Blowing the roof off

David Booth is enthralled by the thunder of the lightning-quick Mercedes McLaren SLR Roadster

Without the roof, the staccato roar of the Mercedes McLaren SLR's 5.5L V8 can be fully enjoyed, but the driver and passenger will still be able to hold a conversation.
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Cars, like people, make lasting first impressions. And just like people, those initial impressions are aural as well as visual. Fire up a Ferrari and the great whooping noise spewing out of its tailpipes speaks to not only an inner speed demon but of an extrovert that would make Paris Hilton blush. Aston's DBS on full chat, on the other hand, may also speak to a equally addictive need for speed, but it's a more sophisticated dance partner, more proficient at, say, the rhumba than swing.

And what of Mercedes-Benz's McLaren SLR? Well, flip the little cover atop the gear lever - totally Top Gun, by the way - mash the hidden starter button and what immediately comes to mind is NASCAR. Yes, the SLR is European by way of England and Germany, but the sound emanating from its four exhausts tips is decidedly American. Indeed, the throaty baritone that emanates from those lovely sidepipes (evoking, oh so successfully, images of Stirling Moss and his famed victory in the last Mille Miglia in the original SLR) is so distinctly Yankee it could be a Le Mans-tuned Corvette if only there was more valve clatter. It's as American as apple pie, six-shooters and the kind of football that requires a helmet and shoulder pads that look like they've been stolen from a bomb disposal expert.

Indeed, every time I throttle the supercharged 5.5L V8, I can't help but conjure up memories of the NFL's most undersung running back, Franco Harris. American football's flesh-and-bone version of a wrecking ball, the famed Pittsburg Steeler didn't so much run past the opponents' defensive line as through them. Every power pulse from the SLR's big engine sounds as concusive as one of the famed Pittsbrug Steeler's bone-crunching runs through scrimmage. It's as if each of those gargantuan eight pistons is determined to spin those huge 295/30ZR19 rear tires all by their own self. If a Ferrari at full chat sounds like it's about to defy the laws of physics, then the McLaren sounds like it wants to pound them into submission.

That aural delight is made all the more apparent in this, the roadster version of Mercedes' super-est of cars. With no roof to insulate and its trademark sidepipes poking out just aft of the front wheels, passengers are front row and centre in the concert hall that is the SLR McLaren. Depending on your level of devotion to the combustion of fossil fuels, this can be either Wagner at his finest or the Beastie boys in their worst scratch-and-scream phase; the one common denominator is that, ensconced in all that iconic red and black leather, you will not be ignoring that big thundering herd of horsepower ahead of you.

Of course, if the supercharged V8 is making big noise, it's also making big horsepower; 617 of it when the throttle pedal is matted and the revs climb above six grand. Things start flying by in a big hurry, the SLR pounding its way to 100 kph in just 3.8 seconds. Its top speed, given enough headway and a raft of lawyers to fend off the attentions of the local constabulary, is a whopping 334 kph. I can attest to at least the first 300 of those as that was what the speedometer was reading when my bottle ran out during a test of the coupe version in Spain a few years back.

What's most amazing is that all that power is emanating from a motor based on Mercedes' previous-generation V8. Where AMG's new 6.3L V8 is all variable valve timed with four-valves per cylinder and double overhead camshafts, the SLR makes do with but three valves - two intake and one exhaust - feeding each piston and just a single cam in each head. Mercedes makes up for this relative lack of technology by wicking up the supercharger to 13.05 psi of boost, not quite so much as Audi pumps into its tiny 2.0T, but significant numbers for an engine displacing 5,439 cc.

I did not, unfortunately, get an opportunity to put all of those cubic centimetres to work, nor did I provide much of a test for the SLR's gargantuan 19-inch ZR rated radials. However, having tested the coupe previously this much is certain: the SLR roadster is as stable at speed as the coupe; that is nothing short of a hurricane is going to brush it off path. Likewise, roll is minimal and grip astounding.

However, two significant improvements have been made to the last of the SLRs (coupe production stopped last year). First, the ride is much more supple. Indeed, I can name a host of much more pedestrian AMG products with far harsher suspension. As well, the SLR's steering isn't quite as sensitive as it once was, Mercedes having been able to maintain the tremendous feedback to the driver while not seeming quite so overboosted. Overall, the roadster is an improvement over the coupe version I tested two years ago.

However, despite all its jaw-dropping performance, there actually could have been more. The SLR's limitations - and, yes, I know it's absolutely ridiculous to speak of a car that hits 334 klicks an hour as limited - are its transmission and some latent lardiness compared with some of its competition. Not only is the SLR's trannie an automatic but, unlike more modern Mercedes seven-speed slushboxes, it only sports five forward gears. At the time of SLR's development, it was the only transmission in Benz's stable that could handle the 5.5L's 575 pound-feet of torque. No doubt a more modern gearbox would shave another few ticks off that already impressive acceleration time.

The other limiting factor are the SLR's 1,768 kilograms, hefty numbers by sports car standards. What makes this ironic is that, constructed by Formula One legends McLaren, the underlying chassis is the epitome of futuristic and lightweight engineering. The entire chassis and body aft of the firewall is one gigantic but lightweight carbon fibre tub, while the front suspension and engine frames are almost-as-light aluminum extrusions. According to lore, the problem is that Mercedes added many of its traditional accoutrements and electronic safety devices, raising the SLR's curb weight far above what McLaren originally envisaged.

As much as it may force a performance penalty (again, cue the stupidity of decrying a 3.8 second zero-to-100 acceleration time), there is much benefit as well. The SLR may accelerate like an F-14 on afterburner and corner as if the laws of gravity do not exist, but its interior is (almost) as comfortable and comprehensively appointed as the company's more sedate SL roadster. Indeed, Mercedes aficionados will recognize most of the switchgear and audio componentry in the SLR's dashboard.

That 'almost' qualifier in the previous descriptor of the SLR's comfort is the seats. Finely crafted they may be in carbon fibre, but they offer precious little adjustability. They move fore and aft and there is some slight ability to tilt the entire seat, but you can't, as we back-pain sufferers demand, adjust the seat back for increased rake. Though the driver's seat are available in five different sizes, once chosen you'll live them with for the life of the car and woe be the L4/L5 lumbar that doesn't like the seat angle that McLaren chose.

Enforced seat accommodations aside, though, the SLR is the rational supercar if indeed such a beast exists. Yes, it goes a trillion miles an hour and makes the most delicious of vroom noises, but it will also carry two sets of golf bags in its trunk and it's possible to hold a conversation at 100 kph without shouting one's self horse. Try that in your Porsche Carrera GT. motoring@thenational.ae