Do-It-Yourself Ram Air Tube (RAT)
(for aftermarket E36 intake systems)

Since the E36 "brake ducts" don't really do anything to actually cool the brakes, I decided to utilize the driver's side duct to make a ram air tube for my Jim C/Eurosport intake on my 330ti.  It was cheap, simple and took about 15 minutes (mostly taking pictures).  Not sure what gains you actually get, but it's easy to install/remove.

So, here it is, my instructions for your very own RAT (Ram Air Tube).

hose.jpg (19905 bytes)

First, you need an appropriate hose.  I bought this 2-1/2" diameter, 7 ft. shop vac hose from Sears for only $17.99.  I cut about 20 inches from one end to start.

 

remove_filter.jpg (48481 bytes)

Remove the air filter from your intake.

 

hole_cut.jpg (44623 bytes)

Using a Dremel tool, I cut a rough hole in the brake duct.  I trusted myself enough not to remove the brake duct itself, but cut it while installed in the car.

 

hose_installed.jpg (44147 bytes)

Test fit the ram air tube into the hole (may require trimming)

 

hose_in_duct.jpg (21135 bytes)

Feed it through the front of the brake duct.

 

power_booster.jpg (34151 bytes)

I found this optional power booster, and it seems quite effective.  Unfortunately, I haven't figured out a way of mounting it while drive the car yet.  :-)