Another manic Merc? So how many squillion horsepower does this one have?
It’s not the car that’s important, more what’s changed under the bonnet. This is our first taste of a road car powered by AMG’s new naturally aspirated 6.3-litre V8. It’s the company’s first ever ground up engine (the others having all been based on existing Benz motors) and it’ll find its way under the bonnet of almost every high performance Merc in the next couple of years as the old supercharged V8 is phased out.
Who said there was anything wrong with the old engine? It was hardly short on grunt was it?
True, there was nothing wrong with that engine’s outright performance, only the manner in which it was delivered. The big flat torque curve made it easy to go fast, but it all felt and sounded a bit linear. And it wasn’t very efficient: just running the supercharger sapped 100bhp. Stop worrying anyway, the project’s been in safe hands of AMG’s Powertrain Director, Bernd Ramler. His last job was designing the engine for the Porsche Carrera GT.
Suddenly I’m not so sad. But surely it can’t produce as much power as the old blown 5.5 V8?
It certainly does, in fact when fitted to the ML63 it develops 503bhp compared to 486bhp for the E55, CLS55 and SL55. There’s not enough room under the CLK’s floor to run a full set of dual exhausts so power dips slightly to 474bhp, although that still makes it 112bhp more powerful than the CLK55 it replaces which used a 362bhp naturally aspirated version of the old V8. The torque stats are even more impressive considering the absence of any form of forced induction: 464lb ft at 5000rpm, with 369lb ft on hand by 2000rpm. The newly enriched CLK hits 62mph in 4.6sec, 0.6sec ahead of the 55.
So many numbers. I feel like I’m on a date with Carol Vordermann. How does it feel ?
Far more characterful and much less like a massive turbodiesel. Comparing it with something like an E55, you can immediately tell that this engine wants to rev and that that’s what you need to do to extract the best from it. It isn’t as weak low down as an M5’s V10 and the rev limiter cuts in at 7200rpm, rather than 8250rpm but there’s a similar sense of pleasure from ringing it out through the gears. And Merc has finally bowed to criticism of its nannying ESP device too and so on the CLK ESP off means exactly that. Except that the traction control stays on. So it’s still not perfect for full-blooded race-track opposite lockery but great for the sort of mild rear-wheel steering in which you might want to indulge on the road. Other welcome changes are the proper wheel-mounted gear-change paddles and a software tweak which means the box no longer changes up at the redline in manual mode without your say-so. Less useful is some kind of preposterous race timer function built into the trip computer, a bit like the one you can have on a Porsche 911.
Speaking of which, wouldn’t I be better off in the Porsche?
We’d take the Porsche every time, it’s so much more the sports car. There’s comedy value in the sheer absurdity of the way this thing accelerates but the 911, with its greater steering precision and body control, satisfies on so many more levels. Unless you really do need a pair of proper back seats, whereupon the CLK begins to make a case. Or you could hold off until the next M3 arrives. It’ll be fast, cost thousands less and still have room for four. And we’d put money on it driving rings round the Merc.
Fair enough, but since this naturally aspirated engine makes 474bhp, just imagine what it could do with the old car’s supercharger bolted on!
You’re on the right lines but think turbocharger instead. There will be two versions, a low-pressure engine developing 570bhp and a taps-fully-open 700bhp monster. C-class-family cars like the CLK, SLK and C-class itself won’t get these blown engines but those based around the E-class will. Tweaking the V8 means Merc can give cars like the CLS the performance of the SL65 without resorting to the expense of shoehorning in the twin-turbo V12.
Verdict
Great engine, average car. The CLK63 is fun in a brutish manner but proves what sometimes gets lost in the tyre smoke: that big power does not automatically make a great car. SLK63? They might be onto something with that though.