9

In theory at least, we’re at best grudgingly accepting the current trend of swapping large capacity normally aspirated engines for smaller units using turbos to make up the difference.

True fuel consumption and emissions can be improved this way, but at what cost? The first victims are usually the throttle response and noise.

But not this time. AMG is in the process of replacing its much loved 6.2-litre V8 with a 5.5-litre direct injection ‘biturbo’ motor. It’s first been fitted to the facelifted CL-coupé, which not only uses a staggering 38 percent less fuel, but has an extra 16 horses to prod the total up to 536bhp and a whacking 125lb ft more torque.

Impressive but not that difficult to predict. What these numbers don’t prepare you for is the ground-trembling thunder, and that’s just when you start the thing up.

Large turbo engines aren’t meant to sound like this. Nor are they meant to respond to the throttle like the CL 63, either. The secret would seem to be not more turbo pressure, but less. Because the engine is still large, Mercedes can afford to blow only moderate amounts of boost through it, which means the engine can run a compression ratio of 10.0:1, a number you’d normally associate with a normally aspirated car.

So there’s no off-boost lethargy at all, or any sudden uncontrollable bang in the back when it kicks in. Any revs in any gear and the thing just flies.

In fact, its character and sound is more akin to the old 5.5-litre supercharged motor AMG used before the 6.2, only with much more shove. We loved that old engine, and anyone who buys any of the AMG products this engine filters into are going to love it too.

As for the CL, the new motor with its solid wall of torque from 2000rpm has transformed it. It now feels epically, heroically quick. It’s still large and heavy but handles its bulk remarkably well, even in very tricky conditions.

All we’d quibble about is the firm ride, even in comfort mode and the fact that you don’t really want to see an interior littered with quite so many parts from lesser Mercs. At £111,985, you’ve earned the right to a bespoke cabin.

Then again, with one twitch of your foot and one bellow from that engine and you’re likely to forgive it everything. Just imagine what it’s going to be like in a C-Class.

Save money on your car insurance

Compare quotesCompare insurance quotes

First drives

Find an Autocar car review

Driven this week

  • 2017 Range Rover Velar
    First Drive
    23 July 2017
    The Range Rover Velar is the most road-biased car Land Rover has made. So does it still feel like a proper part of the family?
  • Seat Ibiza
    Car review
    21 July 2017
    A model upon which Seat has staked its future, the new Ibiza must now deliver
  • Honda Clarity FCV
    Car review
    21 July 2017
    Honda’s fuel cell flagship reaches its second generation, but is the world ready?
  • Nissan Qashqai 1.5 dCi 110 N-Connecta 2017 review
    First Drive
    20 July 2017
    A UK drive in Nissan’s crucial crossover shows an update has not cost it any of that which makes it sell so well
  • Seat Ibiza 1.0 MPI
    First Drive
    20 July 2017
    The Seat Ibiza has wowed in other iterations, but how will the entry-level 1.0-litre MPI version stack up in the UK? We've been to north Wales to find out