The TT Coupe project started not very promising, mainly because it was said to share VW Golf IV's platform, which has been notorious in handling. Partly because it was said to use Volkwagen's part-time Syncro 4WD system. Luckily, Audi did not receive all the things without alteration. It realised that the Golf's half-independent torsion beam rear suspension is the choice for cheap and space-efficient hatchback. No matter how hard they work, it would never achieve the high level of camber control that a sports car ask for. Therefore they developed a new multi-link suspension, mounted it on a subframe before attaching to the chassis in order to reduce NVH further.  

Then, it turned down the adoption of Syncro system for the benefit of handling. Since the Quattro system is deemed to be too large and heavy, and probably because it requires a longitudinally-positioned engine and drivetrain, it is also turned down. Surprisingly, Audi adopted a new system developed by a Swedish component maker called Haldex. The system uses a multi-plate clutch as the center differential for splitting torque between the front and rear axle, similar to the PSK system that Porsche 959 pioneered in 1986 (read AutoZine Technical School for more details). ABS sensors are employed to detect wheel spin, providing information for the computer to determine how much torque needed to be distributed to which axle, then implement the torque split by actuating the multi-plate clutch. Theoretically, nearly all the torque can be sent to either axle.  

Then comes the engine. The hottest TT Coupe Quattro is powered by the familiar 1.8-litre 5-valve turbocharged in-line 4, but power is dramatically raised to 225 hp by applying a maximum of 2 bar boost pressure from the new KKK K04 big turbo (still single turbo) and a pair of intercoolers. Surprisingly, Audi's engineers managed to achieve a broad torque curve from such a high boost engine - peak torque 206 lbft appears between 2200 and 5500 rpm ! To handle the additional torque, 6-speed manual transmission is used, and of course the 4-wheel drive.  

The TT Quattro is not a light car, thanks to the 4WD, it tips the scale at 1395kg, some 145kg heavier than its arch-rival Porsche Boxster. Yet its dimensions suggest it is a nimble car - 4041mm length is well below Boxster's 4315mm, 1764mm width is 16mm narrower. Because it need not to have a roomy rear seats space as the Golf, the wheelbase is shortened for 89mm, although still 77mm longer than the Boxster.  

Having finished the technical details, you must be hungary to know how it drives in reality. Here comes :  

Autocar's Peter Robinson (who is also Ward's European correspondent) test drove the TT Coupe twice, and he was very impressed. He described the engine as refined and tractable in low speed, pulls strongly since 3,000rpm and leads to a Boxster-beating performance. Its tremendous torque at a wide rpm band aids in-gear acceleration thus effortless driving. In addition, the gearshift is accurate and precise, with a heavy feel.  

Handling could be said as more satisfying than even the Ur Quattro (to be verified by other road testers). Unlike all other failed Audis, TT's steering is direct and quite heavy, with sufficient feedback. Its new 4wd system accompany with the new rear suspensions enable controlled power slide under hard cornering. Considering the degree of adjustability in cornering, this is a rare achievement for Audi. Grip is never in doubt. (By the way, you can feel the torque is shifting from the front to rear and vice versa during cornering) Body stays flat under provocation. Powerful brakes do excellent job. In terms of ride, TT is remarkably supple for such a performance car.  

However, to evaluate the real ability of TT, you should compare it with Porsche Boxster, a car which Audi intended to compete with. 
 

Audi TT faces Boxster

The Boxster lags behind the TT in acceleration. Objectively, the 204hp / 181lbft Porsche is no match for the 225hp / 206 lbft TT, especially when the Audi has an additional gear ratio and a superior torque curve. TT also goes faster in most corners, thanks to the advantage of 4WD's grip.  

But subjectively, Peter Robinson chose the Porsche 986 as the winner without a slight hesitation. As he said, "Audi, for all the cleverness of its engineering and the brilliance of its styling, is subtly compromised by its origins. The Boxster is a purer, more sharply focused and sensitive sports car."  

Compared field by field with the Boxster, he said the TT feels bulkier to steer. The steering is heavier all the time, yet it does not have the rich feedback and the high level of directness as the Boxster. In most cornering its attitude is correctable, but in some extreme cases where the car is pushed too overlimit, while the Porsche could easily be saved by opposite lock the Audi would lost control, or at least the driver has to fight very hard.  

The Porsche not only has sharper turn-in, it also has better body control, yet more absorbent ride. Audi's brakes are excellent, but the Porsche's are even more powerful and more progressive. Both gearchange is precise, only the Boxster's is lighter, thus encourage more shift.  

In terms of engine, the flat-six is smoother, more linear and sounds much more beautiful than the turbocharged straight four, although it is by no means as powerful.  

Therefore Peter Robinson concluded "Boxster is a better, more talented driver's car, a pedigree sports car that is simply more desirable even than the spectacular Audi."  

What the British tester didn't tell you is why the Boxster steers so sensitive and responsive. I tell you : because Boxster is mid-engined. Mid-engined cars, with the majority of mass locating near the center of gravity of the car, always have lower polar moment of inertia. As a result, they require less effort to steer and less effort to correct. No matter how brilliant the TT is, it has nothing to do with its high polar moment of inertia.  

Lastly, let me remind you that the Audi is based on the Golf, while the Boxster shares extensive components with the 996. They must be in different leagues. 
 

Development and production

The 180hp version

Road & Track's early test reported mild torque steer. 
 

TT Roadster

When evaluating an open-top car the chassis rigidity is always a key element. Without the hard top, chassis rigidity could be weakened a lot, thus deteriorate handling. Therefore most recent roadsters are designed with extra chassis reinforcement incorporated. Not least of which is the Audi roadster - torsion rigidity reaches 10,000 Nm / degree, which equals to Boxster and nearly matches Lotus Elise’s 11,000 Nm / degree. Considering the TT is based on Golf’s monocoque chassis, this is highly respectable. 

The reinforcement consists of strengthened door sills, a tower bar across the front suspensions, a beam connecting between the A-pillars which also holds the dashboard and at last 2 diagonal beams connecting the front suspension subframe to the door sills. The twin roll-over bars are also an integral structure to the chassis, so they are fixed rather than pop-up, unlike Mercedes or Volvo. Inevitably, these reinforcement bring the kerb weight from 1395kg to 1475kg for the 225hp version. Another price paid is the slight increase of aerodynamic drag from the already awful 0.35 to 0.36. Hood down, it becomes 0.39. However, I suspect the aerodynamic lift could be better than the Coupe in the absence of the swoopy roof. By the way, Audi is adding 19 kg dead weight to the rear end of the Coupe. 

Although 0-60 takes another 0.3 second, subjectively the Roadster feels as fast as the Coupe. The 225hp turbocharged four is still powerful yet tractable. Unless on very rough roads, body shake and steering column vibration are not exist, what a contrast to BMW Z3. As a result, the 4motion all-wheel-drive works as well as the Coupe to provide a superb handling, if not sensational. Considering the more life-style character of the Roadster, Audi softened the dampers by 10%, but this is not easily felt unless in extreme condition. 
 

TT revised to cure hi-speed instability

Unluckily, Ingostadt ignored AMS’s critic, allowing the snow ball to grow bigger and bigger. In September and October, 2 fatal high speed crash happened in Germany and was extensively reported. Another magazine, Stern, even interviewed many TT owners and published their scary experience. The incident has become a replica of Mercedes A-class. 

At last, Audi announced to recall all the 40,000-plus TT sold in Europe up to date, fitting thicker anti-roll bars, firmer dampers and a rear spoiler. The front wishbone is also revised.  

At the time being, Volkswagen / Audi’s promotion machine Vortex is still trying to defend the problem, saying it tested the TT with ex-F1 driver Michele Alboreto in a race track and found no sign of instability. The problem is, they chose the 180hp Quattro version, which is some 15mph slower than the 225hp version. Compare with the non-quattro version, it’s heavier rear end also benefit stability. Moreover, in a normal race track it is not able to reach a velocity as high as in Autobahn. 
 

TT 3.2 Quattro

If you remember, the 3.2-litre narrow-angle V6 was developed from the famous Volkswagen VR6 engine. Its latest version has been used in both the base Phaeton and Golf R32. It has a long lists of technology, such as 24 valves driven by 2 camshafts, continuously VVT at both intake and exhaust camshafts and a 2-stage intake manifold to enhance torque across a wide band, roller finger followers to reduce friction.... in the Volkswagen applications, this is already a marvelous engine. Nevertheless, Audi still find space for improvement, smoothening its intake and exhaust to generate more horsepower. The result is 250hp at 6300rpm. Torque remains unchanged at 236 lbft. The sub-product is a much-improved sound quality. Now it sings as beautiful as an Alfa V6, hard to believe. 

Compare with the existing 1.8 turbo, the V6 has the advantage of 25hp and 30lbft, but the car also carries 125 more kilograms (at 1520kg, it overweighs like a German beer-drinker), therefore power-to-weight ratio is barely improved from 161 to 164hp per ton. No wonder Audi claimed 0-60 is just shortened from 6.3 to 6.1 seconds. Top speed is claimed to be electronically limited to 155mph, but considering the drag coefficient of 0.35 this is not easy to achieve. 

Anyway, the new V6 is a big improvement from the four-pot, thanks to its smooth and linear power delivery (from 1500rpm to 6500rpm cut-out) and instantaneous throttle response. You know, a small turbocharged four-pot will never match a proper normally aspirated V6. The V6 feels far more eager and more powerful than the numbers suggest. Admittedly, the addictive engine note amplifies that feel.  

Apart from a V6 engine, the TT 3.2 also introduces a new DSG (Direct Shift Gearbox) automated manual transmission. The 6-speed gearbox uses two clutches and electro-hydraulic actuators to pre-select the next gear while running at the current gear. (See AutoZine Technical School for how it works). This results in ultra-smooth and responsive shift quality never experienced before in a manual-based transmission. It is so wonderful that you can simply forget about any F1, Selespeed or SMG, or even a pure manual gearbox - unless you insist nothing could be more enjoyable than shifting and clutching by yourself. To those purists, unfortunately, Audi TT 3.2 is not their cars, because DSG is the only choice. 

We have already described the key improvements the TT 3.2 made. The rest of the package is less remarkable. Predictably, it is equipped with larger 18-inch wheels (but tires are no wider) to accommodate larger front discs. Springs and dampers are stiffened. Steering ratio is shortened a little. Externally, the front air dam is bigger, so is the rear spoiler. That’s all.  

As before, the TT 3.2 is a front-heavy 2+2 coupe rather than a pure sports car like Porsche Boxster. Its quattro 4-wheel drive provides masses of grip, but the handling rarely inspires the driver. The revised steering setup is heavier and faster, but its feel is as dull as before. Equally disappointing is the lack of handling adjustability. Never think of any power slide or throttle oversteer, this car understeers at the limit. Therefore, although it has a superb engine and drivetrain, Audi TT 3.2 still fails to be a great driver’s car.