JAGUAR XFR vs. MERCEDES CLS 63 AMG

Autobild Sportscars Nr. 8, August 2009. Author: Stefan Helmreich

While playing out all the strengths of a paragon of German automotive engineering on the Hockenheim racing course, the driver of the Mercedes CLS is getting increasingly nervous by the twin xenons that persistently appear in its back mirror and get closer at every lap. But rather than being the 10-cylinder product of a Bavarian competitor, the chaser is an offspring of Jaguar’s Midland dynamics centre. Quite a surprise: the British back in the high-end saloon league? A Jag challenging an AMG? Somebody must have let in quite a lot of fresh air in Coventry.

While the predecessor, the S-Type, looked as if it had been styled by pipe smokers in lounge chairs, the XF succeeded in shaking off the narrow corset of understatement. Firstly in terms of its visual appearance, which is characterised by an offensive stance seen on no other Jaguar saloon before. And secondly in terms of its engineering, which marks a turning away from the misbelief that a charger-inflated PS figure would suffice for fixing the R badge. It is still an Eaton charger that produces most of the 510 PS of the extensively revised 5-liter direct injection unit. But while in past R models the sudden torque wave produced smoking tyres instead of maximum propulsion, in the new XFR an electronic central-differential lock distributes the torque in a fully variable manner to the rear wheels. In practical cornering this means that the standard diff lock controls the 625 Nm torque in order to distribute it, according to the DSC mode and throttle position, to the 285-type Dunlops in a gentle, intensive or overwhelming manner.

In principle the CLS can do the same trick. But, on top of boosting the massive basic price of 108,000 Euro by another 2975 Euro, the AMG diff lock directs no more than 40 per cent of torque to the rear wheel in need. That’s irrelevant in everyday driving, though, since at a faster pace the 630 Nm simply seem to overrun the locking action then to get clumsily entangled in the web of electronics. This drawback can’t be fully compensated even by disabling the ESP. Although this gives the CLS tail more leeway, spontaneous lateral drifts with too timid throttle nevertheless often end in an importunately flashing ESP tell tale and gruff brake interventions. The only way to escape such intrusive actions is to keep the throttle fully depressed during the entire drift.

While the Jaguar also features safeguards that prevent drivers from carelessly falling through the electronic safety net, patiently pressing of the DSC button allows unhindered drifting. Anyway the XFR is less willing to compromise and has more bite, while the CLS’s dynamic qualities are significantly hampered by the comfort-biased chassis borrowed from the E-Class.

Although only marginally lighter, the Jag masters the Hockenheim course with much more light-footedness and precision. While a bit light for sporty tastes, the Jag’s steering is accurate and, unlike the spongy AMG solution, provides a positive centre feel. With its adaptive suspension fortunately fully cleansed of any comfort residues in Sports mode, the XFR clearly dissociates itself from the couch-like ride feel of the CLS. Its sometimes rough manners will be forgiven at least by the performance saloon enthusiasts that have felt neglected by Jaguar for so long.

It’s the almost unending Parabolika curve where the AMG tries to fully exploit the 514 PS, 630 Nm and 7200 rpm limit of its power unit, and cast off the annoying chaser. But again the XFR is unimpressed and rises above its reputation. Thanks to its excellent sprinting qualities (0-100 kph in 4.5 s, and 0-200 kph im fabulous 14.7s) the Jag not only pulverises the manufacturer’s figures, but also catches up with the nominally superior CLS by the meter. It’s in the hairpin where the Jaguar XFR strikes the last blow: while the naturally-aspirated AMG struggles to get out of the rpm lowlands by its huge capacity reserves, the Jaguar V8 clenches its broad charger fist and finishes what had begun as a faint foreboding in the back mirror of the CLS, which during the next laps stays as empty as its pilot’s gaze.

VERDICT
1st Place:  Jaguar XFR
A fantastic engine, uncompromising dynamics including electronic differential lock, plus uncensored drifting qualities by the press of a button, at last help the Jaguar to shake off the narrow corset of understatement.

2nd Place: Mercedes CLS 63 AMG
It’s hard to reduce the CLS purely to its performance. But when its quality, comfort and consistently elegant styling are left aside, one must realize that the CLS is no match for the XFR in terms of driving dynamics.

Jaguar XFR
Amazes with radical dynamic qualities and tremendous response.
Cool interior design with plenty of leather and alu, plus “swimming pool” illumination. Excellent, quick-shifting auto box.
Speedo without a trace of megalomania. With the 6-speed box in Sports mode, the current gear is prominently displayed in the centre screen.
The air vents emerge from the fascia when the engine is started.
The long-stroke Jaguar V8 comes with Eaton charger and direct injection.
Split air intakes distinguish the R version from the standard XF.
S/C-marked 20” 7-spoke wheels are standard.

Mercedes CLS 63 AMG
Enjoyable power car with huge thrust but sluggish handling.
Gorgeous cockpit with plenty of wood and lots of extras. The 7-speed auto box has a comfort bias.
Unboosted 8-cylinder with huge capacity, short-stroke cylinder architecture and a 7000+ rev limit.
Only in Sports mode the 7G-Tronics adequately responds to paddle shifter inputs.
The 4 tailpipes produce unrestrained rock music of the finest sort.
Unlike the Jaguar, the CLS comes with 19” wheels only.
The twin-strut radiator proclaims the facelift, and the apron the AMG identity.

Surprise winner? Even though the CLS raises its star narcisstically into the air. it’s the XFR that is shining brighter in the end.



Auto, Motor und Sport Nr. 16, July 16th, 2009. Author: is Götz Leyrer

COMPARISON TEST: JAGUAR XFR VS. BMW M5

R and M are the performance badges of Jaguar and BMW, respectively. M5 and XFR are wolfs in sheep’s (read: saloon’s) clothing. From a 5-litre capacity they produce 500+ PS – the BMW by high rpms, the Jaguar helped by a supercharger.

The 250 kph top speed limit is still kind of a dogma, which even the high-performance departments of major car manufacturers adhere to in their top models that easily could pass the 300 kph mark.

We took two of them to the test. The BMW M5, which with its mighty 10-cylinder engine is the second most powerful production BMW ever, and its young competitor from England that is known by the name of Jaguar XFR. With its all-new V8 engine it also joins the select 500+PS club.

The powerplant demonstrated its full potential on the Bonneville racetrack in Utah, US, where a top speed of just over 360 kph was measured for an XFR that had been subjected to some benign aerodynamic and performance modifications.

On normal roads, and even on the few not speed-limited German motorway sections, the two contestants are equally fast. So marginal are the differences in the test figures, that they cannot help decide which one of the two super saloons offers the most convincing package.

So other criteria are needed. And the different technical concepts offer a good starting point. The BMW comes as a thoroughbred sports car that only lacks a suitable body for perfection. The M GmbH designed a racing-bred V10 in times when 10-cylinder engines were standard in Formula 1. Here life begins beyond the 5000 rpm mark.

The Jaguar XFR uses a V8 that hasn't such explicit sport bias, but was designed for a more universal application. Hence a high-rpm concept of the sort used by BMW was out of the question. Apart from the XF saloon, the Jaguar engine is also powering the XK sports car. And one needn’t be a prophet for seeing the unit in the Range Rover, as well.

Logical consequence: supercharging instead of extreme rpms. Jaguar uses a space-saving charger design which, unlike a twin-turbo layout, could still accommodate front drive shafts when used in Land Rovers. The biggest improvement, though, is that the charger which forms a compact unit with the water-cooled intercooler, causes next to no operating noise thanks to a 4-blade rotor design.

Thus the Jaguar powerplant develops its massive power most discreetly. Its gentleman-like manners only get a bit rough in the top-rpm range when the V8’s full-load fury comes to the fore.

In the absence of any charger lag, the XFR just above idle speed starts to get pushed forward by a torque wave far superior to that of the M5 with the irresistible thrust of a starting jet.

While all the Jaguar driver must do is step on the throttle, the M5 pilot needs to exercise some caution with the high-performance engine: shift down when thrust is needed, revv-up to approx. 8000 rpm, and then shift up. After programming a so-called Launch Control, M5 drivers can achieve marginally better acceleration figures than XFR pilots, and as a special reward enjoy the unique sound of a 10-cylinder.

At high rpms the otherwise humming powerplant develops an aggressive sound composed of intake and exhaust noises, that lets occupants forget that they are sitting in a spacious and comfortable 4-door saloon. In a highly professional manner the M5 plays the role of a car for drivers who see sporty driving as an end in itself, and are ready to admit that they enjoy it.

In everyday life the most important difference between the two powerplants lies in the transmission. The Jaguar comes with a conventional 6-speed torque converter gearbox developed by ZF, which in a similar form is also used by BMW. But not in the M5.

The M-engineers designed a unique automated sequential 7-speed gearbox, but without the latest twin-clutch technology. While it’s been a mere five years since BMW proudly presented this gearbox type, it is already outdated.

While drivers going fast on winding roads will enjoy the responsive and quick shifts, even in such ideal circumstances the inevitable traction interruption upon ratio changes comes as a nuisance. That shifting comfort isn’t a priority is most obvious when road conditions suggest to leave the transmission on its own in D. As an automatic surrogate the M5 gearbox is just a compromise, as the occupants will confirm by friendly nods upon each gear change.

While not of the latest design, either, the Jaguar’s auto box willingly turns into a manual box when the driver wishes to change gears by the wheel-mounted paddle shifters. That’s likely to remain the exception in everyday driving, though, since given the massive torque one mustn’t count oneself among the un-sporty sort of drivers for leaving the shifting to Converter & Co. That transmission responses are so quick and exact is helped by the engine’s willingness to respond to any throttle input in any gear.

While the Jaguar comes as a saloon with sports car performance, spoiling its driver with a smooth ride comfort, the BMW as a sports car in saloon guise offers no such concessions, and passes on all road irregularities to the driver.

In return the M5 in the extreme driving-dynamics tests exhibits its typical advantage, demonstrating by its liberal ESP setup that it is willing to give plenty of leeway to the driver.

Whilst equally safe to drive and handling with the same agility on the slalom course, the Jaguar achieves lower Vmax figures owing to its ESP intervening earlier and more forcefully even in the selectable Sports mode. Even though the Jag’s steering is less sensitive than the BMW’s, it requires less effort in return.

In a comparison test which cannot be limited to the sporty aspects, the comfortable courtesy in which the Jaguar wraps up its high performance earns it a few more points in the final rating. So the British – and the new owner Tata in India – can get the champagne out. At least until the cards are reshuffled. The successor of the M5 is scheduled to be launched in 2011.
   
BMW M5
In the driving tests the M5 achieves genuine sports car results.
The M5 interior comes in excellent quality.
1800 Euro: M-multifunction seat with a host of adjustment possibilities.
Individual programming compromises the M5’s control comfort.
10-cylinder engine: high in revvs, but low in fuel economy.

Jaguar XFR
The S/C V8-engine develops superior torque.
Inspite of the sloping roof the Jaguar offers sufficient headroom for rear-seat occupants.
While less dynamical than the BMW, the Jaguar offers superior ride comfort.
Comfortable, well-contoured seats in the XFR.
Cool Britannia: sober, technical interior. Operation is sometimes complicated.

VERDICT
1st Place: Jaguar XFR
Even in its most powerful variant the XFR has remained a typical Jaguar: it combines the high output of its S/C engine with a comfort that allows relaxed and pleasant cruising. This is also helped by its well-matched automatic gearbox.

2nd Place: BMW M5
The M5 is all about sporty high performance. Its character is shaped by the growling, high-revving 10-cylinder as much as by the uncomfortable suspension that’s tuned for optimum driving dynamics, and by the sequential manual gearbox.

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