The SW20 Turbo: A Chassis Ready for Better Suspension

The second-generation MR2 Turbo, produced from 1989 to 1999, came with a 2.0L 3S-GTE engine in later years. Despite its mid-engine layout and near-perfect weight distribution, the stock suspension was a compromise. MacPherson struts up front and Chapman struts at the rear left the car prone to lift-throttle oversteer and body roll during aggressive driving. Replacing the original shocks and springs — which are likely worn after decades — with a modern coilover kit corrects these shortcomings and unlocks a new level of driving pleasure.

Many owners note that upgrading to a BC Racing coilover kit is one of the single most effective performance upgrades for the SW20. It reduces squat under acceleration, controls dive under braking, and eliminates the unsettling wallow through corners. The result is a car that feels planted, responsive, and predictable at the limit.

Understanding Coilover Suspension

How Coilovers Differ from Standard Shocks and Springs

Traditional suspension uses separate shock absorbers and coil springs, often mounted on a strut assembly. The spring supports the vehicle’s weight and absorbs bumps, while the shock controls spring oscillations. A coilover combines a threaded shock body and a height-adjustable spring perch into a single unit. This integration offers two key advantages: ride height adjustability and independent damping control.

Key Benefits for the SW20

  • Ride height adjustability — You can lower the car to improve center of gravity and reduce aerodynamic lift, while still maintaining proper suspension geometry by keeping the control arms close to horizontal.
  • Damping force adjustment — BC Racing coilovers feature 30-click adjustable damping (rebound and compression on DS series, or monotube with multiple settings on BR series). This allows fine-tuning for street comfort or track aggression.
  • Monotube design — Unlike twin-tube shocks that overheat during sustained hard driving, monotube dampers dissipate heat faster, delivering consistent performance during track sessions.
  • Pillowball upper mounts — BC Racing includes front camber-adjustable pillowball mounts, which add negative camber for better cornering grip and reduce the need for aftermarket camber plates.

For daily driving, autocross, or open track days, a coilover system provides a direct connection to the road that the factory suspension never offered.

Why BC Racing Coilovers Are a Top Choice for the SW20 Turbo

Several suspension brands serve the MR2 community, but BC Racing has become a go‑to for good reason. Their kits are purpose‑built for specific chassis, and the SW20 kit includes application‑specific spring rates and damping curves. Here’s why enthusiasts consistently recommend BC Racing:

  • Material quality — BC Racing uses 6061 aluminum for the lower brackets and a cold‑drawn steel shock body coated in a double‑layer of zinc and powder‑coat to resist corrosion. The springs are made from SAE9254V steel, which resists sagging over time.
  • Non‑progressive springs — Many competitors use progressive springs that get firmer as they compress, which can cause unpredictable handling. BC Racing BR series uses linear rate springs for consistent, predictable cornering.
  • Lifetime warranty on damping — BC Racing backs their dampers against leaking or failure for the original owner, which provides peace of mind.
  • Bolt‑in installation — The kit requires no cutting, welding, or modification to the SW20’s suspension pickup points. For the front, the top‑mount bolts directly into the factory holes; at the rear, the lower clevis mounts to the knuckle with the original hardware.

For a real‑world comparison, many owners who have tried Eibach lowering springs on stock shocks report a harsh ride without adequate control. BC Racing coilovers solve that by matching spring rates to appropriate damping forces.

Installation Process: Step‑by‑Step Guide

Installing a BC Racing coilover kit on an SW20 is a weekend project for anyone with basic mechanical skills and a proper set of tools. Allow 6–8 hours for a first‑time install, including adjustment time.

What You’ll Need

  • Socket set (metric: 10, 12, 14, 17, 19 mm)
  • Combination wrenches
  • Torque wrench (capable of 50‑100 ft‑lbs)
  • Spring compressors (stock ones are tall; you may need compact ones for rear struts)
  • Floor jack and four jack stands (ratcheting preferred)
  • Penetrating oil (e.g., PB Blaster)
  • Alignment tools (string or camber gauge) for initial setup
  • Thread locker (Loctite blue 242)

Preparation: Removing the Old Suspension

  1. Safety first: Place the car on level ground, loosen the lug nuts, then jack up the front end and secure on jack stands. Repeat for the rear – both ends need to be supported for suspension removal. Use axle stands under the factory lift points near the subframe.
  2. Remove the wheels. For easier access, consider working on one corner at a time to keep the car stable.
  3. Remove the brake line and ABS sensor bracket from the stock strut. Do not disconnect the brake line – just unclip it from the strut body. Tape the clips to the lower control arm to prevent damage.
  4. Using a 14 mm socket, remove the two bolts connecting the strut to the steering knuckle (front) or lower arm (rear). On a SW20, the lower strut bolt at the front is notoriously tight; apply penetrating oil and use a breaker bar.
  5. Remove the top mount bolts: under the hood at the front, three 12 mm nuts around the top of the strut tower. At the rear, lift the carpet behind the seats to access two 14 mm nuts and one 12 mm nut.
  6. Extract the complete strut assembly from the car. It may require tilting the top of the strut forward while pulling the bottom out. Use a second set of hands if needed.

Disassembling the Stock Assembly (if reusing top mounts – usually not required with BC Racing’s included pillowball mounts)

With the assembly out, you must separate the spring from the shock. This is the only dangerous step — always use proper spring compressors. Place the assembly in a bench vise. Compress the spring using two compressors on opposite sides. Remove the top hat nut. Note: BC Racing kits include new pillowball top mounts, so you do not need to reuse the original rubber mounts. However, you may need to transfer the dust boot from the old shock if desired.

Assembling the BC Racing Coilover

  1. Loosen the locking collar on the BC Racing shock body. Set the spring perch to your desired ride height (start with manufacturer recommended: for SW20, typical drop is 1.5 inches front, 1.3 inches rear from stock height).
  2. Slide the BC Racing spring onto the shock body. Place the top spring cup and top mount. Ensure the bearing surface of the pillowball mount is clean.
  3. Thread the top nut onto the shock rod. Use a 10 mm Allen wrench to hold the rod while tightening the nut with a 14 mm box wrench. BC Racing specifies 30–35 ft‑lbs for this nut. Apply a drop of Loctite.
  4. Adjust the damping setting to the middle of its range initially (15 clicks from full stiff).

Installing the New Coilover

  1. Insert the assembled BC Racing coilover into the strut tower. At the front, you can place the top mount in the bay first, then guide the bottom into the knuckle. At the rear, it’s easier to install the coilover from below while a helper positions the top mount.
  2. Tighten the top mount nuts to 20 ft‑lbs. These are nylon lock nuts — do not overtighten as you can snap the studs.
  3. Attach the lower mount. For front: slide the clevis over the steering knuckle pinch bolt hole. Insert the 14 mm bolt and tighten to 94 ft‑lbs. For rear: use the 17 mm bolt through the clevis into the lower arm, torque to 87 ft‑lbs.
  4. Re‑attach the brake line and ABS wire brackets to the new coilover using the factory clips. Ensure the lines are not twisted and have full movement range.
  5. Repeat for all four corners.

Post‑Installation Checks

  • Lower the car to the ground and roll it back and forth to settle the suspension.
  • Measure ride height from the center of the wheel to the fender edge. Adjust perches as desired — usually a 13–13.5 inch front and 13–13.2 inch rear measurement (from center of wheel to fender lip) is common for a functional drop.
  • Before driving, cycle the steering lock‑to‑lock to check coilover clearance at full lock. Ensure no contact with the CV joints or frame.

Professional alignment is mandatory after coilover installation. The SW20’s suspension geometry is sensitive to ride height changes. A proper alignment with at least -1.5 degrees of camber front and -2.0 degrees rear will transform turn‑in and rear grip. For detailed alignment specs, refer to MR2 alignment resources like NTNOA.

Tuning Your BC Racing Coilovers

Setting Ride Height

Lowering too much can cause bump steer and reduced suspension travel. On the SW20, a drop of 1.2–1.5 inches from stock is ideal for street use. For track‑focused cars, 1.8 inches upfront and 1.5 inches rear works while maintaining functional geometry. Measure all four corners after settling, then re‑adjust if needed.

Damping Adjustments

  • Street driving: 18–22 clicks from full stiff (softer). Too stiff causes harshness; too soft gives excessive roll.
  • Autocross: 12–15 clicks front, 14–17 clicks rear. Stiffer rear helps rotation in tight turns.
  • Track: 8–12 clicks front, 6–10 clicks rear. Adjust based on understeer/oversteer balance.

Always make adjustments in pairs (both front axles same) and note that temperature changes affect damping. Test your settings on a safe stretch of road.

Corner Balancing

For serious performance, have a corner weight scale session. The SW20 can benefit from corner balancing to equalize cross weights, improving grip during left‑ and right‑hand turns. This requires professional equipment and is best done after initial height setting.

Real‑World Performance Benefits

Owners report that a BC Racing‑equipped SW20 Turbo feels like a different car. Body roll in corners is nearly eliminated. The car tracks accurately over bumps without unsettling the chassis. During high‑speed sweepers, the suspension stays planted, allowing earlier throttle application. On bumpy back roads, the monotube dampers keep the tires in contact with the pavement, increasing grip and driver confidence.

One common metric: lateral acceleration on Tire Rack test pads improves from ~0.88 g to over 0.96 g with proper coilovers and sticky tires. Additionally, the ability to add front camber via the pillowball mounts reduces inner edge wear on front tires — a common issue with lowered SW20s.

Maintenance and Longevity

BC Racing coilovers require minimal maintenance: occasionally spray the threads with a silicone lubricant to prevent corrosion and ease height adjustments. Check the locking collars every 5,000 miles to ensure they haven’t loosened. Inspect the pillowball mounts for play annually — they are sealed but can develop grit. If they become noisy, a rebuild is available directly from BC Racing for about $65 per damper.

Unlike many budget coilovers, BC Racing units are rebuildable and revalvable. If your driving style changes, you can have the damping curve modified to suit.

Conclusion

Choosing a BC Racing coilover kit for your SW20 Turbo is an investment that pays off in every driving scenario. The kit’s high‑quality construction, adjustability, and ease of installation make it the top recommendation in the MR2 community. Whether you’re looking to sharpen your autocross times, enjoy a weekend canyon blast, or simply refresh a 30‑year‑old suspension, BC Racing delivers. After installation, you will wonder why you waited so long. For additional information, visit the manufacturer’s official site: BC Racing Australia, or check out enthusiast reviews on platforms like MR2 Owners Club.