CSF High-Performance Auxiliary Radiators for F8X BMW F8X M2 Competition & M3 / M4 [8258]

CSF High-Performance Auxiliary Radiators for F8X BMW F8X M2 Competition & M3 / M4 [8258]

CSF stands as the leading cooling solution for BMW owners, particularly those with F8X M3 / M4 / M2 Competition models. Renowned for its expertise and unparalleled success in the cooling industry, CSF has introduced the final component to complete its acclaimed F8X Cooling Suite. While the factory auxiliary radiators perform adequately in stock configurations, their limitations become apparent under high-performance conditions and increased power levels. Recognizing the growing demand as S55 owners push their vehicles to new limits, CSF developed a solution to address these needs. Additionally, with the F8X platform nearing a decade in age and the newest models being at least five years old, many original coolers suffer from clogged or damaged fins, significantly diminishing their cooling efficiency.

Design & Engineering

CSF engineered its coolers as a true “Drop-in Fit” to ensure effortless installation. Each unit mounts directly in the factory location and utilizes OEM quick connections for seamless integration. The High-Performance Auxiliary Radiators complement the overall cooling system by effectively reducing temperatures and extending the heat soak threshold. This design helps maintain optimal temperature ranges, allowing enthusiasts to maximize performance without interruptions—avoiding the frustration of cutting a track session short for cooldown laps. Each CSF F8X Auxiliary Radiator is interchangeable between the left and right sides, with swappable fittings and plugs for easy setup on either side.

OEM vs CSF

CSF’s auxiliary radiators deliver a significant upgrade over the OEM F8X coolers. By eliminating the OE plastic mounting pod and integrating it into the modular design, CSF increased both the core size and tank volume. This enhancement results in approximately a 7% increase in Core Size and a 10% boost in Tank Volume. With a larger 2-row 42mm core, these radiators offer dramatically improved cooling efficiency and capacity. Featuring CSF’s Exclusive B-Tube Technology, the high-efficiency core maximizes airflow and heat dissipation for superior performance. Constructed entirely from 100% aluminum, the CSF units provide unmatched durability and performance. The stronger mounting pins and brackets replace the less reliable OE plastic pod system, while the sleek black finish adds extra protection and a stealthy appearance behind the F8X grilles. For added safety, CSF includes integrated bolt-on rock guards to protect the radiators from debris—mitigating the risk of punctures and fluid leaks, a common issue with OEM units. The modular design allows each auxiliary radiator to fit either side of the vehicle, offering several key advantages, especially for track applications. This design simplifies spare part management by reducing the need for side-specific units, saving both costs and space. For serious enthusiasts, having a single interchangeable backup radiator ensures greater convenience and readiness for high-performance driving.

Specifications

• Core Width & Rows:
  • CSF: 42mm (2-Row)
  • OEM: 41mm (1-Row)
• Number of Cooling Tubes:
  • CSF: 27
  • OEM: 24
• Number of Cooling Fin Rows:
  • CSF: 28
  • OEM: 25
• Fin Height:
  • CSF: 6.5mm
  • OEM: 8mm
• Design: 
  • CSF: 100% All-aluminum TIG-welded construction
  • OEM: All-aluminum construction

Features

• Sold individually (require 2 auxiliary radiators)
• Multi-fit (fits both left & right side)
• 2-row 42mm high-performance core featuring csf’s B-tube technology
• Ultra efficient 6.5mm tall fins with a multi-louvered design for maximum surface area contact
• Tank volume increased by 10% and core size increased by 6.4%
• 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

• BMW M2 Competition: F87 (2019-2021) – 3.0L TT I6 S55
• BMW M3: F80 (2015-2018) – 3.0L TT I6 S55
• BMW M4: F82, F83 (2015-2020) – 3.0L TT I6 S55

Notes

• Sold individually, requires 2 auxiliary radiators

About CSF

Back in 1947, a father and his three sons embarked on a business venture by setting up a small retail shop dealing in automotive parts. The family business blossomed over the years, evolving into an automotive garage specializing in radiator repair, and later, a radiator manufacturing facility. By 1975, the family-owned brand CSF was established, marking a milestone as the first to introduce import applications into the American automotive aftermarket, in line with the influx of Honda, Datsun, and Toyota vehicles. By 2009, the fourth generation of the CSF family joined the business, which had by then become a leading name in the import and domestic radiator and condenser markets, selling over 650,000 units that year despite an economic recession, and totaling over 35 million units to date. CSF’s portfolio expanded to include a diverse range of cooling systems, including commercial trucks, industrial and agricultural applications, marine coolers, intercoolers, pressure caps, and a pioneering Racing & High Performance Division. Today, CSF’s Racing & High Performance Division is renowned for designing and manufacturing advanced, efficient, and reliable cooling systems for a wide array of applications, from high performance all-aluminum direct-fit radiators to custom systems for racecars, power sports, off-road, marine, and industrial use. With over 50 years of experience and more than 40 million cooling systems sold worldwide, CSF has rightfully earned the industry title of “THE COOLING EXPERTS.”