Sep 16

Sep 16 Guide: TT goes Renn Sport - a Historical & Technical Appraisal of the Audi TT RS Mk2

<<<AUDI PORTAL

BACKGROUND

In the midst of a trend for unimaginative retro-themed automotive styling around the turn of the millennium, Audi broke with convention to create a genuinely fresh design language for some of its new models.

By far the most exciting of these was the TT which Audi conceived for a highly anticipated move into the small Coupe and Roadster market.

With its Bauhaus-inspired look, the first generation TT came to be regarded as one of the most significant cars of the early 21st century and customers flocked to Audi showrooms. Between 1998 and 2006, nearly 270,000 were sold which represented a massive commercial success for the Ingolstadt company.

Audi subsequently looked to build on this with the advent of the second generation TT (internal code 8J) revealed in April 2006 and based on the VAG’s A5 (PQ35) platform shared with models like the Audi A3 and Q3, the Volkswagen Golf, Jetta, Scirocco, Beetle and Touran plus various Skodas and Seats,

Having initially been available in either front or all-wheel drive trim with a turbocharged 2-litre 197bhp inline ‘four’, or as a four-wheel drive Quattro with normally aspirated 3.2 247bhp V6, Audi went on to offer an entry-level turbocharged 1.8-litre TT with front-drive only from 2007. For 2008, output of the 2-litre motor was increased to 208bhp and an all-wheel drive 2-litre turbocharged diesel was added to the range.

However, perhaps the most significant arrival for 2008 was the hottest TT yet, the TTS, which came exclusively in four-wheel drive Quattro trim and was powered by a heavily revised 268bhp version of the existing 2-litre inline four cylinder motor.

With its increased output, sport-tuned chassis and array of cosmetic enhancements, the TTS proved a popular alternative to Porsche’s Boxster and Cayman which had ruled the premium small sports car sector almost unopposed.

Although well received, the TTS’ rein as the top ranked second generation TT did not last long for, at the Geneva Motor Show in March 2009, Audi unveiled what many enthusiasts thought should have been offered a decade earlier: a TT RS.

Like every one of Audi’s revered line of Renn Sport models which stretched back to the original B4 RS2 of 1994/’95, this latest RS was developed by the team at Quattro GmbH in Neckarsulm. Significantly though, for the first time in Audi RS history, assembly took place elsewhere (in this case alongside the rest of the TT range at Audi’s Gyor plant in Hungary).

Produced as either a 2+2 Coupe or 2-seat Roadster, the TT RS most notably featured a brand new turbocharged 2.5-litre inline ‘five’. Such an engine configuration had last been used by Audi for the original Quattro of 1980 to 1991. A new short-shift six-speed manual gearbox was also developed to handle the mass of power and torque generated.

As per the TTS, the RS could only be ordered in four-wheel drive Quattro trim. Production began in July 2009 for the 2010 model year, but Audi did not offer the RS in the United States until the 2012 model year.

CHASSIS

Like every second generation TT, the RS was based around a spaceframe bodyshell that, in the interest of weight distribution and reduction, was fashioned from 69% aluminium and 31% steel.

The wheelbase measured 2460mm and a 60-litre fuel tank was located over the rear axle.

Suspension was via MacPherson struts up front and a four-link arrangement outback with an anti-roll bar installed at either end. The front suspension was part-fabricated from aluminium and the rear four-link layout was unique to the TT (whereas the first generation derivative had shared substantially more of its chassis hardware with the Volkswagen Golf).

As per the TTS, ride height was 10mm lower than the rest of the TT range, but stiffer spring and damper rates were unique to the RS.

Also specific to the RS was an uprated brake system that comprised two-piece cross drilled and radially vented 370mm diameter discs with four-piston gloss black RS-branded calipers for the front axle and vented 310mm diameter items with twin-piston calipers at the rear.

The standard issue wheels were handsome 9 x 18 five-spoke rotor design items shod with 245/45 ZR18 tyres.

For the RS, the normal TT’s speed-sensitive steering was recalibrated for a sharper response and greater feel.

ENGINE / TRANSMISSION

It was in the engine bay that the Renn Sport TT’s real party piece could be found: a virtually bespoke Type EA855 all-alloy 2.5-litre inline ‘five’ that was effectively half of the Lamborghini-derived V10 fitted to the contemporary RS6.

Transversely mounted, the specification comprised dual overhead camshafts, four valves per cylinder, direct petrol injection and wet-sump lubrication. Turbocharged at up to 1.2 bar and intercooled, the EA855 motor displaced 2480cc thanks to a bore and stroke of 82.5mm and 92.8mm respectively.

With compression set at 10.0:1, peak output was 335bhp at 5400-6500rpm and 332lb-ft at 1600-5300rpm.

For comparison, the four cylinder TTS produced 268bhp at 6000rpm and 258lb-ft at 2500-5000rpm.

Unlike most engines of the time, the RS motor was not buried below a plastic cover and instead featured fully exposed crackle red cam covers.

Activation of a Sport button located on the centre console sharpened throttle response and opened a flap inside the left-hand tail pipe to produce a deeper exhaust note.

Whereas the rest of the TT range could be ordered with a manual or semi-automatic S-tronic gearbox, the TT RS was initially offered exclusively in manual trim because the torque developed by its rip-roaring new engine was too much for the existing S-tronic unit to handle. However, it was also too much turning power for the manual ‘box used in lesser models, so Audi had to modify the six-speed unit found in Volkswagen’s Transporter van which was suitably uprated with a new short-shift mechanism.

Also fitted was a specially adapted version of the latest multi-plate Haldex Traction clutch that came with a constant velocity joint before the Cardan propeller shaft. A compact rear-axle differential was similarly enhanced to handle all that torque.

Torque was normally split equally between the front and rear axles, but if required the Quattro permanent all-wheel-drive system was able to direct the bulk of the power to the back axle for improved dynamics.

A three-stage Electronic Stability Programme was fitted as standard.

BODYWORK

In typical Audi Renn Sport fashion, the TT RS was enhanced with a number of sporty bodywork additions.

A new front bumper assembly featured enlarged, more aggressively profiled corner intakes with three instead of four-blade directional vanes and a deep body coloured front spoiler that spanned the central zone underneath.

Down each flank were deep body coloured skirts.

At the back, Audi installed a new fully vented rear apron complete with an integrated matt black diffuser. Two massive oval tail pipes replaced the four outlet system used by the TTS. Further up, a twin pylon-mounted fixed rear spoiler was installed instead of the original retractable item although the latter was available as a no cost option.

Custom honeycomb pattern grilles were used front and back along with TT RS badges.

Audi’s trademark LED daytime running lights were fitted as standard.

Body panels were fabricated from a mix of steel, aluminium and plastic composite.

INTERIOR

As per the exterior, most of the interior equipment fitted to the RS was lifted from the standard TT or TTS, albeit with a few special touches to reflect this latest variant’s status as the costliest and sportiest in the range.

A small diameter flat-bottomed three-spoke steering wheel was imported from the TTS to which Audi added a TT RS insignia and a dimpled as opposed to smooth leather rim.

The 8000rpm rev counted was also shared with the TTS but similarly now featured RS branding. A 310kmh / 200mph speedometer was another RS-only feature. In between these two large dials were the familiar small gauges for water temperature and fuel along with a customised digital screen through which all manner of additional information could be accessed to include a lap timer, boost pressure and oil temperature.

Sports front seats were heated and featured TT RS-branded headrests. Uniquely, the TT script was also worked into the door panel inserts for the RS.

Upholstery was a mix of leather and alcantara suede with an RS-specific black headliner.

Automatic climate control was fitted as standard.

OPTIONS

Audi offered the TT RS with a wide array of optional extras.

Audi Magnetic Ride was an adaptive ride system with magneto-rheological dampers whose damping resistance rapidly varied according to suit the conditions.

The standard 18-inch five-spoke wheels could be configured in a two-tone high gloss black and red finish. 19-inch wheels on 255/35 tyres were also available in the five-spoke rotor design (in plain, titanium or red/black finish) or a six-twin-spoke style as fitted to the contemporary RS4. The RS4 style rims could also be ordered with a 20-inch diameter on 255/30 tyres.

Other options included a sports exhaust, top speed de-restriction (to 174mph), manually-operated Recaro RS bucket seats from the RS4, a matt aluminium exterior pack, exterior mirror casings in visible carbonfibre-reinforced polymer (CFRP), Silk Nappa or Fine Nappa leather upholstery, Audi Navigation Plus, a Bose twelve-speaker audio system, a six-disc CD changer, the Audi Music Interface with iPod integration (not available with the six-disc CD changer), USB connection, Bluetooth phone preparation, Isofix preparation, cruise control, matt brushed aluminium cockpit inlays, rear parking sensors and the aforementioned electronic rear spoiler from the regular TT (in place of the RS-style fixed item).

A couple of option bundles were also available.

The Tech Package comprised adaptive xenon plus headlights with LED daytime running light technology (fitted as standard in most markets), Audi Navigation Plus, the twelve speaker BOSE audio system, the Audi Music Interface with iPod integration, rear parking sensors and ambient LED lighting.

The Sport Exhaust Titanium Package included 19-inch five-spoke rotor-design wheels with titanium finish, a titanium finish Audi grille and the sports exhaust.

WEIGHT / PERFORMANCE

As a consequence of its uprated five instead of four cylinder engine, the TT RS came in a little heavier than the existing TTS: the RS Coupe weighed 1450kg (up from 1395kg) while the Roadster was 1510kg (up from 1455kg).

Performance figures were much improved though and both RS variants could hit 0-62mph in just 4.5 seconds which was five tenths faster than the TTS.

Top speed was once again electronically limited to 155mph, but if completely unrestricted in excess of 180mph was said to have been possible.

S-TRONIC GEARBOX OPTION

Having exclusively produced the TT RS with a manual gearbox for the first twelve months of production, Audi added a semi-automatic Direct-Shift Gearbox (DSG) dubbed S-tronic for the 2011 model year.

Because the existing six-speed S-tronic unit had not been able to cope with the output of the TT RS, a special seven-speed unit had to be developed. If specified, S-tronic added 25kg to the car’s weight but cut the 0-62mph acceleration time by two tenths of a second (down to 4.3).

TT RS PLUS

Audi introduced a further enhanced TT RS at the Geneva Motor Show in March 2012: the TT RS Plus.

At the heart of this uprated variant was a more potent engine with a revised inlet manifold, increased boost pressure and some handsome under-bonnet visible CFRP.

Peak output went from 335bhp to 355bhp at an unchanged 5400-6500rpm although this was at the expense of a little torque (332lb-ft at 1600-5300rpm as opposed to 343lb-ft at 1650r-5300pm). A sports exhaust with black tailpipes was fitted as standard.

Also included as part of the RS Plus package were 19-inch five-spoke rotor style alloy wheels, CFRP door mirror housings and a single frame radiator grille with matt aluminium surround and polished anthracite mesh.

Inside, Audi fitted a gear knob with the TT RS Plus logo along with the Audi Navigation Plus, Bluetooth phone preparation and Audi Music Interface complete with iPod connectivity as standard.

Each TT RS Plus automatically came with the higher 174mph top speed restrictor.

0-62mph times were cut by two tenths of a second (4.3 seconds for the manual and 4.1 seconds for S-tronic).