My gradual conversion to an STi wagon was fast forwarded by the death of my stock 5MT, this is my write-up of the 6MT UK STi transmission in a 02 WRX Wagon. Previously, the wagon has had the engine swapped (JDM ver8 STi), interior (including seats), headlights and suspension with STi bits. The car is a daily driver and sees regular SM action.

The 04/05 (04 US) UK spec tranny is a great candidate for the 6mt conversion on a budget. The tranny can be had for the same price as a USDM/JDM tranny AND has the same transmission ratio and final drive as the stock US WRX. That means no rear diff swapping needed, and you can reuse your front axles. I know the rear diff is now a weak point, but keeping the rear bias near 50/50 will keep the rear from slipping during daily driving. A proper Sti diff (one exists for the r160) is a must (especially for auto and track use) and planned for this project.

Update with pictures below. Thanks to Roman for helping with the swap. I owe you one.

Parts list
------------
Transmission: 04 UK STi 6MT w/DCCD - The tranny and shaft were acquired from Simon (formerly of Prodrive, currently at Aerosim).

Clutch, flywheel and pressure plate: Stock USDM STi - It fits and I want to keep the clutch feel like stock. Also, after going through three WRX transmissions I want to have a forgiving clutch.

Driveshaft: 04 STi - The stock WRX shaft is longer and won't work.

DCCD Controller: neetronics PDC-01 - Programmable and less expensive than the stock unit.

Install (Important points)
-------------------------
For the most part the install was like a traditional tranny and clutch install.
- the driveshaft from the Sti is of larger diameter and the bolt holes on the flange that mates with the pinion of the diff are spaced further apart. I installed the driveshaft and lined it up with the diff, then spray painted the hole pattern onto the pinion. Then I drilled the four holes.
- I used the tranny mount and crossmember that came with the box. I don't know if the stock WRX crossmember is exactly the same.
- As pointed out earlier, you must use the Sti transmissions clutch release fork. Get it with the tranny if you can.
- I'll update this spot with the DCCD controller install.

First impressions
-------------------
WOW. I've noticed that the fact that the engine moves through the gears quicker it keeps the revs and the boost up. Boost between quick shifts comes on instantly. Even at 50% throttle the power is instant yet smooth through the revs. It's obvious the rear diff will be stressed when I get the car on course. It must be replaced. Even under normal street driving, when making a right hand turn and accelerating as the inside rear is light, you can hear that inside wheel spinning. Installing the DCCD controller will let me set a more rear-diff friendly bias.

Resources
--------------
Subaru gear ratios - http://www.rallispec.com/Transmission%20chart.htm
Aerosim - http://www.aerosim-research.com/
Neetronics - http://www.neetronics.com/neet/sensors-and-electronics/subaru-dccd-controller-2.html

Pictures
---------------

The different driveshafts:
http://images114.fotki.com/v636/photos/5/577568/2238191/IMG_0146vi-vi.jpg

Two trannies:
http://images18.fotki.com/v87/photos/5/577568/2238191/IMG_0160vi-vi.jpg
http://images18.fotki.com/v17/photos/5/577568/2238191/IMG_0164vi-vi.jpg

The numbers:
http://images19.fotki.com/v315/photos/5/577568/2238191/IMG_0165vi-vi.jpg

Getting the axles out of the way:
http://images16.fotki.com/v352/photos/5/577568/2238191/IMG_0168vi-vi.jpg

STi clutch and flywheel installed:
http://images115.fotki.com/v662/photos/5/577568/2238191/IMG_0143vi-vi.jpg

Nice. I always thought the 6MT was a better match for the 2.0.

hmm thats intersting i had never heard of a 6 speed w/ a 1 to 1.1 center diff

that sure removes a lot of work ...

where did you source the tranny?

Simon@aerosim had one posted up on the NASIOC Swap Meet. My original intention was a JDM tranny but when Simon mentioned he had a U.K. tranny, I jumped on it. He said he got it directly from FHI when in the U.K and put less then 7000 KM on it. He included a COOL WR1 knob.

Gear ratios:

UK/Europe/NZ Impreza WRX STi MY02-04 TY856WN*** 3.636 2.375 1.761 1.346 0.971 0.756 3.545 1.100 3.900 Viscous (4kgf)

US Impreza WRX MY02 TY754VN2AA 3.454 1.947 1.366 0.972 0.738 3.333 1.100 3.900 Viscous (4kgf)

Updated with photos.

did you add axels stubs or change axels? ... or am i not seeing the stubs on teh 6 speed

It has stubs. The 6-speed case is a mongster compared to the 5MT so you can't see teh stubs from the photos.

A man after my own heart. I am dreaming of an STi Wagon, so I will keep a watch out for future posts in this thread. Good luck with your project.

I too dream of an STi wagon. some day my bug eyed wagon will be a fire breathing STi with a roof rack

When the STi came to the states, and the wagon wasn't included, I wanted to build one. Functionally, I'm there and indeed it is a beast.

Check out some shots of the engine swap: http://public.fotki.com/rayesc/the_resurrection/

Shots of the wagon in action:
http://public.fotki.com/rayesc/my_cars/autox_photos/ (these shots were taken before coilover install so there's lots of lean and squat)

Outstanding!
I've been talking to Aerosim (and just met Steve and Simon for the first time last weekend) about converting my '02 wagon with '04 STi guts in August. :banana:

Nice Ray! I heard you took TTOD at the Z-Car Autocross.

Any chance you guys seen the code TY856WW7MA" ?

Me thinks it is 06 STI box with 1.1:1 stepper?

Did you didnt have to change the axles or rearend? If thats the case, I'll go with the UK 6spd, even though I like to gears in the JDM a little more.

...and now it gets better. Look what the mail man dropped off today...

http://images18.fotki.com/v87/photos/5/577568/2238191/IMG_0075-vi.jpg

:banana:

How do you like the PDC-01? No one seems to have done a write up on it yet?

...and now it gets better. Look what the mail man dropped off today...

http://images18.fotki.com/v87/photos/5/577568/2238191/IMG_0075-vi.jpg

:banana:

Lucky you!!
This is center, rear or front?
Mike

How do you like the PDC-01? No one seems to have done a write up on it yet?

And I will not be the first to do a proper write-up. Since the rear diff was my weak point, any rear bias would result in massive, diff snapping, wheelspin.

Since then I had to sell the Cusco diff before it was installed so I have yet to really drive the advantages the neetronics controller is supposed to give me. In my limited testing, it did what it was supposed to. That is take static values for several inputs to trigger the desired diff action based on those thresholds.

_ray

how much did the whole tranny upgrade run you?

$3300 for the tranny, flywheel, clutch and driveshaft. No other parts needed, did the work myself. Remember, the UK spec 6-spd does not require the whole rear-end upgrade.

neither does the 06+

Ohhh. the 06+ works on a EJ20*? Nice. How hard is it to get the whole super center diff (yaw, steering angle, tps) logic to work?

oh man I need an 06 sti trans!

impossible netronics ftw