We put the big twin-turbo V-12 on the dyno.; The dyno melted.
For a cool $183,000 you, too can have the most delightfully overpowered S-Class in the world – the S65 AMG. It has a 6.0-liter, twin-turbocharged 36-valve V-12 that makes, according to Mercedes, 604 hp @ 4800rpm and (are you sitting?) 738 lb-ft of torque in a plateau between 2000 and 4000 rpm.; Holy (@#$*&.
Okay, stop hyperventilating. Yeah, it lays rubber all the way to 60 mph (and beyond, if you’re not careful). But if you ignore the fact that those numbers are so high, you’ll see something interesting – a horsepower peak at 4800 rpm? That’s unusually low.
Even GM’s technology-from-1882 3.8-liter pushrod V-6 makes its peak at a higher rpm – 5200. What this means is that, powerful as AMG’s V-12 is, it doesn’t rev very high.
Mercedes quotes the V-12′s peak torque from as low as 2000 rpm, but therein lies a problem. This motor makes so much power that even in fourth gear, it spun the dyno up so quickly that it didn’t make full boost until 4000 rpm. Real life is no different – the S65 feels like it has the world’s most narrow power band. It’s either ON (with the largest capital letters you can imagine), or off.
I’m not a huge fan of this engine for a few reasons. Firstly, it has that narrow power band. Secondly, it has enormous turbo lag. And mostly, the car can’t handle it. A big Mercedes sedan costing practically as much as 10 Honda Civics should be fluid, smooth, and fast.; On the highway, the S65 is obscenely capable, fast, refined, and wonderful. It is, in my book and without question, the best Autobahn car in the world.
Unfortunately, off the line, and at speeds legal in the US, it’s a lumbering fool.
Picture this: You just dropped $200k on an S65 and get your best buddy in the passenger seat. You want to show him what 600 horsepower can do. Floor the accelerator from rest, and the rear tires chirp. Heads are flung back. ESP immediately kicks in and retards power. Heads fling forward.
ESP gradually lets power back in, pushing you and your buddy firmly against your seatbacks. Then, boost hits. Oh My God does boost hit. The rear tires turn to smoke. Small children become sucked into the intake. Your necks snap as your heads are thrown against the (thankfully soft) headrest. Tire Shredding Bliss. For about a half second.
ESP intervenes, cuts power, and forces a short-shift into second gear. The shift happens so fast that the fan belt squeals. Loudly. Heads fly forward again. Your friend thinks you have a twitchy right foot and your just grenaded its motor.
After the shift, you’re off-boost and at low rpms. Not much happens for a second. Your friend looks at you, and just as he’s about to open his mouth to ask why you let go of the gas pedal (which, of course, is still firmly buried in the carpet), WHAM, boost hits again. His head smacks off the head rest again. Oh, but wait, the S65 AMG breaks traction again, so ESP cuts power for a second, then regains its trust of the tires and lets full boost back on.
From the chiropractor’s office waiting room, your friend calls to tell you that your car is stupidly fast and sounds amazing. But it obviously can’t handle all the power.
Meanwhile, across town, someone is fantasizing about the forthcoming S63 AMG. In his head, he is giving a demonstration to his friend. The normally aspirated V-8 screams to its 7000-plus rpm redline in every gear, torque swelling with revs. It sounds amazing, feels amazing, and ESP kicks in only once – at the launch in first gear. His friend, though doesn’t have to pony up the $20 co-pay for the whiplash-induced chiropractor visit.
Here’s what the S65′s power band looks like. No, the torque and horsepower labels are not reversed – blue is torque, red is power. We had to reconstruct the curve manually because we couldn’t get a reliable rpm signal from the engine, but the numbers are what they are.
I’m not a fan of huge numbers for the sake of huge numbers, but unfortunately that’s what the S65 is. Me?; I’d take an S550 or an S63 any day.