This year marks the 40th anniversary of Audi’s glorious relationship with the in-line five. We chart the alliance and drive its latest beneficiary – the 394bhp, £51,800 TT RS
by HENRY CATCHPOLE
PHOTOGRAPHY by ANDY MORGAN
tanding in one of the pit garages at Jarama Circuit, near Madrid – location for the launch of the new TT RS – there is a display of various engine parts for the latest Audi five-cylinder engine, demonstrating just how the company has cut 26kg from the unit’s weight (it saved 18kg with a new, aluminium crankcase). Behind it is a pictorial timeline taking the viewer through 40 years of Audi in-line fives.
‘I had one of those as my first car,’ says a voice behind me. It’s Stephan Reil, the amiable head of Quattro GmbH and therefore the man in charge of Audi’s RS models. He’s pointing at the Audi 100 way over on the left-hand side of the chronologically ordered photos. He tells me that although the engine was good, the three-speed auto gearbox it was attached to was terrible. Nonetheless, I can imagine how much the 18-year-old Reil would have appreciated having this impressive car to run around in, the quintet of pots doing just what Audi intended and lifting it above all the four-cylinders in status.
Mercedes actually put a five-cylinder engine into a production car two years before Audi, and Lancia had a five-cylinder engine in a truck back in the 1930s, but those were both diesels; Audi was the first to bring a petrol five-cylinder engine to market. The main reason that this configuration hadn’t been used before this was the difficulty of getting the fuel into the cylinders with carburettors. Use one carb and the outer cylinders would be much further away than the middle cylinders, meaning uneven fuelling. Use two carbs and things were equally tricky because one carb would be supplying three cylinders and the other only two. Diesel engines obviously don’t suffer from this issue as they have always used fuel injection, but it wasn’t until fuel injection in petrol cars became more widespread in the 1970s that the petrol five-cylinder became a more viable option.
Audi was looking at a five- or six-cylinder engine to take its cars upmarket and a six was deemed too bulky (plus the competition in Munich had rather made the straight-six its own). The new 2.1-litre naturally aspirated five-cylinder unit was based on the EA 827 four-cylinder (that had already appeared in the Audi 80 and Audi 100) and arrived in the Audi 100 5E in 1977, putting out 134bhp. A naturally aspirated diesel followed in 1978, but things really got interesting a year later when the first turbocharged five-cylinder petrol arrived.
With 168bhp and 195lb ft, the Audi 200 5T was initially the top model, but then came the Ur-Quattro. From here we have the line of legendary rally cars that everyone is familiar with, from the 300bhp car that Hannu Mikkola piloted to a win in Sweden in ’81 to the mighty Sport Quattro S1 (E2) that Walter Röhrl took up Pikes Peak in 1987. There were the racing cars, too, most notably the incredible IMSA GTO, which produced 710bhp from not much more than two litres.
On the road there was the wonderful RS2, but after that the five-cylinder largely faded from Audi’s line-up until 2009. In the interim there was, of course, the rather lovely Volvo/Ford in-line five, which kept the fire burning. When a five-cylinder re-emerged in an Audi, it did so under the bonnets of the TT RS, RS3 and RS Q3 and the engine has since gone on to win seven consecutive Engine of the Year awards.
But what makes a five-cylinder attractive to a manufacturer? Well, if there was a marketing department for fives, it would tell you that they are smoother than fours but not as bulky as sixes. Which is largely true. The reason a five is smoother than a four is all to do with secondary-order vibrations (feel free to skip to a couple of paragraphs at this point). A four-stroke engine fires all the cylinders once in every 720 degrees of rotation of the crank. In a four-cylinder engine that means four powerstrokes, and 720 divided by four equals 180, which means there is a powerstroke within every 180-degree rotation of the crank. A powerstroke can last no longer than 180 degrees, so if there is an even firing order, there can be no overlap between powerstrokes. Intuitively this sounds like something that should be balanced, but because the acceleration of a piston is greater at top-dead-centre than bottom-dead-centre, they don’t cancel each other out in the way you might expect.
Add an extra cylinder, though, and there is now a powerstroke every 144 degrees, meaning there’s overlap between the power phases. Basically the crank is always under load, so the engine runs more smoothly. There are still primary-order imbalances – those caused by forces that occur once per rotation of the crankshaft – but these are countered with weights on either end of the crankshaft. A firing order of 1-2-4-5-3 also produces the least primary imbalance, so is the one preferred in road cars.
Of course, the most common reason for people falling in love with the five-cylinder engine over the last 40 years is because of the sound. Whether it’s a Quattro ripping through a gravel stage or an RS2 starting up in the street, a five produces as distinctive a war cry as any engine, and Audi plays it to perfection. Apparently the sound can be represented by the musical interval 5:2, but that really is beyond my understanding.
Perhaps with all the downsizing of engines that is going on, we will see more five-cylinders appearing in performance cars. I certainly hope so, but I suspect whatever they appear in, the first instinct on hearing a five-cylinder burst into life will be to think it is an Audi. Anyway, now to find out what that latest, lightest five-cylinder turbo is like…
Left foot on the brake pedal. drive select mode to Dynamic, gearbox and ESP in Sport. You can probably guess what’s going to happen next. Press the throttle pedal all the way through the kickdown button to the carpet. Hear the revs rise and then settle at 3500rpm with a rapid-fire pulse reminiscent of a WRC car as the clock counts down at a stage start. Brace head against headrest. Sidestep the brake pedal.
Corks out of bottles, stabbed rats, Dennis the Menace’s catapult: all the usual similes apply as the TT RS launches itself from its coiled position on the start/finish straight at Jarama. There is the faintest scrap of wheelspin, just a few degrees of useless rotation on one, maybe two of the wheels, but otherwise all 354lb ft is deployed without fuss. And around three-and-a-half seconds later, the car is travelling at a mile a minute. The app that is loaded into the car actually registers a 0-100kph time of 3.4sec, which is astonishing. You might say that matching a Ferrari 458 is nothing unusual these days, with 911 Turbos popping out sub-three-second times with the regularity of a teenager posting on Instagram, but this is an Audi TT. Yes it’s the £52,000, top-of-the-range TT, but it’s a TT nonetheless.
For some, that sort of acceleration will be enough of a lure. But for others it’s almost an irrelevance if the car does nothing interesting in a corner. Later we’ll come back to the circuit that saw Gilles Villeneuve’s last victory, but for now we’re heading to the spectacular roads around the El Atazar Dam about an hour north of Madrid. The journey on the dual carriageway gives a chance to appreciate the very red but very beautifully appointed interior of our car. If you simply held the flat-bottomed steering wheel with its red start/stop button and looked through the upper portion at the virtual cockpit screen then you could be in an R8, such are the similarities. One thing that does need to go, however, is the gear selector, which looks at least ten years out of date. Audi will allow you to lose the fixed rear wing if you want (replacing it with an automatically extending item) and I spend some miles pondering whether this might give the TT RS the same attractively understated aggression as a 911 R.
When we’re off the slip road and heading towards the dam, the traffic disappears, as do all idle thoughts of rear-wing deletion. Press the exhaust button and the engine goes from unobtrusive to pleasingly present, though it wakes up automatically if you scroll from Comfort through Auto to Dynamic on the Driver Select modes. For the first time, switching to Dynamic also changes the way torque is shuffled around by the quattro system, with more impetus going to the rear.
If the TT RS felt fast executing a standing start, it arguably feels even faster point-to-point down a twisting piece of road. The steering isn’t brimming with feedback and I would even like a little more weight, but the accuracy of it inspires huge confidence. Likewise the grip that the RS displays just seems to encourage you to drive it harder and harder. After a ten-mile unbroken run, it’s hard to imagine what sort of car would have been able to stick with the relentless pace of the little Audi. A measure of just how hard the car has been driven comes from the smell and sound of the brakes, which despite having optional carbon-ceramic discs at the front, clamped by imposing eight-piston calipers, have started to wilt a little.
As an option you can also specify adjustable Magnetic Ride dampers, but I’d be more than happy to stick with the standard passive setup that’s on our test car. It doesn’t crash or jitter over imperfections at low speed, but rather retains a pleasing sense of travel. Just enough roll and pitch is retained to give the driver a satisfying sense of how the car is behaving, too.
The initial reaction of the front end as you turn into corners is better than any other TT that I can remember, no doubt helped by having less weight slung ahead of the front wheels. Equally impressive is the unwavering traction out of corners, which means you simply deploy maximum force on every exit. Ironically, as we near the dam, with its unfinished bridge jutting out like a prop from a film set, there’s a Nissan 200SX practising some drifting on a hairpin.
Perhaps surprisingly, you really need to keep on top of the RS’s engine. It sounds torquey low down, but it really needs to be above 4000rpm to provide the response that you expect. Luckily, the seven-speed dual-clutch S-tronic ’box makes life fairly easy in this regard, and although a manual would be nice, the efficiency of the paddleshift suits the character of the car.
And it’s a wilder character that the handling balance is really lacking. What happens between the turn-in phase and the acceleration phase of the corner is where the TT still feels frustratingly one-dimensional. Turn in hard with the brake-based torque vectoring assisting and there is a sense that the rear is beginning to edge round nicely, pointing the car tightly in towards the apex, but the car never allows this to blossom and always reverts to a nose-led attitude. Similarly, if you get on the power early in a corner you can feel the rear squat and you can sense a subtle balance change, but the chassis never allows you to really open the steering early or feel like the throttle is something you can change the angle of the car with.
Back at the circuit, the RS feels delightfully nimble through the more flowing corners, jinking lightly between the kerbs of the quick Ascari chicane and inspiring confidence through the fast Varzi right-hander. Mostly, however, it remains a paragon of speed through stability.
I actually enjoy the TT RS most when I’m not driving flat-out. For a start, when you’re not eking the last tenths from the tyres, you can more readily revel in the terrific sound from that five-cylinder (perhaps the TT RS Roadster is the one to have…). The deep warble that rises to something harder but still distinctive as it homes in on 7000rpm is a major reason to favour this car over a four-cylinder Cayman. The trouble is that the TT RS always feels bursting with energy, so you really want to drive it hard. And while it would certainly be wrong to blithely brand it with the ‘boring Audi understeer’ badge, it’s simply not as balanced and beguiling in the corners as the Porsche. I can’t help feeling that it’s tantalisingly close to being really engaging and that a proper torque-vectoring rear diff like the one in the Focus RS would help. If it could unlock the attitude that the TT RS so nearly has then it would turn it into a real hero car, like many of its five-cylinder ancestors.
Audi TT RS
Engine In-line 5-cyl, 2480cc, turbocharged CO2 189g/km
Power 394bhp @ 5850-7000rpm Torque 354lb ft @ 1700-5850rpm
Transmission Seven-speed dual-clutch, four-wheel drive, Torsen differential (rear), ESC
Front suspension MacPherson struts, coil springs, dampers, anti-roll bar
Rear suspension Four-link, coil springs, dampers, anti-roll bar
Brakes Ventilated carbon-ceramic front discs (option), 370mm, solid cast-iron rear discs, 310mm, ABS, EBD
Wheels 19in front and rear Tyres 245/35 R19 front and rear
Weight 1440kg Power-to-weight 272bhp/ton
0-62mph 3.7sec (claimed)
Top speed 155mph (limited; 174mph optional)
Basic price £51,800
On sale Now
evo rating: ★★★★☆
‘Things really got interesting
when the first turbocharged five‑cylinder arrived’
‘You might say that matching a Ferrari 458 is nothing unusual these days, but this is an Audi TT’
‘Get on the power early and you can feel the rear squat and a subtle change in balance’
'I actually enjoy the TT RS most when I’m not driving flat-out'