Dyno-Testing The Monster From Planet Torque

"Hello, Mr. Viper? Yes, fine, thanks. Listen, I'd like to introduce you to a friend of mine. He's a large fellow. Has expensive tastes. Very soft-spoken. Dignified, even. But don't let his looks fool you. This guy packs an uppercut that would clean your clock."

Yes, the engine boldly emblazoned on the breastplate above makes a Viper's V10 seem lacking in dangly bits. It's simply the torquey-est engine in a stock production car we've ever tested, and it's across the jump.

"Production car" is an imprecise expression, as the 2011 Bentley Mulsanne is hardly a car the average Joe will see twice in a year unless said Joe works in a Bentley dealership, in which case he's no longer average and the statement holds.

Still, this is a car subject to all regulatory requirements of emissions and noise and the like, and was developed by an OEM to meet OEM levels of driveability and durability, no different from a Viper or a Honda Civic. The Mulsanne isn't some tuner special. Not that anyone would mistake it for one.

In the past, Bentley nee Rolls Royce engineers refused to quantify the output of their engines, preferring instead the understatement that the sauce they dished up was "adequate."

Nowadays the crew in Crewe (or wherever) don't shy away from hard numbers, and they peg the Mulsanne's bent-eight at 505 hp and 752 lb-ft of torque.

Here's a better visual of the Mulsanne's adequacy:

That's 676 lb-ft of torque at 2550 rpm, as measured at the wheels by a Dynojet chassis dyno. The engine effortlessly whooshed this out as if it were doing nothing more than smearing a pat of butter on a crumpet. Insanity. This is what you get when you force-feed a 6.8-liter -- beg pardon, it's a 6 3/4 litre -- pushrod V8 with twin turbochargers and two liquid-to-air intercoolers. It's also got variable cam timing.

In light of that description, its observed peak power of 474 hp at 4150 rpm at the wheels isn't much to write home about. Bentleys have never been about peak power numbers; their calling card's always been torque. 

Which makes the Mulsanne's 8-speed autobox a total head-scratcher. Yeah, the gearchanges are so smooth you could wipe a sleeping baby's ass with them, but there's so much torque at play that this thing could have a 3-speed transmission and nobody would ever notice. Or care. 

The transmission also made this car nearly dyno-proof. It has a manual mode, but it 'times out' if you don't command a gearchange a few seconds after selecting the mode. 

Beyond that, it wanted to downshift sixteen gears (or so it seemed at the time) if the throttle was cracked open with any kind of aggression. It took a hell of a lot of aborted attempts before we were able to confuse it into giving us a clean run from low revs.

Okay, so this well-dressed fellow has the low end of a locomotive, but the Viper V10 is victorious as the revs pile on. To wit:

This is nuts. Who would ever guess there's an engine out there that makes a Viper V10 look peaky and high-strung?