► New ‘Whisper’ diesel engine tested
► Replaces the old 163bhp 2.0-litre diesel
► Quieter, smoother, cleaner, faster
This is the new Vauxhall Insignia 2.0 CDTi. To be a little more precise, the car isn’t new but the engine is: it’s Vauxhall’s latest 2.0-litre, 168bhp ‘Whisper’ diesel unit, so called because it aims to exist on a far more soothing, less clattery plane than the fleet-favourite 2.0 CDTi 163 engine it replaces.
What’s so significant about the Whisper diesel engine?
It’s an almost totally new engine compared with the old 2.0-litre diesel unit it succeeds, and one that’s vital for the company car habitat the Insignia inhabits.
Massimiliano Sala, Opel/Vauxhall’s global assistant chief engineer for diesel engines, talked us through the new engine’s highlights, which include an aluminium cylinder head and a plastic manifold, both of which help to dampen noise considerably, and a new balancer shaft to smooth things over.
Apart from being quieter and smoother, the Whisper engine has the more prosaic function of meeting stricter Euro 6 emissions regs. It’ll need topping up with AdBlue solution at intervals, but the trade-off is a reduction in nitrous oxide emissions.
Sala says a key goal from the outset was to avoid losing responsiveness at low revs and with a new electrical actuator for the turbo, boost builds far quicker than the old Euro 5 engine, and revs likewise. Vauxhall claims the Whisper engine offers 4% more power and 14% more torque than its predecessor yet with a massive reduction in engine noise of more than 80%, particularly in terms of secondary rattles and clatters.
That’s partly a ringing endorsement of how quiet the new engine is, and partly a damning indictment of how noisy the old derv was…
So, just how quiet is the new Vauxhall Insignia diesel?
Fire it up and it sounds no more or less muted than most diesels, but once you’re away it really is genuinely hushed, and impressively so. Tyre noise far outweighs engine noise at a medium-speed cruise, and not because the former is at all excessive. The torque spread’s broad enough to make progress easy, and low revs are a pleasingly lag-free zone.
The rest of the car’s perfectly decent to drive, too. Steering response is nice and linear, and both primary and secondary ride quality are both very good indeed. As before, the post-2013 facelift Insignia’s an undramatic but classily competent and relaxing driving experience.
We tested the car in Techline trim. That’s the one aimed straight at company car drivers, so it comes with all the bits a self-respecting rep would need and not much else. So that’s sat-nav, cruise control, Bluetooth and DAB radio, with the bonus of automatic lights and wipers and a bit of extra chrome to make it look a bit smarter in the company car park. Interior plastics are built with robustness rather than plushness in mind, but the cabin’s a comfortable, agreeable enough place to rack up miles.
Verdict
Incremental improvements over its lifecycle have seen the Vauxhall Insignia turn into a quietly very good car. Still not a particularly alluring one, granted, but it ticks plenty of boxes, not least of which is value. And a quieter, smoother, cleaner diesel engine gives it a stronger stance to punch from as the current generation reaches the twilight years of its lifecycle.