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This thread is for swapping a ’91-94 EJ22T into a stock ’89-94 NA/ non-turbo Legacy.

There are many other ways to turbo an NA car, but this thread is about keeping it as close to stock as possible, w/minimal wiring, and using original parts or from a ’02-07 USDM (US domestic market) WRX/STi. NASIOC is great resource for used parts, if not found on here.

When (not If) you find something I missed, either PM or just add a post and I'll update the original.

If adding a post w/Mods and Upgrades, e.g. MBC/bigger turbo/EM/etc., ensure you include ALL necessary parts so it's clear what it entails.


Things you should know:
- The turbo cars came stock w/better brakes and tires, among other things. Handling and braking upgrades should be done BEFORE an engine upgrade.
- Having a complete donor car is recommended, since you'll have the parts @ hand and you can see how it's setup.

The List:


• EJ22T Block, Intake Manifold (IM) w/fuel injectors, and Heads (heads have coolant and oil fittings for turbo):
o Turbo water pump
o Coolant and Oil lines for connection to head
o Other heads can be used (see Notes)

• Turbo
o Stock is VF11 (or VF10?) w/the 90° compressor inlet
o TD04 from WRX are readily avl. and w/the ’06-07 intercooler it is a good upgrade that doesn’t require tuning upgrades. Requires modification to PCV hoses and turbo compressor inlet hose.

• Fuel pump
o Used: Sti – 04-07 – may need install kit – Walbro # 400-791
o New: Walbro 255 – GSS341 use w/kit # 400-791

• Turbo Crossmember or cut/hack the NA crossmember for Up Pipe if using stock EJ22T exhaust manifold

• Turbo front sway bar if using Turbo Crossmember

• EJ22T exhaust manifold/header/up pipe (or any WRX/Sti from ’02-07?)
o Up pipe-usually comes w/exh. manifold (or any WRX/Sti -WRX has cat. conv. in up pipe)
o Bracket for turbo/up pipe

• EJ22T Downpipe (or any WRX/Sti from ’02-07?)
o O2 sensor bung @ top (right after turbo) is stock; OK @ end?

• Exhaust – Mid-pipe and axle-back. Includes catalytic converter/resonator and muffler. 2.25” is stock. Recommend 2.5”-3” tubing.

• Turbo Coolant Tank
o Requires additional plumbing
o WRX metal tanks are recommended upgrade.

• Turbo radiator mods:
o Turbo Radiator won’t fit in the NA location – too tall.
o The stock NA radiator works well but must modify the lines and radiator cap.
o There is a Post on here on HOW to set this up.....

• Harness- engine harness (has 3 plugs and runs from near battery and under the IM/on top of the engine) can be reused, but Coolant sensor and gauge wiring need extended.
o '90-'91 NA and '91 Turbo have the same 3-plug style (square); '92-'94 NA and Turbo are same (round). They can be swapped - just remember to do it BEFORE you install the IM, if it's off....IT CAN BE DONE w/OUT removing IM...I did it!!

• Turbo intake parts:
o Resonator box (usually deleted as part of ‘coffee cup’ mod)
o Inlet pipe from turbo to throttle body (if NOT using an intercooler) and using stock VF11
o Turbo ‘chimney’ – heat shield that attaches to turbo (requires a Legacy turbo hood w/scoop and shroud that the chimney connects to if going totally stock – recommend to use a WRX TD04 heat shield or turbo blanket/wrap instead.)
o Turbo compressor 90° intake hose
o PCV and Breather hoses

• Turbo IAC – Idle Air control (should be part of Turbo IM)
o NA one will work but its outlet (to the air intake) runs into turbo.

• Turbo Sensors – On passenger strut tower:
o Pressure Exchange, Boost Control Solenoid (BCS) (aka Wastegate Control), and MAP sensors

• Hitachi (metal) MAF Sensor
o No wiring changes required @ sensor or ECU if using Turbo ECU.

• Turbo ECU (ECU pin-out LINK)
o Requires additional wiring for Turbo Sensors
o Swap the Cam and Crank Positive pins @ the ECU
o Automatic and 5-speed manual ECUs are the same for ’91-94 turbos
o ECU plugs are the same - plug-and-play between NA and Turbo harness


• Legacy Turbo hood w/front air scoop (if using top- mount intercooler)
o ’91 interchange w/’89-91
o ’92-94 interchange w/’92-’94 (Sedan and Wagon are same)

*NOTES:
• Head options: Phase 1 EJ25 DOHC (requires oil and water lines drilled/tapped in head, or use alternate oil/coolant source) is a common upgrade. MUST have matching IM from DOHC.
o USDM - Phase 1 (aka Phase I) – ’89-98 EJ18, EJ22E, EJ22T, EJ25D engines. Phase 2 (Phase II) = 1999+ EJ22, EJ25, EJ20
o Exceptions: 1999 Legacy GT and Outback used a Phase 2 EJ25 block w/Phase 1 EJ25D DOHC heads.
o IMs are not interchangeable between SOHC or DOHC or different phases. BUT blocks and heads usually are interchangeable. Use the IM that matches the heads. Use the Head Gasket that matches the block – not the heads (in most cases).

• All '91-94 EJ22T's will work w/any transmission from '89-94. The flexplate/torque converter or flywheel must match the transmission.

Way off topic: And for the most part, any EJ-series engine (plus others) from ’89-’07 (?) will mate w/any transmission. BUT due to wiring differences Automatics are not as interchangeable as 5 (or 6) –speeds....the engines and transmissions will physically connect together, but due to changes in electronics over the years they won't work correctly.

• Timing belt pulleys, cam shaft sprockets/gears, and tensioner are the same between stock turbo and NA engines from '89-94 (and some newer); water pump is specific to the ’92-94 turbo, and the ’91 turbo also has an extra port on the water pump to feed the oil cooler only on the ’91 EJ22T. The ’91 should be the same part number as the USDM WRX.

Very nice. Good work.

Thank you! Thank you! Thank you! Thank you! Thank you!

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