Understanding the Bilstein B16 PSS10 Coilover System

The Bilstein B16 PSS10 is a monotube, height- and damping-adjustable coilover system designed for high-performance vehicles like the Mitsubishi Lancer Evolution. Its name comes from the ten distinct damping settings (0 to 9, with 0 being softest and 9 hardest), offering a wide range of adjustability for both street comfort and track aggression. The PSS10 uses a twin-tube rear damper design on some applications and a monotube front setup, but all versions feature an external adjustment knob for quick changes.

Unlike simpler “cup kit” systems that only lower the car, the PSS10 allows independent ride height adjustment without affecting spring preload or damper travel. This is critical because it means you can lower the chassis to your desired stance while preserving the full range of damper motion – leading to better bump absorption and control. For Evo owners, the PSS10 strikes a balance between daily usability and circuit performance when tuned correctly. Misadjustment, however, can lead to unpredictable handling, excessive understeer or oversteer, and even component wear.

Preparing Your Evo for Suspension Adjustment

Before any changes, mechanical preparation ensures consistent, repeatable results. Follow these steps:

  • Level Surface and Corner Weights: Park the car on a perfectly level floor. If possible, use corner scales to record weight distribution before and after adjustments. A mismatch of 5–10 kg across an axle can skew handling.
  • Tooling Up: You’ll need a torque wrench (Nm range), a 19mm wrench or hex key for locking collars, a measuring tape or ride height gauge, and a pen/marker to number damping settings. A spring compressor is not normally required for height adjustments unless you are swapping springs.
  • Tire Pressure & Wear: Cold pressure should be equalized left/right; uneven tire pressures mimic suspension problems. Check tread depth – a worn inner edge might indicate excessive camber rather than a suspension fault. Best practice: use a dedicated set of track tires if setting up for the circuit.
  • Inspect All Components: Look for loose bolts, leaking damper seals, cracked bushings, or bent arms. A damaged component will mask the effect of damping adjustments. Pay special attention to the top mount bearings, which should rotate freely.

Setting Ride Height Correctly

Ride height affects center of gravity, roll center geometry, and scrub radius. For an Evo (especially CT9A chassis), a good starting point is a 20–30mm drop from stock. Too low can cause the control arms to invert, leading to bump steer and rapid tire wear.

Step-by-Step Height Adjustment

  1. Measure from the center of the wheel hub to the fender arch (or ground to fender). Record all four corners.
  2. Loosen the lower locking collar using a spanner or wrench. Rotate the lower spring perch to raise or lower the vehicle. Turning clockwise lowers the car (on most PSS10 units – check the manual).
  3. Turn each corner until you achieve the target height. A common street setting is a 10mm difference front to rear (lower front) to reduce understeer.
  4. Re-tighten locking collars to the manufacturer’s torque specification. Never rely on hand-tightening; vibrations can shift the collar.
  5. Roll the car back and forth a few feet to settle the suspension, then re-measure. Repeat until consistent.

If you have adjustable sway bar end links, re-adjust them so the bar is neutral (no preload) at the new ride height.

Damping Adjustment – From Baseline to Fine Tuning

The ten settings on the PSS10 change both compression and rebound simultaneously. Setting 0 is full soft, setting 9 is full hard. For street use, 3–5 is typical; for track work, 6–8 might be used. Never run below 2 or above 9 for extended periods, as the valve stack may cavitate or overheat.

Finding Your Baseline

Start with all four corners at setting 5 – the midpoint. Drive a familiar stretch of road or a skidpad. Pay attention to:

  • Body roll in corners – too much roll suggests softer damping needed (or you may be running too low spring rate).
  • Nose dive under braking – should be controlled but not harsh.
  • Rear squat on acceleration – excessive squat indicates damper settings too soft or springs too soft.
  • Ride comfort – if it’s jarring over bumps, soften the affected axle first.

Tuning in Small Increments

Adjust one click at a time (front or rear axle only) and test. A single click can change the handling balance by several percent. For example:

  • If the car understeers mid-corner, stiffen the rear damping (increase number) by 1–2 clicks or soften the front.
  • If the car oversteers on throttle, soften the rear or stiffen the front.
  • If the car feels “floaty” on highway undulations, increase damping by 1 click on all four corners.

Keep a logbook: write down settings, tire pressures, track/road condition, and driver feedback. This helps you revert or evolve the setup methodically.

Alignment and Corner Weight: The Overlooked Factors

After adjusting ride height and damping, the suspension geometry changes. A proper alignment is mandatory. Here are typical target specs for a street/track Evo with PSS10:

  • Camber: Front -2.0° to -3.0°; Rear -1.5° to -2.5° depending on tire use.
  • Caster: +5.0° to +6.0° (as much as possible with offset bushings).
  • Toe: Front 0mm to 1mm toe-out; Rear 2mm to 3mm toe-in. For extreme track use, you may run slight toe-out front for turn-in.

Corner balancing (scales) is recommended after ride height is set. The goal is to equalize cross weights (left front + right rear = right front + left rear). This is done by adjusting ride height individually per corner. A corner balanced car behaves more predictably at the limit.

Track vs. Street Setup – Practical Differences

While the PSS10 is versatile, a single setup cannot excel on both bumpy streets and smooth circuits. You have two options: use settings 3–4 for street and 6–8 for track, or use the same settings but adjust ride height and alignment for one purpose.

Street Configuration

  • Damping: 3–5 depending on road quality. Softer reduces fatigue.
  • Ride height: moderate drop (20–25mm) to avoid scraping speed bumps.
  • Alignment: conservative camber (-1.5° front, -1° rear) for even tire wear.
  • Toe: slight toe-in at both ends for highway stability.

Track Configuration

  • Damping: 6–8. Stiffer controls body roll and quick transitions.
  • Ride height: lower (30–35mm) to lower CG, but check clearance with racing curbs.
  • Alignment: aggressive camber (-3° front, -2° rear). More castor if possible.
  • Toe: 0mm to slight toe-out front for turn-in, 2-3mm toe-in rear.

If you drive to the track, you may need to compromise. A good solution: set damping to 5 for the drive, then increase to 7 for sessions (five clicks takes about 30 seconds per corner).

Common Mistakes and How to Avoid Them

  • Neglecting preload: The PSS10 uses a split lower collar system – ensure the spring is not loose at full droop. If you hear clunking after adjustment, the preload may be too low or the locking collar not tightened.
  • Setting damping too hard: Many people turn to 9 expecting “race handling” but only get a jarring ride and loss of traction. The damper’s job is to keep the tire on the pavement – too much damping skips the tire over bumps.
  • Ignoring alignment: Even perfect damping and height cannot compensate for improper toe. Toe changes heavily impact tire grip and wear.
  • No documentation: It’s easy to forget what you last set. Use a notebook or a mobile app to track settings per session.
  • Over-adjusting one corner: Always adjust symmetrically unless you are compensating for a known weight imbalance (like driver-only in a left-hand drive car). Even then, make small changes.

Advanced Tips for Maximum Handling

For experienced drivers, consider these refinements:

  • Rebound bias: On the PSS10, the ten-clicks affect both compression and rebound. If you feel the car doesn’t settle quickly after a bump, you may need more rebound. But because they’re linked, some tuners recommend a “split” setup where front and rear have different clicks. Example: front 6, rear 5 can shift balance rearward.
  • Data logging: Use a GPS lap timer and accelerometer (like an Aim Solo or RaceCapture) to quantify changes. You might feel a change, but lap time tells the truth.
  • Spring rates: The PSS10 comes with specific spring rates for the Evo. If you change to stiffer springs (e.g., 10kg front / 8kg rear), the damping may become mismatched. Consult Bilstein for revalving or use stock springs.
  • Sway bar adjustments: A stiffer front sway bar complements the PSS10’s ability to reduce body roll, but you must adjust damping accordingly. A balanced car may need a softer front bar or a stiffer rear bar.

External Resources and References

For further reading and community-tested settings, consider the following links (opened in a new tab):

Conclusion

Achieving perfect handling with your Mitsubishi Lancer Evolution and the Bilstein B16 PSS10 system requires methodical adjustment, thorough preparation, and honest testing. Start with a baseline of 5, dial in ride height to your preference, then tweak damping one click at a time while evaluating the effect on body roll, traction, and steering response. Always pair suspension adjustments with a proper alignment and corner balance for the best results. Whether you are carving canyon roads or chasing lap times, the PSS10 can deliver a sharp, communicative, and compliant chassis—provided you take the time to understand its settings. Document your changes, learn what each click does to the feel of the car, and you will unlock the full potential of your Evo’s suspension.