CSF Auxiliary Radiators, BMW G8X M

Sold Individually. 2 Required for all applications.

The CSF High-Performance Auxiliary Radiators are a key addition to CSF’s proven G8X Cooling Suite for the BMW G8X M3, M4, and M2. While the factory auxiliary radiators perform adequately in stock form, increased power levels and sustained aggressive driving quickly expose the limits of the OEM cooling system. As S58 owners continue to push higher horsepower and harder track use, these auxiliary radiators are engineered to provide the additional thermal capacity required to keep temperatures under control.

With more than five decades of radiator manufacturing experience, CSF applies industry-leading design and testing to deliver dependable cooling performance for both street and track applications. These auxiliary radiators are built with 2-row cores utilizing CSF’s exclusive B-Tube Technology. Unlike conventional oval (“O”-type) tubes, CSF’s specially engineered “B”-shaped tubes are seam-brazed for superior strength and durability. This design allows the use of thinner, lighter aluminum while improving cooling efficiency. The B-Tube layout increases tube surface area by approximately 15% compared to traditional designs, effectively providing the heat transfer efficiency of two smaller tubes within the same space. Dual liquid laminar flow further enhances heat dissipation under high thermal load.

To complement the advanced tube design, CSF incorporates ultra-efficient multi-louvered fins that are precisely aligned to maximize airflow through the radiator core. Fin density and geometry are application-specific and validated through extensive wind-tunnel testing to ensure maximum heat rejection in real-world and motorsports environments.

The CSF G8X auxiliary radiators feature a true drop-in fitment with no modifications required. OE-style mounting brackets are CNC-machined and welded for long-term durability, and inlet/outlet connections are designed to match factory specifications, allowing reuse of OEM or aftermarket hoses. For high-horsepower builds and track-driven vehicles that demand reliable cooling performance, CSF auxiliary radiators deliver proven engineering, quality construction, and consistent results.

Details:

• Sold Individually – all applications require 2 auxiliary radiators
• Multi-Fit – Fits Both Left & Right Side
• 2-Row – 42mm High-Performance Core Featuring CSF’s Exclusive B-tube Technology
• Ultra Efficient 5mm Tall Fins with a Multi-Louvered Design for Maximum Surface Area Contact
• Tank Volume and Core Size Increased
• 100% All-Aluminum TIG-Welded Construction
• OEM Style “Quick Connect” Inlet/Outlet
• True “Drop-in Fit” Requires No Modifications to Install
• Includes Detachable Rock Guard
• Individually Leak and Pressure Tested
• High-Performance Upgrade Suitable for Professional Racing, Street Performance, or OEM Replacement
• Satin Black Finish for OEM+ Look
• 2 Year Limited Warranty

Applications:

• 2023+ G87 M2 S58
• 2021+ G8X M3 S58
• 2021+ G87 M4 S58

OEM Part Numbers: 

• 17118095285
• 17-11-8-095-285
• 17 11 8 095 285