Karbonius Composites CSL-Style Carbon Airbox for Exx BMW M3 / Z3 M / Z4 M

Karbonius Composites CSL-style airbox for the E46 M3 draws on the legend of the original CSL carbon intake celebrated for its induction note while delivering modern manufacturing quality. Weighing just 1.7kg, it is produced in Spain from 100% pre-preg carbon fiber and autoclave-cured at 125°C by qualified technicians under an ISO 9001 quality system. Based on 3D scans of a genuine OE CSL airbox, the design incorporates key improvements, carbon fiber trumpets for further weight reduction. Enlarged, reshaped trumpets (51.5mm vs 50mm) to enhance airflow, a re-engineered sixth trumpet to increase feed, and a smoothed internal chamber (sanded and clear-coated) to minimize turbulence. All aluminum components are CNC-machined and anodized with aluminum threads and stainless fasteners, and a neoprene foam gasket ensures an airtight seal between front and rear sections with matched weave orientation. Depending on supporting modifications and calibration, the system can yield gains of up to 25hp, sharpen throttle response, and produce a distinctive CSL-style induction sound.

Features

• Aerodynamically optimized design
• Guaranteed fitment with simple installation
• Reinforced at all critical points
• Distinctive, aggressive induction sound
• 100% pre-preg carbon fiber, autoclave-cured construction
• Individually numbered airbox with verified authenticity
• 2-year warranty

What’s Included

• Airbox
• CNC machined aluminum components
• Stainless-steel hardware
• Ventilation valve bracket
• M POWER sticker
• Certificate of authenticity

Applications

• BMW M3: E46 (2001-2006)
  [S54 – 3.2L I6]
• BMW Z3 M: E36/7, E36/8 (1997-2002)
  [S54 – 3.2L I6]
• BMW Z4 M: E85, E86 (2006-2008)
  [S54 – 3.2L I6]

Notes

• In lieu of installing the CSL-Specific Shortened Oil Dipstick, it is recommend keeping the stock unit and rotating it about 180 degrees so it clears the airbox
• Requires IND Install Kit:
  • OEM BMW M3 CSL IAT Sensor
  • Alpha N MAF-to-IAT Conversion Harness
  • OEM BMW M3 CSL Air Shut-Off Valve
  • OEM BMW M3 CSL Crankcase Vent Hose
  • OEM SMG Reservoir and Bracket for SMG-Equipped M3s

About Karbonius Composites

Karbonius Composites prioritizes uncompromising quality. Every component is produced in Spain from 100% pre-preg carbon fiber and autoclave-cured, using meticulous hand layup by highly qualified technicians under rigorous quality controls. Confident in its manufacturing standards, Karbonius provides a 2-year warranty against manufacturing defects. With extensive composites experience and a global base of satisfied customers, the brand is committed to delivering exceptional products and customer satisfaction. Each piece is individually numbered to verify origin and authenticity.