BMW M3 Brake Ducting

by Jerry Skene


After a few years of living with overheating brakes on my 1995 M3, I decided to do something about it. Here you will find several photos illustrating my solution to this problem. Materials consist mainly of aluminum sheet, tube and grill, adapted from their intended use as rain gutters. Total cost including about $50 for the high temperature brake hose came to under $90.


To the undiscerning eye, there is no outward appearance of any changes.

Click here for Front Views of the Completed Duct

To build the duct, I removed the fog lights, and built a tapered aluminum box that fits in behind the fog light opening, the existing brake duct opening, and extends right to the middle of the lower front grill. This increases the duct opening from 76 square cm. to 470 square cm., or a bit more than 6 times. A flexible 2.5 inch diameter tube exits the rear of the box and is routed to the inner hub of each wheel, forcing air into the inside of the rotor.

This seems to work very well, as I haven't had any brake fade, let alone warped rortors, since I have installed the duct.

The process I used to fabricate these ducts is as follows: