Understanding the Exedy Racing Clutch for the Evo 9

The Mitsubishi Lancer Evolution 9 is a performance icon, and its factory clutch is designed for daily driving, not sustained high-performance use. The Exedy Racing Clutch series offers a significant upgrade, providing increased clamping force, better heat dissipation, and a more aggressive friction material that can handle higher torque levels from modified engines. Whether you are running a stage 2 tune, a bigger turbo, or simply want more consistent launches, an Exedy Racing Clutch is a popular choice. Models like the Exedy Stage 1 or Stage 2 organic or cerametallic discs are common for street-driven Evos, while the Stage 3 and Hyper Single setups cater to track and drag use. This guide assumes you are replacing a worn clutch with an Exedy Racing unit, and we will cover the process thoroughly.

Tools and Materials You Will Need

Gathering the proper equipment before starting will save time and frustration. Beyond the Exedy Racing Clutch kit itself, you will need:

  • Exedy Racing Clutch Kit – includes pressure plate, disc, release bearing, pilot bearing, and alignment tool (verify kit contents before starting).
  • Socket and wrench set – metric sizes (10mm, 12mm, 14mm, 17mm, 19mm, 24mm for crank bolt if needed).
  • Torque wrench – ft-lb and in-lb ranges; essential for pressure plate bolts (often ~13–16 ft-lb) and flywheel bolts (~65–75 ft-lb).
  • Jack and jack stands – low-profile jack for the Evo’s 5.1-inch ground clearance, plus four stands for safety.
  • Transmission jack or heavy-duty floor jack with a wood block to support the transfer case and tail housing.
  • Breaker bar and extensions for stubborn bolts, especially the driveshaft center bearing bolts and downpipe bolts.
  • Flathead screwdrivers, pry bars, and picks for separating the shift linkage and wiring harness clips.
  • Clutch alignment tool – the Exedy kit typically includes one, but verify it’s the correct spline size for your 5-speed W5M33 transmission.
  • Brake cleaner, shop rags, and a wire brush for cleaning the flywheel surface and bell housing.
  • Threadlocker (medium strength) for pressure plate bolts if recommended by Exedy (check instructions).
  • Transmission fluid – Mitsubishi Genuine DiaQueen or approved 75W-90 GL-4; you will lose some when removing axles.

Preparation: Safety and Workspace Setup

Working under a vehicle is inherently dangerous. Park the Evo on a level concrete floor. Disconnect the negative battery terminal to prevent the engine from accidentally starting while you are under the car. Allow the exhaust to cool completely. Remove the battery and battery tray to access the transmission top bolts easily. Raise the car using a jack at the front center jacking point, then place jack stands under the four designated lift points (check your owner’s manual). Ensure the stands are rated for the weight (the Evo 9 weighs ~3,200 lbs) and are stable. It is a good idea to leave the jack lightly supporting the engine or transmission as needed. Drain the transmission fluid before removal to avoid spills when pulling the axles.

Step 1: Removing the Transmission

This is the most labor-intensive part. The Evo 9 uses a robust W5M33 transmission coupled with a transfer case. Follow these steps carefully:

  • Remove the downpipe and front exhaust section for access to the transmission bell housing bolts. Unbolt it from the turbo and separate the flange at the cat. Rest the downpipe aside.
  • Disconnect the driveshaft at the rear differential flange and unbolt the center bearing support. Slide the driveshaft rearward and tie it up out of the way. Do not damage the steering rack boots.
  • Remove the transfer case – drain it first (though you already drained the transmission). Unbolt the transfer case from the transmission (bolts are accessible from the driver side). Support it and pull it straight out. The input shaft may be a tight fit; a gentle pry may be needed. Set the transfer case aside in a clean area.
  • Detach the starter motor (two bolts) and move it aside. Disconnect the wiring connectors for the reverse light switch, neutral position switch, and speed sensor.
  • Remove the shift linkage – at the transmission, you will find a lever and a ball joint connection. Use a pick to release the retaining clip. Label all small parts.
  • Support the transmission with a transmission jack or a floor jack with a block of wood under the transfer case mounting location (the area where the transfer case stood). Be careful not to damage the aluminum casing.
  • Unbolt the transmission crossmember (the rear mount under the transmission). You may need to support the engine with a jack under the oil pan (with a wood block) to prevent it from tilting.
  • Remove the bell housing bolts. There are typically 10–12 bolts ranging from 12mm to 17mm. Access varies; some require extensions and universal joints. Note the locations of any ground straps or brackets.
  • Carefully slide the transmission rearward until the input shaft clears the flywheel. The transmission is heavy (approx. 75 lbs with transfer case removed). Work slowly to avoid binding. Once clear, lower the transmission and set it aside.

Step 2: Removing the Old Clutch and Flywheel

With the transmission out, you have clear access to the flywheel and clutch assembly.

  • Remove the old pressure plate by loosening the six bolts in a star pattern to prevent warping. The pressure plate may spring off – be aware of the diaphragm spring tension.
  • Remove the clutch disc – note the orientation (most discs have a "flywheel side" marking).
  • Remove the flywheel if you plan to resurface or replace it. The Evo 9 flywheel bolts are six 14mm head bolts, torqued to ~75 ft-lb. Use a breaker bar and a tool to lock the flywheel (such as a flywheel holding tool or a large screwdriver wedged against the ring gear). Some aftermarket flywheels use different bolt patterns.
  • Inspect and clean the flywheel – if original, check for heat spots, cracks, or scoring. If within spec, resurface it at a machine shop (remove a maximum of 0.010 inch). For an Exedy Racing Clutch, a smooth and flat surface is critical for proper break-in and life. Thoroughly clean the flywheel surface with brake cleaner and a lint-free rag to remove all oil and debris. Also clean the input shaft splines and the pilot bearing bore in the crankshaft.
  • Replace the pilot bearing – if your Exedy kit includes a new pilot bearing, use a bearing puller to remove the old one and a socket to press the new one in flush (do not pound it in; use a press or gentle tapping with a socket extension).
  • Replace the release (throwout) bearing – the new Exedy kit will include one. The Evo uses a hydraulic release system. Remove the old bearing from the clutch fork and install the new one. Some aftermarket bearings require a sleeve; refer to kit instructions.

Step 3: Preparing the Flywheel and Installing the New Clutch

Proper preparation ensures a long clutch life and smooth engagement.

  • Install the flywheel (if removed). Clean the crank flange with a wire brush. Apply a small amount of threadlocker to the flywheel bolts (check Exedy or OEM spec). Torque the bolts in a star pattern to the specified value. For a stock Evo 9 flywheel, this is typically 65–75 ft-lb. For aftermarket flywheels, follow the manufacturer's recommendation.
  • Deglaze the new flywheel surface – lightly sand the friction surface with 180-grit sandpaper and clean again. This helps the new clutch disc bed in. This step is especially important for new billet steel flywheels.
  • Install the clutch disc and pressure plate – use the Exedy alignment tool to center the disc on the flywheel. The disc must be correctly oriented (usually with the longer hub facing the transmission). Place the pressure plate over the disc and align the bolt holes. Install the six pressure plate bolts finger-tight.
  • Torque the pressure plate bolts – use a torque wrench and tighten in a star pattern to the Exedy specification (typically 13–16 ft-lb for the Exedy Stage 1/2 pressure plate; confirm with your kit). Over-torquing can warp the pressure plate. Some Exedy kits recommend a specific torque value printed on the pressure plate. Do not reuse old bolts – your kit should come with new ones.
  • Check the clutch disc alignment – after tightening, the alignment tool should slide in and out smoothly. If it binds, you may need to loosen the pressure plate and re-center.

Step 4: Reinstalling the Transmission

Reinstalling the W5M33 transmission can be challenging due to weight and alignment. Use these tips:

  • Clean the splines of the input shaft and apply a thin layer of high-temperature grease (avoid over-greasing – it can get on the clutch disc).
  • Lift the transmission and position it in front of the bell housing. Ensure the release bearing is properly seated on the clutch fork and that the fork itself is correctly positioned against the pressure plate diaphragm.
  • Align the input shaft with the clutch disc splines. You may need to rotate the output shaft slightly to engage the splines. Do not force it – if it doesn’t slide in, verify the clutch alignment tool was used correctly and that the pilot bearing is not misaligned.
  • Slide the transmission forward until it mates fully with the engine block. You should see the bell housing sit flush. Do not use the bolts to pull it together – that can damage the pilot bearing or input shaft. If it stops 1/2 inch short, check that the clutch disc is centered and that the transmission is not hanging on the clutch fork.
  • Install the bell housing bolts – hand-tighten them first, then torque to the factory spec (about 30–35 ft-lb for main bolts, 15–20 ft-lb for smaller ones). Refer to your Evo service manual for exact values.
  • Reinstall the transfer case – align the splines of the transfer case input shaft with the transmission output shaft. It may require rotating the output shaft. Bolt the transfer case using a star pattern to the transmission (torque ~35–40 ft-lb).
  • Reinstall the driveshaft – connect the center bearing support and the rear flange. Torque bolts to spec (typically 40–45 ft-lb).
  • Reinstall the starter motor, shift linkage, wiring connectors, downpipe/exhaust, battery tray, and battery. Do not forget the ground strap on the bell housing.

Step 5: Fluid Refill and Final Checks

Before lowering the car, confirm everything is correctly assembled.

  • Refill transmission fluid – the Evo 9 uses approximately 2.5–3 quarts of 75W-90 GL-4 (Mitsubishi DiaQueen or equivalent). Pour through the top fill hole until it starts to drip out. Do not use GL-5 fluid as it can damage the brass synchros.
  • Refill transfer case – use GL-5 80W-90 for the transfer case (about 0.75–1 quart). Different spec from the transmission.
  • Check clutch pedal feel – pump the clutch pedal several times to bleed the hydraulic system if you opened the slave cylinder line. Air in the system will cause a soft pedal. Bleed the slave cylinder if necessary.
  • Lower the vehicle – remove jack stands and lower to the ground with the jack.
  • Reconnect the battery – double-check all electrical connectors are secure.
  • Start the engine – let it idle for a few minutes, then test the clutch engagement in first gear. Listen for any unusual noises (chattering, rattling). A slight chatter is normal for some Exedy racing clutches, but excessive noise indicates misalignment or improper installation.

Clutch Break-in Procedure

Your new Exedy Racing Clutch requires a break-in period to achieve optimal performance and longevity. Follow these guidelines:

  • First 300–500 miles: Avoid hard launches, full-throttle shifts, and slipping the clutch excessively. Use smooth, moderate engagement from a stop. Do not ride the clutch.
  • Vary your driving speeds – do not maintain a constant speed for long distances during break-in. This helps the friction material mate evenly with the flywheel and pressure plate.
  • After break-in: Perform a few aggressive 3rd and 4th gear pulls to bed the clutch fully (do from 2,500 to redline under load). The clutch will then be ready for full use including launches.
  • Do not exceed the torque rating of your specific Exedy stage. The Stage 1 organic handles ~350–400 whp, while Stage 2 cerametallic can handle ~450–500 whp. Ask your tuner for recommendations.

Common Mistakes and Troubleshooting Tips

Learn from common pitfalls to save time:

  • Not replacing the pilot bearing – a worn bearing can cause noise and input shaft misalignment. Always replace it when doing the clutch.
  • Failing to resurface or replace the flywheel – an old flywheel with heat spots will cause chatter and poor engagement.
  • Mixing transmission and transfer case fluids – they require different specifications. Check your owner’s manual.
  • Not torquing the pressure plate bolts correctly – under-torquing can cause clutch slip; over-torquing warps the pressure plate.
  • Neglecting the alignment tool – if the disc is not centered, the input shaft will not engage smoothly, and you will damage the pilot bearing or disc hub.
  • Hard launches before break-in – will glaze the friction material and the clutch will never hold properly.

If you experience clutch pedal pulsation, check the flywheel runout (allowed maximum is 0.005 inch). If you have difficulty shifting, verify that the clutch disc is not dragging – this may be due to incorrect release bearing or improper slave cylinder adjustment (the Evo uses a self-adjusting hydraulic system, but air in the line can cause issues).

Why Upgrade to an Exedy Racing Clutch?

The factory Evolution 9 clutch is adequate for stock power levels, but high-performance upgrades demand more. An Exedy Racing Clutch provides:

  • Higher torque capacity – the Stage 1 organic holds 365 ft-lb, the Stage 2 holds 440 ft-lb, and the Hyper Single holds up to 600 ft-lb.
  • Improved heat resistance – the friction material and pressure plate design dissipate heat better during repeated launches and track sessions.
  • Consistent pedal feel – while heavier than stock, the engagement is predictable and allows for precise modulation during performance driving.
  • Longer life under hard use – when matched to your power level and driven correctly, an Exedy clutch can outlast a stock clutch by thousands of miles.

For more information on Exedy clutch specifications, visit the official Exedy website or consult your local performance shop. A helpful forum guide for Mitsubishi owners is available on EvolutionM.net, where you can find torque specs and owner experiences. For purchasing, check a reputable retailer like MAPerformance that carries Exedy kits specifically for the Evo 9.

Conclusion

Installing an Exedy Racing Clutch in your Evo 9 is a rewarding project that transforms the driving experience. While the process is labor-intensive and requires attention to detail, following this step-by-step guide will help you achieve a reliable installation. The key points are: proper flywheel preparation, correct clutch alignment, careful torque specifications, and a patient break-in period. With your new Exedy clutch, you will enjoy sharper shifts, the ability to handle higher power levels, and the confidence to push your car harder on the street or track.