Interior

Road Noise Reduction

My 88 S4 has always had lots of road noise. My first tires were Goodrich Comp T/A's, and now
Dunlop SP8000's. The Dunlops are quieter than the Comp's, but not my much. I suspected that
much of the noise is getting into the cabin via the rear wheel arches, so I deceided to do a bit of
soundproofing. I removed the rear wheel inner fenders, and found that the factory
undercoating is very thin. After carefully cleaning the area of loose road grime, I used four cans
of rubberized undercoating spray per wheel (total of 8 cans), slowly building up a coating of
close to 1/4 inch. I only sprayed the stuff on the metal surfaces that form the wheel arches
inside the cabin, and was careful not to plug up any drains. I just drove it today.. the results are
stunning.. It was really effective and much quieter. I am very pleased, and maybe I can get
even better by getting quieter tires next time. I'm not suggesting it will work for everyone, but it
sure worked for me.

Keep the shiney side up :)

Mike Clemens
88 S4 Granite Green 38K and rising