Air Dam/Splitter
1990 928 S4

June 16, 2007

After the 2006 Open Road Racing season I decided I needed to modify the
aerodynamics of the car to reach 200 mph. I contacted Marc Thomas at DEVEK
to install an air dam/splitter, like the one on The White Car. The air dam was
designed for their 1988 928, but needed to modified to fit my 1990, with it's oil
cooler mounted under the radiator.

Here is the car with the new air dam at the 2007 Bonneville 100 in full race trim:

Update August 16, 2013:

I just made a new skirt (air dam) for the air dam/splitter. I need to do this after each
race as the road tends to scrape and wear away pieces of the plastic. The skirt is made of
lawn edging material, cut to length and holes punched at the proper locations. The skirt is
held in place by an aluminum strip and zloc fasteners.

Under the plastic air dam is the steel splitter and mounting frame. This part takes
a beating and has had to be straightened many times.

The back of the steel splitter attaches to the aluminum belly pan and provides protection
for the engine. I added some extra steel plate to add extra protection, and it's worked:

Here is a final shot to show the amount of overhang:

As a testimony to this air dam, all three 928s that have exceeded 200 mph in ORR were
using this design.

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Copyright 2007, George A Suennen
written: 06/16/07
rev: 08/16/13