The Karbonius E46 M3 CSL (S54) Carbon Airbox is engineered for enthusiasts who demand uncompromising performance, authentic motorsport sound, and OEM-level fitment. Inspired by the legendary BMW E46 M3 CSL, this carbon airbox delivers one of the most exhilarating induction sounds ever produced while unlocking meaningful power gains and sharper throttle response.
Manufactured entirely from 100% prepreg carbon fiber, the Karbonius E46 carbon airbox is autoclave-cured at 125°C in Spain under strict ISO 9001 quality standards. At just 1.7 kg, it offers an exceptional strength-to-weight ratio and represents one of the finest M3 CSL S54 carbon airbox solutions available today.
Precision Engineering Inspired by the Original CSL
Using advanced 3D scans of a genuine OEM CSL airbox, Karbonius has refined and enhanced the original design to improve airflow efficiency, durability, and performance:
Carbon Fiber Velocity Stacks
Replaces factory plastic trumpets with lightweight carbon fiber for reduced mass and increased rigidity.
Optimized Trumpet Diameter & Geometry
Enlarged 51.5mm trumpets (vs. 50mm OEM) with revised profiles improve airflow and cylinder filling.
Redesigned Sixth Trumpet
The traditionally airflow-restricted sixth runner has been reshaped to balance intake distribution across all cylinders.
Refined Internal Chamber
Hand-finished internal surfaces with sanding and clear coat reduce turbulence for smoother airflow and improved throttle response.
All aluminum components are CNC-machined and anodized, paired with stainless-steel hardware and aluminum threads for long-term reliability. Carbon weave orientation is carefully matched for a symmetrical appearance, while a neoprene foam gasket ensures a proper hermetic seal between airbox sections.
Performance Gains & Driving Experience
When paired with appropriate supporting modifications and tuning, the Karbonius E46 M3 CSL (S54) Carbon Airbox can deliver up to 25 horsepower gains, along with faster throttle response and an unmistakable motorsport induction sound that defines the CSL driving experience.
This M3 carbon airbox is as much about emotion as it is performance—transforming every drive into a visceral event.
What’s Included
Carbon Fiber Airbox Assembly
CNC-Machined Aluminum Components
Stainless-Steel Hardware
Ventilation Valve Bracket
M POWER Sticker
Numbered Certificate of Authenticity
For tuning recommendations specific to your setup, please contact IND Distribution sales directly.
Key Features
Noticeable horsepower and throttle response gains
Iconic CSL-inspired induction sound
Lightweight e46 carbon airbox design (100% prepreg carbon fiber)
Autoclave cured for superior strength and finish
Reinforced mounting points for long-term durability
Excellent fitment with straightforward installation
Aggressive CSL-correct appearance
Individually numbered for authenticity
Backed by a 2-Year Manufacturer Warranty
Vehicle Applications
BMW E46 M3 (S54)
BMW E36/7 Z3 M Coupe & Roadster (2001–2002, S54)
BMW E85 / E86 Z4 M (S54)
Installation Note:
Instead of installing a CSL-specific shortened oil dipstick, IND recommends rotating the factory dipstick approximately 180 degrees to provide proper clearance with the airbox.
Required IND Install Kit (Sold Separately)
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 & Bracket (for SMG-equipped M3 models)
Legal Disclaimer
This karbonius E46 carbon airbox is intended for off-road or motorsport use where applicable. It is the customer’s responsibility to verify local regulations regarding emissions and road legality prior to installation.