In the community of European car lovers, who doesn’t love an S6? It’s tastefully understated from outside, tastefully luxurious on the inside, and tastefully overpowered on the road.
Interesting stuff if you’re into this kind of thing. It’s not that uncommon to find that someone has tinkered with an air-cooled engine without being aware of some unusual and subtle requirements. That being the case, you never know what you’re going to find when you go in for a simple valve adjustment, as in this instance.
The engine in this car was originally designed for the C-Coupe from the early 2000s. That was a port-injected, naturally aspirated affair. Now they’ve bolted on a vacuum pump to one cam, a high pressure fuel pump to the other cam, beefed up the timing chain to more than twice its original strength, and put a turbo on it.