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B4x Engine Specifications

Complete technical specifications for the BMW B48, B46, B48TU (Gen 2), B48TU2 (Gen 3), B48TU3 (Gen 4), B48E, B48R and related variants.

Compression Ratio by Model

  • 9.5:1 - B48E & B48R (M-Lite engines)
  • 10.2:1 - 30i model cars
  • 11.0:1 - 20i and 30e model cars

Core Specifications

Engine Block MaterialHeat-Treated All Aluminium (AlSiMgCu0.5)
Cylinder Head MaterialHeat-Treated All Aluminium (AlSiMgCu0.5)
Crankshaft MaterialForged C38+N2 (B48E crank is 1lb lighter)
Connecting Rod MaterialDrop-Forged Material
Piston MaterialCast Material (B48E has higher silicon content)
Bore Spacing91 mm
Bore Size82 mm
Displacement1,998cc (1.998 L)
Stroke94.6 mm
Compression Ratio9.5:1 (B48E/B48R) / 10.2:1 (30i) / 11.0:1 (20i/30e)
Connecting Rod Centre to Centre148 mm (B48E: 146 mm)
Crankshaft Offset0 mm
Main CapsB48E and B58 share same main cap (others different). Main journals 55mm
Cylinder Wall Plasma Arc Coating Thickness0.3 mm
Cylinder Wall Thickness Between Cylinders9 mm
Cylinder Wall Thickness (Thrust/Non-Thrust)9 mm

Valve & Timing Specifications

Intake Valve Diameter / Stem Diameter30.10 mm / 4.96 mm
Exhaust Valve Diameter / Stem Diameter28.5 mm / 5.95 mm
Maximum Valve Lift (Intake/Exhaust)9.9 mm / 9.7 mm
VANOS Adjustment Range (Intake)70 CA
VANOS Adjustment Range (Exhaust)60 CA
Intake Camshaft Spread122.5 - 52.5 CA
Exhaust Camshaft Spread120 - 60 CA

DME (Engine Control Unit)

B48 / B46MG1CS003
B48TU / B46TU / B48EMG1CS201 / MG1CS024
B48R / B48TU2 / B48TU3Unknown

M-Lite (B48E & B48R) Differences

  • -Lower 9.5:1 compression ratio (optimized for higher boost)
  • -Crankshaft is 1lb lighter than standard B48
  • -Pistons have higher silicon content
  • -Shorter connecting rod (146mm vs 148mm)
  • -Shares main caps with B58 engine
  • -B48E factory output: 225kW / 450Nm (2019-2024, discontinued)
  • -B48R factory output: 233kW / 400Nm (2024-Present, successor to B48E)

Video Explainer

Performance Upgrade GuideCommon Modifications