will get into costs which is a big part of whether or not you should consider this as an option.

How much did it cost you?

Here is my costs as follows in NZD. Bear in mind, I did this swap with my dad and our friend who is a mechanic and was keen to let me use his hoist and tools. Prices will vary but use it as a guide:

Full Conversion kit $3250
New Exedy Clutch $780
Axle Seals x1 $7.10
Rear main seal $16.92
Oil $254.68
Flywheel machine $100
CV Boot repair $100

Expect a standard reflash cost for the tuning side if you go that route. In my case, my tuner was happy to do it to see if it was possible and we were delighted to find it did work. A custom map was more or less needed for mine therefore I have omitted this cost.

What's the CANBUS situation?
In gen 4 onwards Legacys/Libertys, the ECU, cluster and key barrel and coded to work as one unit as part of immobilisation. If one of these units is different to the others, the car will not work. This affects manual swapping because an auto ECU does not have mapping for a manual car. There is 3 ways around this I see:

1. Full cluster, key barrel with locks and ECU swap from manual donor
2. ECU swap from manual donor and reprogram CANBUS code via Subaru dealer.
3. Flash manual ROM onto auto ECU.

In my case, I went with option 3 as in NZ, 2.5 Spec.B NZ New cars are very rare, more so as a manual. Pick whatever option is most suited to you. I have heard of success with option 1 also, however at this stage option 2 is more in theory. I can not guarantee it will work.

If you are prepared to undertake the challenge, follow on and I'll show you how I did it!
Photos link available at bottom of post

Part One: Getting the right parts

First and foremost, the boxes between EZ30 and EJ20/EJ25 are different in some regards so for the best result, seek out a conversion kit which came off the same car as yours. Or if buying a whole donor, get a donor the same as yours. This saves any headaches with potential unseen and small differences. EJ20/EJ25 cars use the R180 and aluminium diff brace, EZ30 cars have an R160.

The list of parts required are as follows:
-6 speed gearbox
-shifter complete
-cross member
-one regular size bell housing bolt (auto starter and bell housing has a longer bolt that doesn't fit the manual)
-manual starter motor
-clutch and flywheel assembly with all bolts
-slave cylinder
-master cylinder
-clutch lines
-clutch pedal box complete with appropriate switches
-clutch pedal retainer bracket
-manual brake pedal
-shift boot and gear knob
-shifter insulation with shifter frame
-rear diff with CV axles
-rear diff matching cradle
-matching downpipe (if twin scroll, single scrolls are the same downpipe)

-all relevant bolts from donor vehicle
-2 core wire lengths
-soldering equipment
-spade terminals with crimp tool
-6mm plate steel with suitable bolts, washers and nuts
-gearbox oil

If you have any oil leaks inside the bellhousing or other areas that would normally be hard to access, this would be a good time to replace the seals. Add these to your cost, rear main make the most sense to replace at this time. It's also cheap insurance to do a flywheel resurface or buy new as well as a brand new clutch. It's cheap insurance and if you're going to the effort to swap, do it once and do it right.

Part Two: Removing the 5EAT

First step with any Subaru manual conversion is to remove the automatic from the car. This includes the CV axles, exhaust, rear diff, driveshaft, auto trans cooler lines and shifter. Intercooler has to be removed in order to access the bell housing and pitch mount. Put a rag in the turbo to prevent stray objects entering. Undo the pitch mount, bellhousing bolts and remove the starter. Unbolt the top of the downpipe at the turbo. Unplug the auto trans plugs and remove the ground wire. Under the car, remove the CV axles, exhaust, heat shields, driveshaft and disconnect the shifter cable from the shifter. Drain the ATF from the bottom bung. Cut the auto trans cooler lines on the radiator and loop the two ends once the fluid is all gone. The hard lines and filter can be unbolted and removed once the auto is gone from the car. Remove the 4 12m bolts that bolt the flex plate to the torque converter, these can be found behind the black plug on top of the motor on the bellhousing.

Inside the car, remove the ring from the shifter, aswell as the dash trim pieces that secure the cover panels. Unbolt the 2 bolts at the back of the centre console. Remove the cover panels as needed and pull back the console. Unbolt and unplug the auto shifter and remove from the car. Keep the bolts as they will be reused.

Secure the auto to a trans jack, unbolt the crossmember from the car and carefully wiggle free the auto. The torque converter may get stuck so take your time and be gentle. Once it is out, place it to the side and remove the flex plate from the motor.

Part Three: Fitting the 6MT

Begin by preparing your flywheel, replace the pilot bearing and clean surface with brake cleaner to remove and contaminants. On the gearbox side, I removed the o2 sensor wires from the auto and swapped them onto the manual box so it plugs back into the factory loom the same. Ensure the bellhousing is clean and apply a small amount of grease to the input shaft, snout and release fork shaft. Install the new release bearing clip side out towards the back of where the engine will be. (I was tired and put it on backwards so make sure this is right, otherwise it's gearbox out again). Reinstall the release fork and shaft and screw down the cap to lock it in place.

Now is the perfect time to inspect the rear main seal for leaks, mine was just starting to weep so it was replaced. Bolt on the flywheel and clutch to the correct torque spec. Secure the gearbox to the transmission jack. It is best to have the slave cylinder and shifter removed to make fitment easier. Remove the two plastic bungs at the bottom of the firewall that fill in the holes where the crossmember will bolt up to. Jack the trans up carefully and locate on the lower studs. A high jack stand on the bottom of the motor makes getting the angle easier. Slowly ease the gearbox onto the back of the motor and rotate the flywheel if needed to help align the clutch and input shaft. Do not force it, be careful and go slow so ensure you don't damage anything. Once the two have located, reinstall the bellhousing nuts and bolts as well as the starter and the assembly will pull together. Bolt up the two front crossmember bolts. Reattach the shifter and remove the two small bungs in the trans tunnel and bolt the rear support up. I used two of the 12mm flex plate bolts for that. Refit the front CV axles and indent the nuts. Drain the gearbox oil and refill with fresh oil.

Part Four: The Adaptor Plate

The brace in the floor the rear crossmember is bolted to is further back in the 5EAT cars compared to the manual cars and 4EAT. The options to get around this are to:

A: Cut and extend the manual crossmember so it reaches
B: Fabricate an adaptor plate to bridge the gap

I went for option B give its easier and can be made to suit the auto crossmember. From what I have seen there are atleast 2 different kinds of manual crossmember. One has an enclosed section, the other is open pressed steel. The bolt patterns on both are different, which is why I believe the plate is the better option because it can be made to suit easier.

For the plate, I used 6mm mild steel cut into a 140mm x 150mm piece. Along the 140mm axis, 2 10.5mm holes are drilled 60mm apart with the edges of the left hand side hole 15mm in from the top side and left hand side. From this the plate can be bolted up to the gearbox side. The automatic cross member with the mount remove can be re attached to the car (keep the small bolts on the crossmember towards the rear of the car, they're for the exhaust heatshield). I used a clamp to hold the plate and auto crossmember together in the right location. Once I was happy the two were aligned straight, I marked the holes for the auto crossmember in the plate and drilled them out. After that the plate was removed and given a coat of paint before final install. The end result is strong and looks good.

(Side note: for the reason of the crossmember having variations, I am unable to reliably produce any bridge plates as I have no information on what the differences are between models.)

Part Five: Rear Diff and Axles

This is a little harder than the older Subarus but isn't too bad. We unbolted the multi links on the drivers side and pulled the hub out of the way. With the CV removed on one side, the diff was unbolted at the front and rear mounts. Undo the CV nut on the other side and slide the diff and passenger CV out as one. Install the new passenger CV, feed the end into the new diff and seat the end of the axle. Once it locates, bolt up the new diff. It is best to use the diff mounts from the donor diff and bolt it up as one. If your swap has an R180, the front mount wont match the smaller diffs hence why I say this. Now you can slide in the new drivers side CV and locate the axle inside the diff. Once it too locks into place, pop the other end into the hub and reattached the multi links. Bolt on the CV nuts for either side and indent. Once that's all done, you can refit the tailshaft, heatshields and exhaust. Plug the o2 sensor back into the wires on the gearbox. I replaced the downpipe gasket while I was in there. Be sure to drain the old diff fluid and refill with fresh oil.

Part Six: Pedals

First step of this is to remove the cover panels under the dash to expose the wires and pedals. Unplug the TCU, remove the relays and unbolt it from the car. The clutch pedal assembly bolts into where the TCU was. The clutch master is fed through the other side and the bracket on the rod end slips over either side of the pedal. Fit the pin and hair clip. Bolt the master on from the other side. Bolt up the two piece retainer that bolts up under the dash above the clutch pedal. Bolt on the retainer bracket the goes under the dash above the clutch pedal.
The brake pedal is just removed at the top pivot and the pin and hairclip are removed. Fit the manual brake pedal, the mounting box does not need to be removed. Refit top bolt and tighten as well as the pin and hairclip. If your car has cruise control, this is where you will need to make sure that the appropriate switch is on the clutch pedal. The brake switch for the cruise control will still be on the original brake pedal box so it is already good to go. Remove the automatic dead pedal and fit the manual one, you will need to cut the carpet a bit to do this.
Fit up the clutch hard and soft lines as well as the clutch slave cylinder to the trans. To engage the release bearing, the clutch fork is pushed to the rear of the car and it will click into place. Bleed up the clutch pedal.

Part Seven: Shifter and final mechanical

Using the auto shifter bolts, bolt down the manual rubber boot and steel ring to the top of the shifter tunnel. I pulled apart the auto shifter and found the switch that controls the ignition key lock, it is located where the lever would be if the car is in park. I traced the wires back to the plug on the auto shifter and cut the plug off. The other wires were removed from the plug leaving the two for the key lock which were soldered together and covered with heat shrink. The plug is then plugged back in and this will allow the key to release from the ignition. Once that's all sorted, you can refit the factory insulation.

Part Eight: Wiring


For the wiring side, it is best to leave the intake side off still and the centre console apart so you can access everything easier. I plugged the transplanted o2 wire back into its original plug on the factory loom.

Reverse Lights and Neutral Position Switch

I bought a couple rolls of two core wire and soldered them onto the factory neutral position switch (NPS) and reverse light (RL) wires and covered them up in tape and insulation. These were then fed into the car using a spare bung in the firewall. The wires for the reverse lights and routed to a relay mounted to the TCU. There is two of them, so with the battery on you will need to test them by bridging the larger terminals on each to see which one is which. The other relay can also be removed and left as it looks to be a power supply for the TCU. Once you know which is the relay for the reverse lights, I soldered on two spade terminals to the wires from the engine bay and plugged them in to the larger terminals. The whole relay was then covered with electrical tape and ziptied to the retainer bracket above the clutch pedal.

The Neutral Position Switch wires were then run under the dash trim and behind the stereo to the passenger footwell and to the ECU. One of the wires was soldered to the ECU side of the C31 wire, the other was spliced into one of the wires coming off the B122 joint connector. I used C6 on the ECU, spliced into that, soldered and taped up. FSM: (E/G(TB)-14)

Starter Relay

For this I made a small wire with two spade terminals soldered to either end. In the relay box beside the fuse box, there is a relay with two larger wires coming off it. This is for the starter relay. Plug the spades into the connectors for the larger wires. This hard wires the car so it will start. FSM: (E/G(TB)-04)

Manual ID Pin

I got a pin the correct size for the ECU plug and attached a wire onto the end. The pin is fed into the C15 location on the ECU and the wire was spliced into the A5 wire on the ECU. Solder and cover with electrical tape. If you need a pin, cut off an ECU plug from a wrecked car and cut it open and pillage a pin from that. (See Engine Electrical System Wiring diagram)

Cruise Control Clutch Switch (Cruise Control Cars Only)

Another two core wire was soldered onto the switch on the clutch pedal. This was fed on the same path as the NPS wire to the ECU. The C25 wire is in the auto loom, it gets cut in half and the switch wires go on either end. This means that when the clutch pedal is pushed in while cruise control is active, the circuit breaks and the cruise control cancels.

Once you are happy that your work is tidy and your wires test correct for continuity, reassemble the rest of the car. Reinstall all the interior and the intake in the engine bay. Make sure that your starter wires are all on, trans ground wire is on and your intake is secure with no leaks. By now the car will start and run with no automatic computer. It is critical that you check over all your work before starting the car to make sure everything is put back together properly. The speedo will be controlled by the ABS speed sensors so there is no wires for those. FSM: (E/G(TB)-05)

You can also remove the automatic paddles, this requires the steering wheel to be removed to do so. I recommend looking up steering wheel removal on these cars first to ensure you don't accidentally set your airbag off.

Part Nine: Tuning and Break in

Once you have the car started and running with no leaks or issues, you can break in the clutch as normal. Be aware that the car will not run properly as it will want to throw error codes and not boost.

This is when you will need to have a manual map flashed on. I spoked to Amit Lal from Custom Culture and Tuning in Auckland and we got together one morning and flashed a manual map onto the ECU. Once this is done, the car should be good to go! If you have cruise control, test that the clutch pedal cancels when depressed and that is also cancels when the shifter is pushed into neutral without the clutch (on low load). You now have a running and driving manual BP/BL Legacy.

On the whole I am over the moon with mine. The car edged into 400000kms with a 6 speed manual box and the car drives so much better as a result. It is more responsive, pulls hard and uses less fuel that the automatic gearbox did. I am yet to see another 2008 NZ New 2.5 Spec B with a 6 speed and in diamond grey so I think it has made my car even more of a unicorn that it already was.



Pongakawa Motors


https://www.youtube.com/channel/UCFUBt5 ... 8XBIh4RtNA

https://drive.google.com/drive/folders/ ... sp=sharing


Last edited by SuperS0nic on Thu Oct 21, 2021 9:21 am, edited 1 time in total.
2008 Subaru Legacy 2.5GT Spec.B NZ New
Manual Converted
Posts: 19
Joined: Sun May 30, 2021 5:20 pm
Car: 2008 Subaru Legacy 2.5GT Spec.B

Re: BP9 6MT Manual Swap Guide

Postby bigBADbenny » Thu Aug 05, 2021 8:14 am

Super superb! Thanks :good:

Iirc NVMLYH 3.0 SWAP thread linked above has adapter plates template ;)
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Re: BP9 6MT Manual Swap Guide

Postby SuperS0nic » Thu Aug 05, 2021 4:40 pm

It does but it didn't match my car, hence why I couldn't provide a template and did it on the car. The orientation of the crossmember side bolt holes on that plate look to be inverted, which could be an EJ vs EZ thing. But I know aswell that the prefacelift ones are different again
2008 Subaru Legacy 2.5GT Spec.B NZ New
Manual Converted
Posts: 19
Joined: Sun May 30, 2021 5:20 pm
Car: 2008 Subaru Legacy 2.5GT Spec.B

Re: BP9 6MT Manual Swap Guide

Postby bigBADbenny » Thu Aug 05, 2021 6:05 pm

Oh damn. Plot thickens again!
But ultimately in a good way :)
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Re: BP9 6MT Manual Swap Guide

Postby EJ20Wagon » Mon Nov 01, 2021 12:53 pm

How much did it cost you to get it tuned ?
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Re: BP9 6MT Manual Swap Guide

Postby SuperS0nic » Sat Nov 13, 2021 2:10 pm

Couple hundy I think or there abouts. It was an experiment with my tuner so I can't really give an accurate cost. But at a basic level it's just flashing a manual map theres no tricks to it really.
2008 Subaru Legacy 2.5GT Spec.B NZ New
Manual Converted
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Joined: Sun May 30, 2021 5:20 pm
Car: 2008 Subaru Legacy 2.5GT Spec.B

Re: BP9 6MT Manual Swap Guide

Postby rexhunta » Tue May 17, 2022 6:03 pm

I have been rewatching a heap of old MCM videos from when Alan was at AM Autos and they built Gramps, and when Marty was messing around with his RS turbos. Without either of both these dudes I definitely would not be able to work out 1/2 of what i've been able to achieve.

I've just grabbed some of your info for my auto to manual conversion, the wiring has helped a bit, thanks.
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