Case Study Former PalmerSport XKR
I thought this month it would be interesting to take a case study where we have put all we have talked about so far into one car and see the difference it has made.
Jaguar launched the new XK (X150) in 2006 replacing the highly successful X100 that had enjoyed a ten-year run. The X150 was a big departure from what had gone previously with its all-new aluminium body and very different chassis dynamics. Ex-F1 and Le Mans driver Jonathan Palmer was big fan of the new Jaguar and ordered a fleet of ten cars for his PalmerSport track experience at Bedford Autodrome. Palmer commented at the time “The PalmerSport event has earned a reputation for being the best driving event in the world. Part of achieving this is to continually evolve our programme with a new headline car each year. Inevitably it gets tougher to improve upon the best, but the Jaguar XKR has ticked all the boxes. Stunning looks, incredible performance, a beautifully balanced chassis, glorious sound, and outstanding value”.
As Palmer said they were constantly evolving their offering and having run the XKR’s for a few years PalmerSport put the cars up for sale. We got an opportunity to look after some these cars for customers who purchased them as track day toys and to purchase a couple of our own. Out of the ten cars that were built I think we have looked after as many as seven at some point, so we know a fair bit about them. Palmer left the powertrain pretty much untouched and the actual modifications that were done were more to reduce weight, add cooling, improve handling and adding the necessary safety features such as roll cage, electric cut off, fire extinguisher, race seats and harnesses. Visually you cannot miss the massive rear wing which adds important downforce. The looks mimicked the Apex Racing team cars that were being run at the time by Palmer’s friend Richard Lloyd.
Forgive the PalmerSport history lesson but I thought it was important to establish what base we were starting from before we added our own modifications to these cars. We can understand why PalmerSport didn’t want to do much tuning wise, the cars were being put through their pace’s day in day out around the Bedford circuit, 420 bhp was power enough and no doubt longevity was the aim. We use the cars four or five times a year for track days, and we have one road registered so we can drive it to and from events and test components on the road. As we don’t do the track miles that PalmerSport were doing we lightly tuned the cars, similar to a stage one that we would offer for the 4.2 supercharged road cars, i.e. our SR smaller upper pulley and a re-map. The next stage beyond that was adding our own in-house built custom exhaust and 200-cell race cats so the V8 could breathe more freely. Again, this is something we offer from Swallows for road cars. The result of the tuning on the Palmer cars was a power uplift of around 50bhp, improved throttle response and moving the torque curve to a more usable position.
Having added some useful additional power, we wanted to improve the handling and brakes. PalmerSport had uprated the suspension to some degree with dampers from the OEM supplier Bilstein. At the time these cars were built there was probably limited choice for upgrading the dampers without having highly expensive custom units made, so Bilstein’s were probably the best off the self-option available. We felt the Palmer XKR’s always had a touch of oversteer despite that massive rear wing. Oversteer is common in rear-wheel-drive cars and so isn’t always easy to dial out. Working with AVO we created an adjustable damper kit for the X150, being able to adjust bump and rebound. Bump being an upward movement or compression of the suspension. Rebound is the opposite of compression and is the extension or return of the suspension back to its original position. Having an adjustable damper kit allowed us to have greater control of the suspension characteristics and to get the handling of the car to a more neutral feel by adjusting bump, rebound and the spring rate. In addition, we polybushed the suspension with Powerflex polybushes which is an upgrade we will talk about in more detail in a future article but one we highly recommend not just for track cars but all modern road Jaguars too.
We talked last month about the role that tyres play and how they can significantly alter the way a car behaves. Our PalmerSport XKR’s have been a useful testbed for many of our performance parts, not least tyres. We have experimented with a range of tyres from Pirelli, Nankang and most recently Yokohama. Because one of our PalmerSport XKR’s is road registered it gives use the opportunity to not only test our upgrades on the track but also in normal road conditions. This allows us to test combinations of suspension settings with different tyres in a range of environments. Tyres are an important component in suspension set up. We are currently running the Yokohama Advan Sport V107 on our road registered car and can feel a massive improvement in the way the car behaves on the road both in dry and wet conditions.
PalmerSport opted to use the Alcon brake upgrade on their cars which was Jaguar offered option at the time. This was actually a really good option from Jaguar on the X150 and an excellent brake package with 400mm front discs and 350mm on the rear. If you have these specified on your road car you will know how good, they are. As we have said in the past at Swallows we have developed brake packages with Tarox which means that we can offer their S2000 as a cost effective quality replacement discs along with Tarox pads in range of compounds. On our XKR’s we have run and tested a combination of the original Alcon’s with different discs including Tarox which only adds to the quality of the original choice.
The PalmerSport XKR’s really have been a perfect mule for Swallows to test performance upgrades in different environments. This gives us great deal of confidence when offering Swallows Racing performance parts for road and track cars.
