March 24, 2021 2 min read
Or, what's with the front brake ducts on the M2 CS?
We have been lucky to prepare and procure some special BMW's - and we include the BMW M2 CS in that list. Reviewing BMW's documents we found some notes on the covered, or capped front brake ductwork on the M2 CS.
As others have found, if you follow the brake ductwork starting in the front lower grill and then into the the front wheel well, you'll may see the ducts on each side of the car are capped near the tire. It appears the ducts are included on all of the CS's regardless of the brake package installed. We have seen the caps on both steel and carbon ceramic brake cars, but we can't confirm if this was though the entire production period. This might seem non-standard when looking at past BMW production cars and found the duct work open on both sides - e36 M3's for example.
Other than collecting rocks and other low-lying items, (and making it hard to clean out) why have these in place if the air can't go anywhere?
From BMW's document, we find:
When driving on a race track:
"If installed, remove the covers of the brake ventilation ducts in the front section of the front wheel arch covers and keep them in a safe place.
• M2 (F87),(emphasis added) only in case of equipment specification with carbon ceramic brake
• M3 (G80), for all brake systems
• M4 (G82, G83), for all brake systems
• M5 (F10, F90), only in case of equipment specification with carbon ceramic brake
• M6 (F06, F12, F13), only in case of equipment specification with carbon ceramic brake
• M8 (F91, F92, F93), only in case of equipment specification with carbon ceramic brake
In order to improve the cooling of the brake system, the covers of the brake ventilation ducts must be removed before driving on the race track.
The covers of the brake ventilation ducts must be reinstalled before driving on public streets. "
Presumably this could explain why some online "test" drivers who demo'ed the car with ceramic brakes had some heat related issues.
It is important to reinstall the covers after being on track - the road debris and rocks entering the area of the ceramic rotors could impact the brake system and possibly cause chipping or other issues.
*While there are many factors involved in deciding to run a car with the carbon ceramic brake package on the track, we provide the following information as we haven't seen this publicized, and feel this may be of help for those wanting to track their cars.