Audi RS6 (C8) exhaust sound: 4.0 TFSI twin-turbo V8

Audi RS6: mechanical breakdown

C8 RS6 exhaust note, 19 seconds

A 19-second exhaust clip of a C8 RS6. The caption names no parts and no events. The source of the note is the 4.0-litre twin-turbo V8, which has a deep burble that gets louder with the optional RS sport exhaust.

48-volt system and cylinder deactivation

Two pieces of electronics sit on top of the 4.0 TFSI: a 48-volt mild-hybrid system and cylinder deactivation. The deactivation means the V8 is not always firing all eight cylinders, and the engine control unit is what decides when it drops cylinders and when it brings them back. For the exhaust, that matters because the burble comes from the twin-turbo V8 working as a full eight. With cylinders switched off, the firing pattern behind it changes. The hot-V layout puts both turbochargers inside the V, so the pulses reach the turbines before the exhaust system. Whatever the sport exhaust adds, it receives what the software has already produced.

Stage 1 tune, downpipes and exhaust

The ECU tune comes first. A stage 1 file gives large power and torque gains from the twin-turbo V8, which starts at 592 hp and 800 Nm. The cost is warranty risk and more stress on the gearbox and drivetrain, meaning the 8-speed Tiptronic and quattro hardware. The second change is an aftermarket exhaust or downpipes. That gives a louder V8 and some extra power once a tune is added. The trade-off is emissions compliance and noise limits: downpipes affect the former, a louder system the latter. Owners who want volume without either problem can start with the factory RS sport exhaust, which is already an option.