What is it?
Over the years we’ve never been completely convinced by the Audi S8. While it’s never lacked for performance, style, luxury or quality, we’ve always found it wanting in other certain areas – not least of ride quality on coarse-surfaced British roads, leading us to the conclusion that your money would be better off spent somewhere else.
This all-new third-generation model attempts to put that perception firmly to rest. And on first acquaintance, it is a big improvement on old, delivering even sharper performance, vastly improved economy, and crucially, on the typically smooth roads near Audi’s Ingolstadt headquarters in Germany, a firm but controlled ride that lifts its overall refinement to levels approaching those of high priced performance models from BMW, Jaguar and Mercedes-Benz.
The big news with Audi’s new flagship performance saloon is the appearance of a new twin turbocharged 4.0-litre V8 direct-injection petrol engine that in a lower state of tune also powers the latest iteration of the S6 and the mechanically identical S7 – all planned to make their world debut at the Frankfurt motor show.
Engineered in a joint program between Audi and Bentley, which also plans to fit it to the Continental GT and GTC early next year, the 90-degree unit is the first recipient of a new cylinder on demand system that automatically shuts down four-cylinders on light throttle loads for added fuel saving.
As fitted to the S8, it delivers 69bhp and 80lb ft more than the old model’s naturally aspirated 5.2-litre V10.
What's it like?
The gains, however, are not only evident on paper. Right from the off, the advanced unit feels more muscular and altogether more responsive.
On light throttle loads in third gear or higher there are no telltale signs apart from a digital read-out within the instrument binnacle that the new engine’s advanced electronic management system has chosen to close down the inlet and exhaust valves of cylinders 2, 3, 5 and 8 in the interests of fuel saving and lower emissions.
The operation of the cylinder deactivation system on the pre-production prototype we drove was absolutely seamless, both from a mechanical and acoustic standpoint. This perception is achieved, in part, by what Audi calls active noise cancellation – a system used to suppress the typical hum and what the German car maker describes as other intrusive acoustic elements of the engine when running in four-cylinder mode.
With added throttle, the delivery is uncannily smooth and extremely linear across a wide range of revs. There’s no discernible turbocharger lag of any kind, just a compelling and boundless seam of energy all the way from the 800rpm idle all the way to the 6500rpm cut-out point. And to top it all off, there’s a lovely deep burble through the exhaust that grows in intensity as you pile the revs on.
In lower gears, a combination of the new engine’s heady torque loading and the latest iteration of Audi’s Torsen four-wheel-drive system provides for rabid straight-line speed, as evidenced by Audi’s official 0-62mph time of just 4.2sec – or 0.9sec faster than the old S8. Considering its relatively small capacity by performance car standards, its in-gear performance is extraordinary.