German cars are believed to be impossibly complicated and tricky to work on. But while they might have a few extra screws holding the parts in place, it's basic mechanics at the end of the day. One interesting project that's sure to make headlines in coming weeks is this old 2001 Audi S4 quattro that's been fitted with a limited slip differential and can now do the cool sideways stuff really well.
The diff came from a Porsche, a really old one at that. You might remember the 944 Turbo as a child of the 80s, built until 1988, when it was replaced by the Turbo S. Power came from a then respectable turbocharged and intercooled version of the regular model's engine, pumping out 220 PS. The models that came with a manual gearbox had a high-friction clutch disc setup and also featured a limited slip diff with a 40% lockup setting.
When the 2001 S4 left the factory it did so with a 2.7-liter turbo V6 pumping out 265 PS and 400 Nm (295 lb-ft) for a 0 to 100 km/h time of 5.7 seconds. That was fast back in the day, but thanks to the VAST Tuning Stage III kit, this machine puts out closer to 400 PS nowadays.
Right after the Torsen central differential splits power between the axles, the LSD that's been integrated into the rear transfer case helps keep everything in check and ensures the all-wheel drive S4 can get beautifully sideways.
Why use a limited slip differential? Consider a situation when one wheel is on surface with good traction and the other on a wet or icy patch. The natural tendency of the power is to travel on the path of least resistance, causing massive wheel slip. This is not only dangerous, but also reduces performance. The LSD equally usefull on dry tarmac once you get sideways, with the aforementioned explanation also standing here.
Mihnea's favorite cars have already been built, the so-called modern classics from the '80s and '90s. He also loves local car culture from all over the world, so don't be surprised to see him getting excited about weird Japanese imports, low-rider VWs out of Germany, replicas from Russia or LS swaps down in Florida. Full profile
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