BMW M4 GT3

TYRES

• Slick (Dry) — Front: 27.5 PSI cold, Rear: 27.3 PSI cold. Tyre blanket temp: 80°C. Optimal operating window for peak grip: 85–95°C (front and rear) — qualifying lap should aim to cross the line with tyres entering this window at peak attack, front-left and rear-right biased due to Spa's mostly right-hand-dominant/left-load layout.

ELECTRONICS

• TC1: 3
• TC2: 2
• ABS: 4
• Engine Braking / Brake Magic: Medium-High (setting 6/10)
• Brake Bias: 54.5% front (base), adjustable -1.5% in-lap for La Source / Les Combes

SUSPENSION

• // FRONT
• Ride Height: 55 mm
• Wheel Rate FL / FR: 190000 N/m / 190000 N/m
• ARB: 110 N/m
• Brake Torque Multiplier: 100%
• Brake Bias: 54.5%
• // REAR
• Ride Height: 60 mm
• Wheel Rate RL / RR: 175000 N/m / 175000 N/m
• ARB: 85 N/m
• Diff Preload: 50 Nm
• Diff Coast: 0.5
• Diff Power: 0.65

DAMPERS

AERO

• Front Wing: 6 (of 10 clicks)
• Rear Wing: 7 (of 10 clicks)
• Downforce Level: High-biased rear for Eau Rouge/Blanchimont stability
• Brake Ducts: Front 4 / Rear 3 (single lap, minimal cooling needed)

KEY SETUP NOTE

• Rear ARB is kept slightly softer than typical ACC baseline to prevent snap oversteer over the Eau Rouge/Raidillon compression and Blanchimont — the M4 GT3's stiff chassis combined with a too-stiff rear bar will cause the rear to step out mid-compression at 280+ km/h; this single change is worth more than any aero tweak for a clean maximum-attack lap.

TRACK GUIDE

• La Source: brake extremely late (100m board, trail to ~40m), rotate hard on entry — BMW's front end accepts aggressive trail-braking well with 54.5% bias.
• Eau Rouge/Raidillon: full commitment flat in top gear if prior setup confidence allows; stay dead-center on the curbs, any lift unsettles the rear-biased aero platform — trust the stiffer front/softer rear ARB balance.
• Les Combes: this is where time is won — late, straight-line braking from Kemmel, hook the inside curb on apex, get back to throttle early for the short straight to Rivage.
• Pouhon: carry max minimum speed through both apexes — front wing at 6 clicks gives enough front bite without ballooning drag on Kemmel.
• Blanchimont to Bus Stop: stay flat through Blanchimont (rear stability is the whole setup's purpose here), brake hard and late into Bus Stop, use the aggressive curb-riding style on exit — traction out of Bus Stop is the last lap-time opportunity before the line.

THEORETICAL BE

TYRES

• Slick (Dry) — Front: 27.5 PSI cold, Rear: 27.3 PSI cold
• Tyre blanket temp: 80°C
• Optimal operating window (track temp): 85–100°C for peak grip; race stint target 90–95°C average to balance grip and degradation given aggressive kerb use at Eau Rouge/Bus Stop.

ELECTRONICS

• TC1: 4 (dry, aggressive but controlled traction on exit of Rivage/Bus Stop)
• TC2: 3
• ABS: 4
• Engine Braking / Brake Magic: Medium (setting 4/6) — helps rotation into La Source and Les Combes without snap oversteer
• Brake Bias: 54.0% front (base), adjustable 53.0–55.5% in-cockpit for fuel load changes

SUSPENSION

• // FRONT
• Ride Height: 65 mm
• Wheel Rate FL / FR: 155000 N/m / 155000 N/m
• ARB: 130 N/m
• Brake Torque Multiplier: 100%
• Brake Bias: 54.0%
• // REAR
• Ride Height: 70 mm
• Wheel Rate RL / RR: 145000 N/m / 145000 N/m
• ARB: 110 N/m
• Diff Preload: 60 Nm
• Diff Coast: 0.45
• Diff Power: 0.60

DAMPERS

AERO

• Front Splitter: 4 clicks (medium-high, stabilizes La Source/Les Combes braking)
• Rear Wing: 6 (of 10) — Spa-specific compromise favoring Kemmel top speed while retaining Eau Rouge/Blanchimont stability
• Downforce Level: Medium-High
• Brake Ducts: Front 4 / Rear 3 (manage temps under heavy braking zones, avoid overheating on long stints)

KEY SETUP NOTE

• The M4 GT3's biggest risk at Spa is rear instability through Eau Rouge/Raidillon compression and Blanchimont at race fuel loads — keep rear ARB softer (110 N/m) and rear ride height slightly higher (70mm) to avoid bottoming/snap oversteer; this sacrifices a fraction of rotation at Rivage but is essential for confidence flat-out through the two most demanding corners on track.

TRACK GUIDE

• La Source: brake late but progressively — trail brake to rotate the nose, avoid stabbing on entry as front tires already work hard here for 44 laps.
• Eau Rouge/Raidillon: commit flat in qualifying trim; in race trim with fuel/tyre wear, ease throttle 5-10% at the compression if car feels nervous — losing 0.1s here beats a race-ending crash.
• Les Combes: heavy braking stability is critical — brake in a straight line, use the stable brake bias to rotate mid-corner, get back to throttle early for Malmedy exit.
• Pouhon: this is where lap time is made — carry min speed through both apexes, trust the front-end grip from the splitter setting, resist lifting mid-corner.
• Traction zones (Rivage exit, Bus Stop exit): with