The Jaguar XKR 75


The XKR 75 Story

by Ross Barkman

The XKR 75 Goodwood Limited Edition was Jaguar’s 75th birthday present to itself and its customers – a ‘tougher’ version of the XKR with the emphasis on performance and handling.  But what exactly is it, and how did it come about?  Jaguar kindly arranged for me to speak to Dave Pook, one of the dynamics team that worked with Mike Cross, Chief Engineer, Vehicle Integrity at JLR, on the development.

The genesis dates back to 2006, before the introduction of the X150 4.2 XKR.  Mike, Dave and Matt O’Hara completed the XKR development, but still had the test vehicle; they decided it would be interesting to see how the car would be with a bit more driver-focussed development.  Jaguar management told them they could carry on, but it would have to be in their own time – this flexibility to allow the use of company facilities to develop pet projects is something I’ve always admired in Jaguar (shades of the XJ220 again!).  A lot of unpaid evening and weekend development work eventually led to the 2008 4.2 XKR-S, a 200-unit limited edition, with stiffened and lowered suspension, an aero bodykit, forged Vortex alloys and a top speed of 174 mph.

But they didn’t stop there.  While the development of the 5.0 XKR was underway, the same trio, along with Jon Croxford, Michelle O’Connor, Dave Moore and assistance from a few others, was working on a similar out-of-hours upgrade of the new car. With the new XKR’s more powerful engine and active differential, they were already a jump beyond the 4.2 package.  Taking the same principles used on the 2008 car and starting with many of the same components (springs, dampers, forged wheels), they added revised steering, software tweaks and more power to the mix, with a new exhaust and a revised ECU map.  The original incarnation appeared as the “Goodwood Special” in lurid lime green at the 2009 Festival of Speed.

Come 2010, and it was Jaguar’s 75th anniversary.  The Jag bosses, already impressed by the Goodwood Special, were persuaded to release a production version as a celebration model.  Only 75 were made, sold in the UK, Germany, France, Italy, The Netherlands and Belgium – and only 20 of these were right-hand drive for the UK market.  Unsurprisingly, they dropped the Kermit look, and all cars were kitted out in dark Stratus Grey with Charcoal leather and Piano Black veneer.  Pale grey ‘mascara’ stripes over the wheel arches were, fortunately, an optional extra.  A different 175-unit limited edition, the XKR 175, was released in the US and Canada, but this was basically a Speed Pack model without any further performance/handling modifications.

 

The full “XKR 75 Goodwood LE” spec, and its relation to the later Dynamic Pack and XKR-S, is as follows:

·         Power increased to 530PS (523bhp) from 510PS (503bhp) on the XKR, and torque increased to 655Nm (483ft-lb) from 625Nm (461ft-lb).  This was achieved both through exhaust changes and recalibration of the engine ECU, the latter in partnership with the Rocket Sports Racing engineering team that worked with Jaguar on their 2010 motorsports programme.Off-the-record comments from Jaguar, mentioned in reviews published at the time, hint that the actual outputs are nearer 540bhp and 515ft-lb.

·         ‘Sports exhaust’ with improved performance and acoustics, removing the centre silencer boxes and replacing them with a crossover pipe, but retaining the rear boxes and outlets. A later refinement with larger outboard exhaust outlets became the Performance Active Exhaust, an XKR option and standard on the XKR-S.

·         Upgraded torque converter to handle the increased torque (carried over to the R-S).

·         Electronic speed limiter increased to 174 mph (280 km/h), and 0-60 time decreased to 4.4s, 0-100 to 8.9s.  However, I’ve discovered that, on my car at least, the limiter seems to have been set at 186 mph (300 km/h), the same as the R-S.

·         Re-tuned Adaptive Dynamics damper-control software,increased spring and damper rates (front springs 28% stiffer, rear springs 32%) and lower ride height (10mm).  Active Dynamics was further tuned for the Dynamic Pack and R-S, but the springs and dampers are the same.

·         New fully machined aluminium front and revised rear suspension uprights that increase camber stiffness by 30% – the former is unique to the 75, as the R-S and Dynamic Pack (being larger production runs) have a cast front upright with the same design.

·         Speed Pack body kit with body-coloured finish: front splitter, side-sill extensions, rear diffuser and larger rear spoiler.  This reduces lift by 25%.  All of the exterior trim is also body-coloured or black.

 

·         20″ Vortex forged lightweight alloy wheels, diamond-turned with dark grey finish, 9” front and 10.5” rear, with rear tyre width increased by 10mm to 295mm.  The forged wheels reduce unspring weight by approx. 4.8kg. While the fronts are the same as the 2008 XKR-S, the rear wheels have a larger offset because the rear axle is different from the 4.2 XKR.

·         Other goodies: XKR 75 sill tread plate, active front lighting, DAB radio, red brake callipers, commemorative card signed by Mike Cross and Ian Callum, optional graphics pack.

·         Although publicity at the time implied that there were revisions to the Electronic Active Differential software, the team ran out of time and budget and the standard XKR settings were used. That was rectified in the XKR-S, which received a custom version of the EAD and Dynamic Stability Control software.

 

The success of the 75 showed that there was a market for a ‘harder’ XKR, and the team was given full company funding to develop the concept even further.  The result was the XKR-S, with changes to the active diff., dynamic stability control and adaptive dynamics, as well as a revised body kit that reduced lift by 26% (1% more than the Speed Pack),a top-speed increase to 186 mph, and sports seats.  Dave Pook has carried this work forward to the R-S GT which he describes as “slightly bonkers”.

In effect, therefore, the XKR 75 is what evolved into the Dynamic Pack (including the Speed Pack) and the Performance Active Exhaust, with the addition of engine power/torque enhancements and a stronger torque converter to handle those.  It is a sort of halfway house between a fully performance-optioned XKR and the XKR-S.

So, how did I come to own an XKR 75?  My policy is: buy a good-quality, low-mileage second-hand car every 10 years – I get to have a really nice toy, the quality means it lasts the distance, and over that period of ownership, it costs about the same as buying a ‘normal’ car every 3 years or so like my colleagues do.  I bought my first Jag in 1989 – a black ’87 XJS V12.  In 2000, I replaced it with an anthracite ’97 XK8.

My XK8 was due for replacement three years ago, but the economic situation was taking lumps out of my savings and the car was running well, so I waited.  I began to wonder: did I want to move on to the obvious replacement, a 5.0 XK or XKR, or should I consider something a little more exclusive like an Aston, or the true supercar performance of a Nissan GT-R?

I realised I’d need to go for an older Aston to fit my £40k budget, and my servicing costs would increase.  I test-drove several GT-Rs – the performance was phenomenal, but in normal city driving the ride was hard (even in ‘comfort’ mode).  The cars had a clunky, mechanical feel compared to the XKRs I drove, and the run-flat tyres tramlined horribly.  So, a great track car, but not so pleasant for normal driving.

In the end, I came back to the XKR 5.0, and was looking for a Black Pack plus Speed Pack model when I stumbled upon an XKR 75.  I liked the spec, I liked the look (they had removed the mascara stripes) and I liked the exclusivity. I contacted the dealer, and after a haggle on price, we had a deal.

On the road, the 75 is noticeably firmer than a standard XKR, but it hasn’t lost the classic Jag compliance; it’s certainly much more comfortable than the Nissan GT-R.  The suspension changes make the steering very direct – you point, it goes.  It understeers on the limit, because it’s a heavy car, but you have to push it very hard to find that limit.  The car feels very well planted, particularly in Dynamic mode, and the handling is sharper than a standard XKR (based on my limited experience of the later).

The torque is massive, and it far exceeds the rear tyres’ ability to deliver it to the road.  You have to learn to feed the power in off the line, or the DSC traction control steps in and you proceed in a series of surges as DSC cuts in and out.  Of course, you can switch to Trac DSC or even turn DSC off, but then you’ll leave long black lines and may still not accelerate any quicker, or you’ll experience some very tail-happy moments.

The exhaust sound is glorious.  When idling, it sounds like a dragon gargling; if you give the throttle a good shove in neutral, there’s a wicked crackle on the overrun; when you give it the beans while moving, there’s a mighty roar.  This car can be loud.

Around town, on dual carriageways or motorway, there’s really not a lot of advantage over the standard XKR.  It’s different on an autobahn, where the much higher speed cap does allow you to just blast past slower traffic when a gap opens up.  No-one passed me on my non-restricted autobahn travels; a 911 Carrera 4S (not the latest, probably a 997) came out to play, but couldn’t keep up.

However, it’s on two-lane A- & B-roads with twists, turns and short straights that it really comes into its own.  In Sport mode, the throttle response is immediate and massive – you find yourself past the two cars in front before you’ve even thought about it, and you suddenly realise that the other two further ahead are still within safe reach. And, of course, it’s playing our favourite V8 tune as it goes…

On the track, the car achieved an 8:01 Nürburgring Nordschleife lap time in the hands of Dirk Schoysman, a flying Dutchman whose company provides a lot of Jaguar’s ‘Ring test pilots.  That was a full lap, not the usual touristenfahrten“ bridge to gantry” lap that is 1.5km shorter, and it was achieved despite light traffic.  That’s 25s quicker than the best XKR time I can find; the best XKR-S time is 10s quicker again.

My own Nordschleife experience was not in the same bracket, but I found the handling very predictable, and the huge torque was a real boon in the uphill sections and short straights.  The tyres and brakes worked really well; I only triggered ABS once despite some heavy braking, and there was no fade at all.  In fact, the car seemed to simply shrug off the experience without any drama.

I haven’t driven an XKR-S, but I’m sure the experience would be very similar.  However, the R-S remains out of my price bracket, and I don’t like the front-end treatment.  The 75 is a bit more subtle (if a big black monster can be subtle), and I really prefer its look, though I appreciate the practical reasons for the R-S body changes.

There are some curious omissions – there’s no air-quality sensor in the climate control, and they didn’t put the adaptive cruise or tyre-pressure monitoring options in, which I feel is a little odd in what was a top-of-the-line exclusive model. Dave Pook thinks some of this may be related to cooling; certainly, adaptive cruise isn’t an option on the R-S.  I’ve had to have a couple of minor issues addressed under warranty, and (like many XKs, it seems) the information and entertainment module is occasionally temperamental.

But overall, I’m extremely happy with the car; it’s quick but is happy to just rumble along, has sharp handling but isn’t harsh around town, loud when appropriate but not wearing on long trips – and something special, since there are only 20 just like it.  Thanks, Mike, Dave P, Matt, Jon, Michelle and Dave M; those evenings and weekends resulted in a real classic.

Editors note: Ross’s XKR 75 was part of the JEC Jaguar Timeline at Thoresby Hall on 22nd June 2014. View Details

 

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All information correct at time of publishing.