Although Volkswagen and its compatriot Audi were the first manufacturers to put dual-clutch gearboxes into their production models (in the early 2000s), it was Porsche that originally conceived the dual-clutch gearbox, for its 962C Group C Le Mans racecar in 1986.
The lone 962C with PDK (short for Porsche Doppelkupplung) tech failed to finish the race in Le Mans that year due to problems with the transmission. This DNF (motorsport-speak for “Did Not Finish”), plus the fact that mechatronics were not technologically advanced enough at that time, forced Porsche to abandon its experimental dual-clutch.
It wasn’t until 22 years later, in 2008, that Porsche revived PDK, introducing it to the 911 Carrera range.
Last year, the novel gearbox also went into the 911 Turbo, Boxster and Cayman, replacing the Tiptronic S torque converter automatic for all two-pedal models bar the Cayenne SUV.
By the time Porsche joined the dual-clutch bandwagon, Audi already had five years of experience with the transmission, having first employed it in 2003 in the 3.2-litre V6 flagship variant of the original TT.
The hottest model in today’s second-generation TT range, the RS, made its debut just over a year ago with a 6-speed manual gearbox.
Without an auto option, it was hard for the TT RS to sell well in Singapore’s premium sports coupe segment, where most drivers loathe operating a clutch pedal and changing gears themselves. They will welcome the newly arrived S tronic version.
Inevitably, the greatest rival to the semi-auto TT RS is the Porsche Cayman S, widely regarded as the most driver-focused car in its class. The Audi must “overtake” the Porsche if it wants to dominate the high-performance coupe category.
In terms of styling, the Stuttgart “alligator” trails the Ingolstadt upstart. The TT’s dynamic shape is enhanced by RennSport design tweaks such as honeycomb inserts for the radiator grille, 19-inch alloy wheels, double oval exhaust tailpipes and a bespoke fixed rear wing.
Comparatively “quieter”, the Cayman S looks little different from the non-S car. Only the eagle-eyed will notice the “S” badge on the boot lid and the twin exhaust pipes on the S (it’s a single rectangular pipe on the regular Cayman).
Moreover, the 18-inch wheels look lost under those sizeable fenders and they don’t have the outright visual appeal of the TT’s 19-inch rims. I have to admit I’ve never been a big fan of the Cayman’s looks – to my eyes at least, the 911 is prettier and better proportioned. Next to the sleek and petite TT RS, the Cayman S appears clumsy, heavy and just a little ugly.
The Audi trumps the Porsche again when it comes to specifications and acceleration. While the Cayman S has 320bhp and 370Nm from its naturally aspirated 3.4-litre flat-six, the TT RS has a 2.5-litre turbocharged five-pot that musters 340bhp and a whopping 450Nm.
Coupled with a lightweight part-aluminium body, the engine’s strong output translates into impressive pick-up – zero to 100km/h in a mere 4.3 seconds, even quicker than the manual 6-speeder.
In comparison, the Cayman S specified with 7-speed PDK and the optional Sport Chrono Package (set to Sport Plus, the “fastest” setting) hits 100km/h from standstill in 4.9 seconds (it’s 5.1 seconds in standard spec).
Any car that can do the century sprint in under five seconds can be considered fast, while any timing difference of more than half a second is significant.
So, the Cayman S is fast but the TT RS is staggeringly faster. The speedy Audi can even outrun the 911 Carrera S and GTS, at least up to 100km/h or so.
On the autobahn, the TT RS is electronically limited to 250km/h (the usual German “restraint”) while the Cayman R runs out of puff at 275km/h. Audi offers the option of removing the speed governor, which would allow the TT RS to reach a terminal velocity of 280km/h.
This option is unnecessary in Singapore (or Malaysia, for that matter), but it includes a carbon fibre engine cover that some enthusiasts might deem necessary for bragging rights.
How the two coupes perform on the road reflects the performance figures on paper, which come to life in a heartbeat when you put the pedal to the metal.
With its 450Nm available from just above idling speed, the Audi’s five-pot motor feels more instantaneous and responsive than the Porsche boxer-six at low and medium speeds, making its high performance more exploitable in most situations. The TT RS feels livelier than the Porsche, regardless of driver talent or driving condition.
The flat-six in the Cayman S thrives on revs – not surprising when its peak torque of 370Nm is produced at a relatively high 4750rpm. Unlike the get-up-and-go power delivery of the Audi, the Porsche unit needs loads of revs before it can deliver the goods.
Apart from the V10 R8, the TT RS is the best-sounding Audi out there, thanks to its distinctive 5-cylinder snarl that really reminds us of the glorious noise made by Group B quattro rally cars back in the mid-1980s. The exhaust note of the TT RS, however, should be louder – solve this “problem” by specifying the sports exhaust system from the factory.
Also making a nice noise is the Cayman S. Its flat-six engine, just like that in the 911 models, produces a mechanical symphony that has been synonymous with Porsches for as long as we can remember.
The Cayman’s mid-engine layout also means that this intoxicating soundtrack comes from behind your ears rather than from the front, further tickling your senses and making the drive feel like a special occasion – more so than in the TT RS.
In the dual-clutch duel of PDK versus S tronic, the Porsche system is difficult to fault. Put it into Sport Plus mode and it swops gears in a crisp, instantaneous manner.
The Audi device is similarly incisive. More importantly, its ratios and gearchanges are better suited to the engine than those of the manual ’box, enabling the grunt and torque curve to be fully exploited.
One advantage of S tronic over PDK is the manual override – the paddles behind the Audi’s steering wheel are far more intuitive than the Porsche’s illogical shift buttons.
Racy the TT RS might be in a straight line, but in the twisties, it has no clever answer to the Porsche. Don’t get me wrong, the Audi is not a bad-handling car – it feels nimble and light on its feet.
But as I discovered on two different track days in a TT RS at Sepang, the Audi lacks front-end grip on the limit and without the trick differentials of the RS5, it is a bit stubborn turning sharply into bends at serious speeds.
The Porsche feels more poised when pushed hard, maintaining its natural composure even in extremis. It is beautifully balanced, perfectly planted, unerringly stable and keener to change direction than its competitor, which has more grip than finesse.
The mid-engine, rear-drive layout and expert chassis tuning of the Cayman S are responsible for this positive behaviour.
Piloting the Porsche is so satisfying that you feel like part of the car. Its steering is connected directly to the tarmac ahead, and you can sense the road surface through your bum.
I daresay that the Cayman S steers even more precisely than the mighty 911. The steering of the TT RS is well-weighted and accurate, but compared to the telepathic Porsche rack, it is lifeless and it lacks valuable feedback from the chassis.
It’s been a good battle so far between these two sports cars. Now they fight in dollars and sense – and the TT RS doesn’t win. It costs just a few thousand bucks less than the Cayman S, which either makes the Audi overpriced or the Porsche undervalued.
However, the TT RS is fully equipped with nearly everything standard-fit, whereas the Cayman S (like other Porsche models) has a brief list of amenities and a much longer list of optional fripperies.
Tick a few boxes for choice upgrades and the Porsche’s price balloons, making the TT RS look like a smarter investment. Then again, the Cayman S comes with a five-year/100,000km free maintenance programme, provided by the official Porsche dealership as a value-add that is also transferable to the next owner.
So, which of these two cars is the superior dual-clutch driving machine? It’s a tough choice. The TT RS is more stylish and more aggressive, while the Cayman S is more entertaining, purer and more prestigious. Alright, I prefer the Porsche.
Porsche Cayman S 3.4 (A)
ENGINE 3436cc, 24-valves, flat-6
MAX POWER 320bhp at 7200rpm
MAX TORQUE 370Nm at 4750rpm
GEARBOX 7-speed dual-clutch with manual select
0-100KM/H 5.1 seconds
TOP SPEED 275km/h
CONSUMPTION 10.6km/L (combined)
PRICE INCL. COE $334,888 (as of June 2011)
Audi TT RS 2.5 (A)
ENGINE 2480cc, 20-valves, inline-5, turbocharged
MAX POWER 340bhp at 5400-6500rpm
MAX TORQUE 450Nm at 1600-5300rpm
GEARBOX 7-speed dual-clutch with manual select
0-100KM/H 4.3 seconds
TOP SPEED 250km/h (governed)
PRICE INCL. COE $331,873 (as of June 2011)