S4 Exhaust
Posted: Mon Nov 17, 2003 10:18 am
Have just picked up my new (ish) ex demo S4 Avant from Poole Audi, (great service), 6,000 miles Nogaro, alcantara and Bose. Looking underneath the back I see that the tail pipes are siamezed together and one each side has what looks to be a vacuum operated divertor valve. Anyone any ideas why? Is it to keep the noise down at low revs, does the engine need back pressure? Very please with it but may need to visit AMD!