Turner Motorsport CSL SMG Aluminum Expansion Tank (21532282549) - E46 M3 S54
On SMG-equipped E46 M3s, the SMG fluid reservoir is integrated into the airbox assembly. As a result, upgrading to a CSL-style carbon fiber airbox requires a standalone expansion tank. While the Genuine BMW CSL SMG Expansion Tank is still available, it’s often difficult to source, and its weak plastic construction makes it prone to eventual failure.
With this in mind, our team of BMW enthusiasts went to work, designing a heavy-duty aluminum replacement that is built to last! Constructed from TIG-welded 5052/6061 aluminum and finished in a durable wrinkle black powder coat, this tank looks as good as it performs.
We've carefully crafted every detail of this expansion tank for a clean, hassle-free fit. Unlike the OEM tank, which mounts to the strut tower with self-tapping screws, our design uses pre-existing fastener locations for a completely reversible install. A slotted upper bracket lets you rotate the tank into position with the CSL airbox installed, freeing up room when you need to fit the airbox snout first. Our proprietary SMG pump inlet and fluorosilicone hose provide a sleek connection to the SMG pump, routing easily around the airbox and surrounding mounts. In place of the OE dipstick, an internal Turner logo tag serves as a max fill indicator, the same easy-read design used on all Turner Motorsport sheet metal expansion tanks.
Please ensure your correct model is selected
Does NOT fit your Change Vehicle
Fits your Change Vehicle
This product was last offered at the strikethrough price on
06-14-2026
Lifetime Replacement Program! Read more here
Product Details
On SMG-equipped E46 M3s, the SMG fluid reservoir is integrated into the airbox assembly. As a result, upgrading to a CSL-style carbon fiber airbox requires a standalone expansion tank. While the Genuine BMW CSL SMG Expansion Tank is still available, it’s often difficult to source, and its weak plastic construction makes it prone to eventual failure.
With this in mind, our team of BMW enthusiasts went to work, designing a heavy-duty aluminum replacement that is built to last! Constructed from TIG-welded 5052/6061 aluminum and finished in a durable wrinkle black powder coat, this tank looks as good as it performs.
We've carefully crafted every detail of this expansion tank for a clean, hassle-free fit. Unlike the OEM tank, which mounts to the strut tower with self-tapping screws, our design uses pre-existing fastener locations for a completely reversible install. A slotted upper bracket lets you rotate the tank into position with the CSL airbox installed, freeing up room when you need to fit the airbox snout first. Our proprietary SMG pump inlet and fluorosilicone hose provide a sleek connection to the SMG pump, routing easily around the airbox and surrounding mounts. In place of the OE dipstick, an internal Turner logo tag serves as a max fill indicator, the same easy-read design used on all Turner Motorsport sheet metal expansion tanks.
Features & Benefits:
- Allows for CSL-style carbon fiber airbox conversions on SMG-equipped E46 M3s
- Heavy-duty TIG-welded 5052/6061 aluminum construction provides a material upgrade over the failure-prone OEM plastic tank
- Durable wrinkle black powder coat finish
- Mounts to pre-existing fastener locations for a completely reversible install, with no self-tapping screws
- Slotted upper bracket allows for easy installation without requiring airbox snorkel removal
- Billet SMG pump inlet and fluorosilicone hose included for a clean connection that routes easily around the airbox
- Internal Turner logo tag serves as a max fill indicator, replacing the OE dipstick
Kit Contents:
- Aluminum CSL SMG Expansion Tank
- Billet Aluminum SMG Pump Inlet Adapter
- Fluorosilicone Fluid Feed Hose
- Installation Hardware
Product Development:
Our CSL SMG Aluminum Expansion Tank was designed, engineered, tested, and quality-inspected by our Research and Development team at our Wadsworth, Ohio, facility. We strive for the highest level of precision and quality through leading-edge product development technology, including FARO laser scanning for reverse engineering and quality inspection, SolidWorks 3D CAD modelling, rapid prototyping utilizing our in-house 3D printer, and rigorous long-term product testing.
Installation & Support:
Looking for installation instructions? Our team has assembled a start-to-finish installation guide, including detailed instructions on how to remove your factory parts. Click HERE for Installation Instructions.
Prop 65 Warning
- 21532282549
