Knockhill Supercar Event
I attended the first of two track events on consecutive weekends at Knockhill last Sunday. The World of Supercars was a showcase for the spectating public to see and hear some of the best sports cars made, and also to observe the cars performing at speed on the track. All the major marques were represented, AC, Alpine, Caterham, Ferrari, Jaguar, Lister, Lotus, McLaren, Mercedes, and many others, including, of course Porsches of all engine configurations. I really enjoy participating in events such as these. The wide variety of machinery represented is always interesting, and presents the opportunity to chat with owners of other sports car marques.
The weather forecast for the day of the event was dire. However, upon arrival at Knockhill for the signing-on at 9.00am, the sky was bright, if overcast, and most importantly the track was bone dry. I had taken the option of three 15 minute track sessions at a very reasonable £75. With two sessions in the morning, it looked promising for some dry track time before the heavy rain forecast descended upon us. The track cars were split into two groups. I was assigned to Group 1 which was a sparse collection of older Ferraris, a 997 GT3, and a 987 Boxster. Free tuition was available on request from a current Knockhill racing driver based in the pit lane.
My main objective was a shake-down track test with my 718 Cayman GTS, but also to check out the GpPro mounting, and configure the Porsche Track Precision App for the PCGB Knockhill track day the following weekend. Having previously done many laps at Knockhill with my previous 718 Cayman S, which had an identical chassis spec, I was keen to establish the degree of performance advantage the GTS would have over the more humble "S". As previously reported on this thread, the on-the-road differences in performance between the two models is certainly noticeable, but not to a huge degree. I was anticipating more of a difference in track performance between the CS and the GTS, especially on a circuit I know extremely well. I was not to be disappointed.
I took up the offer of free tuition from Malcolm, the resident racing driver, who accompanied me for 5 laps with the purpose of tweaking a few extra tenths at two challenging sections I felt needed improving on, the chicane, and Clark's corner at the back of the circuit. The line of approach to these two corners is critical if you are intent on putting together a quick lap. Malcolm pointed out subtle line changes at both corners which proved very helpful in subsequent laps when I was out on my own in the car. I cannot stress highly enough the value of professional track tuition. Even at my advanced age and on a track I know well, tuition is always of value even to the experienced track day driver.
The 718 Cayman GTS PDK is essentially a luxuriously equipped touring car. It is also a superlative track performer. The extra power and torque of the GTS over the S is clearly discernible at several points on the Knockhill track. Exiting Turn 3, which was tested in both 2nd and 3rd gears, with 3rd being entirely appropriate when one-up, exiting Turn 6, and most significantly, exiting Turn 7 the hairpin leading onto the uphill start/finish straight. The extra torque provided a sling-shot pull up the long uphill drag, culminating in a terminal speed of 122mph under the Beatson's bridge. Impressive stuff for a mainstream Cayman.
The chassis, especially at the rear, is a further development of the 981 Cayman GTS, sitting 10mm lower, a wider track on wider wheels, with revised anti-roll bar mountings, extra subframe bracing, and additional dynamic engine and transmission mountings. The resulting sum of these developments together become blatantly apparent on the race track, far more so than on the public roads. The body roll, pitch, and squat, are so tightly controlled on the 718 GTS, especially so when Sport Plus is selected, that the grip and handling is on a level previously occupied only by the best GT Porsches of less than a decade ago. Knockhill circuit is a severe test of any chassis, and woe betide any car that is prone to understeer. Audis take note. The sheer poise and balance of the GTS made light work of the blind dips and crests, and the improved steering feel and quicker rack gave this particular driver the confidence to commit to the roller coaster ride that Knockhill provides in spades. The PCCB ceramic composite brakes are absolutely superb. The confidence conveyed to the driver through the consistent reassuring feel of the brake pedal during the two 120mph stops, made this particular option worth every penny in my book.
Now to the lap times. It was a stroke of fortune that my particular track group had no McLarens, Caterhams, or Skyline GTR's. Only a sole 997 GT3 providing a token opposition to my 718 GTS. On the twisty and dippy sections the 997 GT3 showed its age, with the driver deciding to give way to my quicker 718 GTS on the following straight. Once clear of traffic, I posted a reference lap time on the PCM of 1.01.2 seconds which was a respectable time for a starter. My best lap of the day, just as the rain started spitting, dipped into the 60 second bracket which was encouraging for a 72 year old retired racer. Given a clear track, and with all the planets aligning, I would say a sub-one minute time is attainable with my car on the Michelin PS4S tyres. While on the subject of tyres, I will repeat my statement made last year, that the PS4S N0 has a very short track grip durability. In my experience only two 61 second laps of Knockhill were possible before the grip melted away and the PS4S became all squirmy and slidey. They are after all essentially a road tyre with outstanding wet grip performance. The wet grip is achieved at the expense of consistent dry grip on the race track. This is where Michelin Cup2's would raise the game of the 718 GTS performance on the track. Put simply, Cup 2's have the hot lap durability the PS4S lacks. For those interested, my geo settings have proved ideally suited for track use with consistently even wear across the whole tread width, both front and rear. My tyre pressures for the day were set at 2.1 Bar (30psi) cold. Pressure increased to 2.5 Bar (36psi) following a 5 lap stint. No graining or overheating evident on the treads afterwards.
Next weekend the PCGB track day calendar visits Knockhill. The weather forecast is not great, but hopefully I'll get some dry laps in at some point during the day. A report will follow.
Some photos below for your interest.
Brian
At speed on the uphill straight with tutor Malcolm providing helpful tips. (Photo by Paul Barlow)
]
