Monday, May 26, 2014

Taking a Porsche Cayman to an Autocross

A post by Mike Scott on Rennlist. A nice account worth re-posting!

>Like you, I also succumbed to the "dark side" 2 years ago and added
>a 2009 Cayman S with PDK and Sport Chrono to the stable alongside
>the 87 911 Targa.Â
>The 911 has now been retired from track duty and I have done a
>number of DEs with the Cayman. Â You are going to love it! Â One
>suggestion - for an autox, I would start out with Sport instead of
>Sport+. Â At least for the first run :) Â You might find the car
>will sometimes shift in the corners, which can be pretty
>disconcerting if you are not expecting it. Â However, the PDK shifts
>so fast and smoothly it doesn't upset the balance!

Well, a report was requested, and though I feel a little funny about
writing to the 911 list about my first autox experience in a Cayman,
here it is:

The PCA-SDR Zone 8 event at Qualcomm yesterday attracted 122 entrants
from several Lo Cal regions, including 100 Porsches as well as about
20+ Exhibition class entries (a Ferrari, a couple of Lotus Exige S
cars, plus a smattering of Miatas, S2000s, BMWs, VWs, a Mitsu Evo,
and a BRZ). The weather was very cool, in the 60s and overcast with
drizzle in the morning after several weeks of unseasonably hot and
dry weather that had spawned wildfires that made national news. The
site at Qualcomm is a relatively nice venue for autox, although the
asphalt surface of the west lot is deteriorating due to a lack of
maintenance by the city. The local car clubs have taken on the burden
of filling the ever-expanding potholes themselves over the last few
years by organizing their own work parties and buying the concrete
out of club coffers. The lot has a fairly large area with almost 100'
of vertical elevation change from north to south, though, allowing
for large, flowing courses with camber changes not possible on a
completely flat site, and elevated trolley tracks at the south end
provide some shade for the cold pits (or shelter from the rain, as
the case may be).

My day started early, arriving at 6:15AM to set up the tech station
and inspect all the entrants' cars before 8:00. Due to sound
restrictions, no cars are allowed on track before 9:00AM or after
5:00PM, and all must conform to a 93db @ 100' maximum noise level.
Due to the number of entrants and time limitations, each of the 6 run
groups had a total of 12 hot laps for the day, divided into two
practice sessions of 4 laps each, and a timed run session in the
afternoon of one warm-up lap and 3 timed runs. The course was fairly
long and twisty, with a couple of sections straight enough to hit
70mph+, and one 3-cone slalom element in the middle.

Having only had the Cayman in my possession for 6 days before the
event, I had not prepared it at all--no competition alignment, no
sticky tires, no harnesses, etc., just bone stock. Zone 8 has a
ruleset that allows for 16 Competition Classes (CC01-CC16) and 9
Street Stock classes (SS01-SS09), arranged from slowest to fastest
speed potential. They are determined roughly by HP/WT ratio combined
with additional points for modifications. No mods are allowed in SS
classes, though, and tires must have a minimum of 140 treadwear
rating. CC classes are wide open, with any mods and R-comp tires and
slicks allowed. The stock 987 Cayman S slots into SS04 class, along
with the 987 Boxster S and the 981 Cayman and Boxster (non-S) models.
The P-Zero tires the Cayman came with meet the treadwear limitation,
so that's where I ran it.

I missed the track walk due to working tech, but the driver's meeting
was over early, and my run group was the first out, so we were
allowed a parade lap at reduced speed and low RPM before the 9:00AM
start, which gave me a much-needed look at the track. I had requested
that the CDIs not assign me a student for this event, since I was
learning a new car, which thankfully relieved me from the
complication of having to explain to someone that I didn't know what
I was doing in this car yet, or what to expect from it. Having never
run the Pirellis before, I started with the manufacturer's pressure
recommendation (32F/34R). I took Mike's advice above and ran with the
car in Sport mode for the first 3 laps, finding the track and
building speed progressively, letting the PDK choose all the shift
points. The power steering and power brakes required some
acclimatization, as none of my older cars ever had any assist. Once
used to how light a touch the car needed, it inspired nothing but
confidence. The handling was excellent and well-balanced, seeming to
generate a lot of grip from the street tires, until I started pushing
harder on corners and the fronts started giving up. A little wider
front tire and some more camber in the front would help with the
understeer, I think, but since that option wasn't  possible on the
spot, I just changed my driving style to what had worked for me in
other mid-engine cars with a bit of push that I've run in the past,
braking deeper and later and trail-braking nearly down to the apex to
keep the front tires loaded while turning in, then getting on the
throtttle as the steering wheel straightens. There were not enough
straightaways to really reward a late apex and an early throttle
application, so this didn't give up too much time. On the 4th lap, I
felt comfortable enough to push the Sport+ button, and it did make a
noticeable difference. Throttle and brake responses were tightened
up, and shifts were crisper. On the slowest corner of the course, a
very tight right/left combo, the car did surprise me by shifting down
to first briefly, but the speed was slow and revs were well-matched
so it didn't upset the car. One thing I really missed was the
dedicated race seat and 5-point harnesses in my other cars. I was
really happy not to have to use my left foot to clutch, and could
just brace myself on the dead pedal with it. The sport seats in the
car are comfortable, but nowhere near as supportive as a race bucket.

In the second session, I lowered the cold pressures 3 psi, as when I
started pushing the car harder in the first session, I noticed the
tire pressures increasing to over 40psi in the rear and 37 in the
front, despite the cool conditions. The TPMS display seemed to
correspond fairly accurately to the readings I got in the pits with
my Longacre gauge, and the scuffing on the tire tread was showing no
rollover onto the shoulders at all. I ran all four laps in Sports+ to
get used to the different parameters of throttle, braking and
shifting. I found by being lighter and smoother on the throttle
exiting the really tight corner, the car would not downshift to first
on the exit, so it is possible I was hitting the "kickdown" switch on
the gas pedal by being too abrupt going to full throttle. I hit one
cone hard with the right front bumper while trying to straighten out
a kink in one of the fastest sections too much, but that was the only
mark on the car all day.

In timed runs, I took my warmup lap to get the tires and brakes to
temp, and then laid down a semi-aggressive but smooth lap to get a
clean run of 1:15.66 in the bank. The second lap I stepped up the
pace and shaved 3/10s off for a 1:15.38 lap. Then I figured I'd go
for broke on the last lap and turned off the PSM to see if it was
holding me back. I ended up overdriving the car and sliding around
too much, and ran a 1:16.16. It felt fast, but it wasn't. All in all,
I was very happy with the car's performance, considering the setup
was not optimized at all. My best time was good enough for the class
win in SS04, and I was 16th fastest out of the 100 Porsches there
(two "X" cars also just nicked me--one of the Lotus Exiges and the
highly modified BRZ driven by Derek Punch, a national-level SCCA
autocrosser). Most importantly, I was the second fastest car on
street tires, with only a 991 C2S in SS07 running a time 7/10s of a
second faster than mine--everyone else was on R-compounds. A 997 GT3
RS had TTOD with a 1:11.58. My friend Carl Vanderschuit (whose name
some may recognize if you saw the "King of the Curve" competition on
Speed TV) suffered a broken front swaybar on his highly modified
Boxster and only managed a 1:14.45, probably a second or two slower
than he should have been. Full event results are here:

With a little better setup, this car definitely has the potential to
be a really fun and fast autocross car that is exceptionally easy to
drive. I have to say it wouldn't hurt to have another 70 HP or so to
be able to squirt out of the corners like a GT3, but that won't
happen anytime soon. It is too nice to modify heavily, and still
under warranty until 2017, so I am not going to go crazy with a 3.8
X50 transplant or anything, fun as that might be. I will be on the
list for a Cayman "GT4" if Porsche ever decides to make such a car,
though. In the meantime, I'll probably just get a competition
alignment and a set of 18s with some 245/275 Advan Neovas on them and
keep autocrossing in SS class. With the health issues I've had the
last 18 months, I'm afraid my big track days are over, but I can
still get a cheap thrill in the local parking lot at Qualcomm.

No comments:

Post a Comment