[MetalMK]

Recently I found a plastic cap inside both the front wheel arches. Removing them exposes some kind of duct that goes from the front bumper to the front brake rotors. Seems like brake cooling ducts to me. I want to remove them to cool my brakes better, but I wonder why BMW would block them. Has anyone removed them before?

[overcoil]

This is an extreme case but some inlets aren’t as efficient at cooling unless you use a duct into the disc shield to direct air flow directly onto the disc.

U could conceivably just be adding more under fender turbulence. And u probably don’t need much more cooling. And if u open the duct it may NOT effect braking negatively.

[MetalMK]

Originally Posted by ScottSinger

This is an extreme case but some inlets aren’t as efficient at cooling unless you use a duct into the disc shield to direct air flow directly onto the disc.

U could conceivably just be adding more under fender turbulence. And u probably don’t need much more cooling. And if u open the duct it may NOT effect braking negatively.

I guess I should keep them closed? But what is the point of putting that duct there?

[overcoil]

Originally Posted by MetalMK

I guess I should keep them closed? But what is the point of putting that duct there?

German market autobahn

modifying the car for racing

assembly access cutout


I’d confirm it’s a performance upgrade before opening.

[RoundelM3]

I opened the ones on the wife's 228i convertible and blew out a pound or so of leaves and debris that had accumulated. No ill effects that I can discern after a year of having them open.

[Tpeterson]

Originally Posted by MetalMK

Recently I found a plastic cap inside both the front wheel arches. Removing them exposes some kind of duct that goes from the front bumper to the front brake rotors. Seems like brake cooling ducts to me. I want to remove them to cool my brakes better, but I wonder why BMW would block them. Has anyone removed them before?

Mine were never closed. 2015 228i. I also assume they're brake cooling ducts.I have the Brembo brakes from the THP. Do you?

[overcoil]

Btw 2015 235 mine are also open.
Can’t imagine having any negative effects - am wondering why some would have them blocked off.

[pikcachu]

Originally Posted by ScottSinger

Btw 2015 235 mine are also open.
Can’t imagine having any negative effects - am wondering why some would have them blocked off.

they are open for hot climate regions and closed otherwise

[ianp622]

Keep in mind there's always a trade-off between cooling and drag. It's likely closed because in the conditions the car was built for it didn't need it.

[mayday813]

The brake cooling ducts are open on my 2017 M240 xdrive and on my wife's 2015 335 xdrive sportline.

[Maynard]

I think that they are blocked to provide the 'air curtain' and open for performance options, may also affect brake dust or where it lands. RealOEM manual shows brake ducts leading back to them. Mine were closed but I've opened them for the summer track season. I think this helps braking and frees up almost as much hp as putting on an ///M badge

[Cumberlandjames]

Originally Posted by MetalMK

I guess I should keep them closed? But what is the point of putting that duct there?

I have had them removed from my M235 for a couple of years now. It is impossible to measure the amount of added cooling without instrumentation but I can verify that the amount of brake dust accumulation is significant which would definitely indicate an increase in airflow over the brake and wheels.

I don't drive mine n the winter but if you intend to, I would put the covers back on to reduce the amount of snow, slush and salt channeled at the wheel well.

Take them off and store them until they are needed.