There’s plenty of science at the heart of Audi’s new go-faster SQ7 TDI, but when out on a twisty stretch of road it’s still base level emotions brought on by the sheer ferocity of acceleration that count for so much.
We’re traversing some interesting mountain roads through the Parc Naturel Régional des Ballons des Vosges, near Guebwiller in the Alsace region of France which borders Germany’s Rhineland. Summer is on the way, but there is permanent evidence of winter in these parts in the shape of tall snow markers that crowd the sides of the sinewy summit road (we even managed to find some snow, albeit late-Spring slush).
The S version of Audi’s hero SUV model features a new 4.0-litre biturbo V8 which also happens to be the most powerful turbo diesel in a premium SUV; 320kW and a colossal 900Nm of torque. The real story here though is that – thanks to Audi’s first ever twin turbo set-up bolstered by an electric powered compressor (EPC) – all 900 of those Newton Metres are available from the car’s 1000rpm baseline.
Instead of a turbine wheel, the compressor features a compact electric motor. This accelerates the engine’s compressor wheel up to 70,000rpm in less than 250 milliseconds, complimenting the turbos at low engine speeds.
The result? Instant acceleration with zero turbo lag. Remember this is a big seven seater SUV that measures in at over five metres long and tips the scales at 2.2 ton, so a 4.8 second to 100/km from standstill is no mean feat. What’s more, up in the mid-range where overtaking power is always appreciated, the SQ7 still surges forward without any hesitation. This is one quick car.
Another first for Audi, the SQ7 features a 48 volt electrical subsystem which stores energy in a compact lithium-ion battery and manages the EPC and the vehicle’s other driver assist systems, such as the electromechanical roll stabilisation and semi-autonomous traffic jam assists systems.
A DC/DC converter connects the 48 volt subsystem to the car’s standard 12 volt electrical system (which still runs things like the entertainment system, headlights and so on). It’s a clever and efficient use of energy… a bit like getting from A to B across a mountain pass in this thing.
We’ll take an in-depth look at the new Audi SQ7 TDI and its driver assist systems soon.