It’s quite likely that many of those who ride in a Bentley Bentayga Diesel will never know that this SUV is diesel-fuelled. You barely hear the V8 at idle and revving it in neutral produces little additional noise beyond a (very) distant crescendo of satin drumbeats.
Engage the eight-speed automatic gearbox and the rev counter needle mostly shuffles around the lower portion of the dial. Even in Sport, it’s rare that you’ll be conscious of the V8 unless you’re working it hard, in which case upshifts can occur as the needle closes on the 5000rpm limit. At this crank speed, the V8 remains smooth, issuing a light V8 beat that could almost be taken for a petrol signature.
So for aural refinement, Bentley appears to have it cracked, even in this prototype. The V8 doesn’t respond quite as urgently as that of the Audi SQ7, the engines being quite differently calibrated despite sharing the same hardware. Aboard the Audi, the throttle response in Sport can be almost joltingly sudden, whereas the diesel Bentayga is pleasingly progressive.