Brake performance has always been one of the weak links of the BMW M Cars since the E36, E46 and E90/E92 M3 models came with single piston sliding calipers and heavy one piece discs. Chances are if one takes their M3 to the racetrack and needs significant braking improvement, the only option is to completely upgrade the braking system.
On the new F8X M3 and M4, BMW has upgraded the OE calipers to Monobloc 4 piston front and 2 piston rear units which are significantly better than the previous models. Since the role of the brake discs is to be a thermal heat sink, as they absorb most of the “load” in the braking system, one of the most cost effective brake upgrades one can do for their BMW F8X M3 or M4 to improve disc life and overall performance is to upgrade the OE drilled discs to Alcon Motorsport 2-piece discs.
The OE drilled discs found on the M3 and M4 are designed for maximum comfort, low noise and to be cost effective to the vehicle manufacturer. However, they are not suited for track day or heavy duty use since drilled discs are more prone to fatigue and heat related cracking. Since the new BMW M3 and M4 are considerably faster out of the box (3400 lbs, 425 horsepower) compared to the older BMW M models, and easier to upgrade (raising the boost, changing suspension, swapping to larger tires), the brake discs will be the first to get taxed. Alcon Motorsport discs are slotted instead of drilled and feature a stronger proprietary cast iron blend compared to the OE discs which makes them more suitable for higher demand usage.
This Alcon 2-piece disc assembly upgrade also works with the OE brake system components, needing no additional modifications, which also makes the upgrade very cost effective long term.
One of the main consumable costs involved when running any car aggressively on the street or on the race track is that of the brake components (brake discs, pads, fluids). The current generation BMW M cars are significantly faster and more demanding on brakes compared to the previous model BMW M models (E46, E92, etc…). Running the OEM discs and pads at elevated temperatures (like those found on the racetrack) will almost always result in brake fade, loss of performance, and excessive wear rates of the discs and /or pads.
While it is possible to simply keep spending excessive amounts of money on replacement OE discs, the metallurgy and design of the OE discs are designed for maximum comfort and cost savings to the vehicle manufacturer, not for maximum longevity or performance. Swapping the OE discs to Motorsport grade brake discs, which are designed for use under the most severe braking conditions, will reduce the overall long term costs of brake consumables on the track and improve the overall performance of the brake system.
Multiple BMW teams have relied on Alcon Motorsport discs in professional racing categories such as IMSA, Grand-Am, and Pirelli World Challenge for their longevity, resistance to thermal cracking, and improved performance. The same Alcon Motorsport discs used in professional racing with BMW Motorsport teams such as Fall Line Racing and Turner Motorsport are also used in the Alcon 2-piece disc program.