Inside the Audi S4.
The B8 S4 (3.0 TFSI supercharged) is one of the more distinctive engines Audi built in the 2010s — a factory Eaton TVS supercharger sitting in the valley of a 3.0-litre V6. It responds superbly to Stage 1 (usually 60–90 hp on 98) but has a specific weak point: the supercharger coupler/clutch. Failure symptoms are often misdiagnosed as throttle body, MAF or ignition — we diagnose properly with ODIS live-data before quoting anything.
The B9 S4 switched to a turbocharged 3.0 TFSI. Different engine entirely, different maintenance profile. ZF 8HP eight-speed automatic on B9 replaces the S tronic dual-clutch of the B8 — needs fluid on interval (80–100k km) regardless of any 'lifetime fluid' claim.
Both generations benefit from proactive carbon cleaning around 80–120k km, and both have coolant/thermostat items worth checking every service. We know these platforms cold — B8 supercharger noise, B9 turbo oil-feed inspection, ZF 8HP fluid service — because they're weekly work.

