Part Compatability

Cylinder Heads

1991-1992 model year cylinder heads do not have the requisite mounting points to attach the new style cam position sensor from 1993 and on, but the early style cam angle sensor will attach to the later style heads.

Therefore, a later head (93+) can be used on a 91-92 motor / vehicle with few issues (using the existing 91-92 hardware and sensors), however an early head (91-92) cannot be used on a 93+ vehicle without bringing the early cam angle sensor with the heads, and adapting the vehicle electrical system to support it.

Additionally, twin turbo model heads are equipped with oil squirters, while naturally aspirated DOHC heads are not.

Pistons

Twin turbo DOHC pistons have an 8:1 compression ratio while naturally aspirated DOHC pistons have a 10:1 compression ratio. Having the same diameter, they can be swapped without boring the cylinders, the shape of the piston head affects the compression.

Crankshaft

1991-1992 motors had cast cranks while 1993+ motors had forged cranks.

Fuel Injectors

Twin turbo DOHC injectors have low electrical resistance (2-3 ohms), while naturally aspirated injectors have higher resistance (13-16 ohms). Putting a low resistance injector into a system that expects higher resistance can damage the injectors, and doing the inverse will likely impede their ability to function properly.

Intake Manifold / Plenums

The lower plenum is the same between the naturally asiprated and twin turbo implementation of the DOHC motor. The upper plenum from the twin turbo model supports higher airflow, and can be swapped onto an naturally aspirated motor with no issues.

Mitsubishi Transmissions F5M33 / F4A33 (USDM / CADM Naturally Aspirated FWD)

2 main subsets of these transmissions exist for the platform:

• 25 Spline Axles (1991-1992 USDM/CADM)
• 27 Spline Axles (1993-1999 USDM/CADM)

If you want to change from one style to the other, you will need to also use the appropriate axles with the correct spline count.

If you want to change from automatic to manual, or manual to automatic, you'll need to bring the intermediate shaft of the driver side and the passenger side axle over even if they have the same spline counts.

Additionally, there is a subtle difference between the automatic transmissions used in the SOHC and DOHC motors:

• DOHC: 2200-3200 RPM Engine Stall Speed, 1.8 Stall Torque Ratio
• SOHC: 1800-2800 RPM Engine Stall Speed, 2.0 Stall Torque Ratio

Mitsubishi Transmission W5M33 / W4A33 (JDM Naturally Aspirated AWD)

The W5M33 (5 speed) uses a 3.545 gear ratio, while the W4A33 (automatic) uses a 3.307 gear ratio.

This section is a stub, it will be expanded in future updates.

Getrag Transmissions W5MG1 / W6MG1 (Twin Turbo AWD)

4 versions of the Getrag transmission exist for the platform:

• 5 Speed W5MG1 - 18 Spline (1991-Mid 1992 USDM/CADM, 1990-Late 1991 JDM)
• 5 Speed W5MG1 - 25 Spline (Mid 1992-1993 USDM/CADM, Late 1991-Mid 1993 JDM, 1993-Mid 1994 EUDM)
• 6 Speed W6MG1 - 25 Spline 3.307 Ratio (1994+ USDM/CADM)
• 6 Speed W6MG1 - 25 Spline 3.545 Ratio (Mid-1993+ JDM / Mid 1994+ EDUM)

If you want to change from one spline count to another, you will need to also use an appropriate transfer case with the correct spline count.

If you want to change anything other than a 1995-1996 Stealth R/T Twin Turbo from a USDM 6 speed to a JDM 6 speed, you will have to change your rear differential to either the one that came with the transmission (JDM 6 speed), or one from an all wheel drive / all wheel steering 3.545 ratio 5 speed car (any country twin turbo except GTO MR, or GTO SR Z16A chassis) model number J4G.

If you want to change a 1995-1996 Stealth R/T Twin Turbo from a USDM 6 speed to a JDM 6 speed, you will have to change your rear differential to either the one that came with the transmission (JDM 6 speed), or one from an all wheel drive / two wheel steering 3.545 ratio 5 speed car (GTO SR Z15A chassis, or GTO MR) model nuber J3G. You also have the option of using a J4G differential and performing an AWS delete on it.