BMW F8X M3/M4/M2 Comp High-Performance Auxiliary Radiator

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Like the other cooling systems on the F8X, the factory auxiliary radiators do a pretty good job in stock form. However, once you start adding a lot of power and pushing the car in aggressive driving conditions, the factory systems start to show its limitations. As more and more owners have pushed the limits of their S55, CSF saw the need and demand. The F8X platform is also almost a decade old with the newest examples being at least 5 years old. Over time the original coolers end up with damaged or clogged fins that greatly reduce their cooling capacity.

Compared to the OEM F8X coolers, the CSF units are a significant upgrade. CSF eliminated the OE plastic mounting pod by incorporating it into the modular design that fits both sides. This design improvement increases the size of both the core and tanks. The extra space taken from the mounting pod allowed for a ~7% increase in Core Size and an ~10% increase in Tank Volume. With a larger 2-row 42mm core, cooling efficiency and capacity are drastically increased. The high efficiency core using CSF's Exclusive B-Tube Technology maximizes airflow and heat dissipation. 100% All-Aluminum construction ensures the best performance and durability. The mounting pins and brackets are much stronger and more durable than the OE plastic pod mounting system. In addition, the black finish provides extra protection and offers a stealthy look behind the grilles of your F8X.

Product Details

Design & Engineering

CSF designed the coolers to be a true "Drop-in Fit" for easy installation. Each cooler mounts in the factory location and uses the OEM quick connections. The High-Performance Auxiliary Radiators work in conjunction with the rest of the cooling system to reduce temperatures. They not only help keep temperatures in optimal ranges, but prolong the heat soak threshold. There's nothing worse than having your track session cut short because you need to do a cooldown lap.

Each CSF F8X Auxiliary Radiator can fit the left or right side. The fitting and plugs are swappable and can be easily set up for either side.

OEM vs CSF

Compared to the OEM F8X coolers, the CSF units are a significant upgrade. CSF eliminated the OE plastic mounting pod by incorporating it into the modular design that fits both sides. This design improvement increases the size of both the core and tanks. The extra space taken from the mounting pod allowed for a ~7% increase in Core Size and an ~10% increase in Tank Volume. With a larger 2-row 42mm core, cooling efficiency and capacity are drastically increased. The high efficiency core using CSF's Exclusive B-Tube Technology maximizes airflow and heat dissipation. 100% All-Aluminum construction ensures the best performance and durability. The mounting pins and brackets are much stronger and more durable than the OE plastic pod mounting system. In addition, the black finish provides extra protection and offers a stealthy look behind the grilles of your F8X.

Feature	OEM	CSF
Core Width & Rows	41mm - 1-Row	42mm - 2-Row
# Cooling Tubes	24	27
# Cooling Fin Rows	25	28
Fin Height	8mm	6.5mm
Design	All-Aluminum Construction	100% All-Aluminum TIG-Welded Construction

In addition, the CSF auxiliary radiators also feature integrated bolt on rock guards to keep the coolers safe. You've no doubt heard horror stories about OEM coolers getting punctured and spilling fluids all over the road or track. Now you can feel more confident that your cooling system is safer from road debris.

Modular Design

CSF used a modular design so the auxiliary radiator can fit either side. There are several benefits to this type of design and it offers several benefits. One of those benefits is for serious track applications. Having spare parts is always a great idea. Having one auxiliary radiator that fits both sides where you'd normally need one of each is a big cost and space saver. Getting an extra as backup is more cost/space efficient with the CSF units.

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F8X S55 Cooling System

The F8X S55 cooling system is decently complex. Diagrams have been included for anyone who doesn't understand how the whole system flows.

The cooling system consists of 6 to 7 heat exchangers depending on your transmission. Numbers below refer to the graphic above.

1. Auxiliary Radiator (Right Side) - Charge Air Cooling System: CSF #8258 - High Performance Auxiliary Radiator

2. Radiator - Engine Cooling System

3. Front Mount Heat Exchanger - Charge Air Cooling System: CSF #8075/8075V - High-Performance Front Mount Heat Exchanger

4. Charge Air Cooler - Charge Air Cooling System: CSF #8082 - Dual-Pass Top Mount Charge-Air-Cooler

8. Auxiliary Radiator (Left Side) - Engine Cooling System: CSF #8258 - High Performance Auxiliary Radiator

9. Engine Oil Cooler: CSF #8220 - High-Performance Engine Oil Cooler

10. DCT Transmission Cooler: CSF #8081 - Dual-Pass Race-Spec DCT Transmission Cooler

Because each auxiliary radiator is used for a different system you can elect to replace one at a time. For those looking to further improve the Charge Air Cooling system replace the right side auxiliary radiator. Those looking to improve the engine cooling system should replace the left side.

Charge Air System (5 – right side auxiliary Radiator)

Engine Cooling System (1 – Left side auxiliary Radiator)

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Installed Images

Perfect drop-in fit in the factory location. Note the mounting pins and bracket on the CSF #8258 are aluminum vs the OE plastic. This offers more stable mounting and durability.

Features

• Sold Individually - all applications 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

Year Range	Make	Chassis Code	Model	Trim	Engine / Trans / Etc	Notes
2019-2021	BMW	F87	M2	Competition	Turbocharged 3.0L L6	-
2020-2021	BMW	F87	M2	CS	Turbocharged 3.0L L6	-
2015-2018	BMW	F8X	M3	-	Turbocharged 3.0L L6	-
2015-2020	BMW	F8X	M4	-	Turbocharged 3.0L L6	-
2018-2020	BMW	F8X	M4	CS	Turbocharged 3.0L L6	-
2016	BMW	F8X	M4	GTS	Turbocharged 3.0L L6	-

OEM Part Numbers

• BMW: 17-11-2-284-603
• BMW: 17-11-2-284-604
• BMW: 17 11 2 284 603
• BMW: 17 11 2 284 604
• BMW: 17112284603
• BMW: 17112284604

Warranty

Cooling Systems and Flexibles, Inc. (CSF) warrants CSF’s High-Performance Cooling Systems, under normal use and service, to the original purchaser of the vehicle in which the product was originally installed. For more information and details please visit our Warranty Page

SKU# 8258 Warranty Term: 2 years