Engines on test: Audi 4.0-liter V8 TDI

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Audi’s SQ7 is, without doubt, one of the most inappropriate cars to admit loving, but you can’t help but feel enamoured with the huge SUV. It even has an oddly charming handsomeness to it. It won’t win any awards from those who look at any automobile and see the end of the world. If, however, you are somewhat saner, then it is truly something magnificent to behold.

Powering the SQ7 is the all-new 4.0 V8 TDI, which has been developed to slot in to the big ‘sporting’ Audi SUV, and Bentley’s opulent Bentayga; the latter we tested in W12 format earlier this year. Its application in the Audi is all about performance; a link Audi strangely failed to promote during its dominant WEC years, but one that still packs a pertinent punch.

Despite its SUV surroundings, the SQ7 certainly makes its sporting intentions known early; burbling in to life with vigour once the start button is pressed. It’s a simulated sound; the note emitted outside is distinctly different, more diesel, but this is one of the times that electronic synthesis of sound works. And it works well.

The hot-vee configuration of the engine, in conjunction with its 48V assisted ‘EPC’ third ‘turbocharger’ serve up performance that belies the cars sizeable dimensions; 900Nm of torque available from just 3,250rpm ensure that the Audi stands up to the additional ‘S’ in its nameplate. The 90° V8 houses two variable-geometry, sequential twin-scroll turbochargers, which produce the bulk of the power. The auxiliary 48V system provides up to 13kW to spin the 7kW EPC up to its operating speed of 70,000rpm in just 250ms. Audi states that this eliminates any traditional forms of turbo ‘lag’ associated with larger turbos and the move toward electrification of components will result in more and more traditionally hydraulic systems being supplemented by electricity.

Sadly though, for all of the talk, yet again, of instantaneous throttle response, the SQ7 comes complete with a sizeable dead zone at the top of the pedal travel that once you pass through, erupts with vigour – making low speed manoeuvring tricky. An annoying trait in any car, but one worth over GB£80,000 and the size of a studio apartment is, again, downright terrifying in close confides.

Out on the open road though, and the SUV’s dimensions melt away as the deep resonating burble, hilarious torque burble and driver focused dial cluster trick your mind in to thinking you are in a much smaller, more responsive and lithe car.

As diesel is chastised publically by anyone tenuously linked to the automotive industry, it is a shame to think that cars and engines like this combination may not exist in a little over (or under, depending on how negative you’re feeling) a decade; particularly when they do so many things exceptionally well.

There is also a prang of sympathy for manufacturers that have invested so much money has been invested in their development. However, when the pandemonium is the result of deliberate cheating, it really is hard to feel too sympathetic for the manufacturer at the root of all of these problems…

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About Author

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Dean has been with UKi Media & Events for over a decade, having previously cut his journalistic teeth writing and editing for various automotive and engineering titles. He combines extensive knowledge of all things automotive with a passion for driving, and experience testing countless new vehicles, engines and technologies around the world. As well as his role as editor-in-chief across a range of UKi's media titles, he is also co-chair of the judging panel of the International Engine of the Year Awards.

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