Audi five-cylinder 45 years: why Audi sticks to it

Are we seeing it right, 12453? Can we no longer count or is there a secret code that the editors have overlooked? None of that: it is the firing order of Audi’s five-cylinder, which has been invariably screwed into compact RS models since 2009. That is special, if only because every relatively large petrol engine today is. If the combustion engine disappears from the scene for good, it will undoubtedly do so in the form of a four-cylinder. Even expensive performance models increasingly simply have a four-cylinder engine under the hood, whether or not in combination with an electric motor. The future Mercedes-AMG C63 even exchanges its V8 for a hybrid powertrain with a four-cylinder, but in the lower segments that engine form has been the highest attainable for a long time. Audi’s 2.5 is the only exception to that rule for compact hatchbacks. Because an older model is on its last legs? That may be the case in the case of the TT RS, but in the meantime Audi is casually pushing a completely new edition of the RS3, still boosted by the five-cylinder, into the showrooms. With 400 hp and 500 Nm, the latest generation of the block is powerful, but that is not unique. The only direct competitor of the RS3, the Mercedes-AMG 45 S, is even more powerful with 421 hp and the same number in newton meters, and that with a two-liter four-cylinder on board. That leaves the question: what should Audi do with that five-cylinder?

Nostalgia

Audi’s tenacity is remarkable, because in other areas the brand proves to be quite accommodating when it comes to cutting. Just look at what happened to the S6, which descended from a delicious V10 to a six-cylinder diesel in seven years. Then the step from an expensive five-cylinder that can only be used for niche products to a much more widely applicable four-cylinder seems more logical and less drastic in all respects. However, Audi does not want to do that for the time being. The official reason for the usually so business-like brand is surprising: nostalgia. During the 45th anniversary of the Audi five-cylinder, the brand states that it feels so connected with no engine type. The five-cylinder engine is part of what is so beautifully called the brand DNA, as are, for example, the single-frame grille and quattro four-wheel drive. That is quite difficult, at a time when the emphasis is increasingly on aspects other than the engine due to the emergence of electric cars.

That is why Audi pulls out all the stops as long as it can. Where the five-cylinder used to be primarily a way to achieve better performance, the unique sound and character of the engine are now celebrated. Rightly so, because the characteristic five-cylinder block has become a unique experience in the car world.

Audi 100

Audi is not the inventor of the five-cylinder, because competitor Mercedes-Benz is slightly earlier in 1974. However, that is a diesel, so Audi can rely on the fact that it has brought the petrol-fired five-cylinder to the market. And with success, it must be said. The first step is careful. For the C2 generation of the 100 presented in 1976, a six-cylinder was too heavy and a four-cylinder for the top model a bit too light. The logical consequence is the not previously used intermediate step, based on an existing four-cylinder. The 2.1-liter injection engine initially produces 136 hp, but from 1979 the engine reaches 170 hp in the more luxurious 200 thanks to a turbo. In the meantime, there will be a smaller version and a diesel will follow, an atmospheric one with 70 hp. Not much by today’s standards, but the two-liter is only 10 hp short compared to the much larger five-cylinder Mercedes.

Glory days

With the start of a new decade, the heyday of Audi’s five-cylinder also begins. The year 1980 brings the Audi Quattro, which, in addition to the revolutionary four-wheel drive, is always equipped with a five-cylinder. The ‘Ur-quattro’ is in fact the sporty brother of the Audi Coupé, the coupé version of the 90, the thicker brother of the 80. In terms of names, the Audi range was a mess at the time, but the Quattro is the undisputed king of the couple. With 200 hp, the original street version of the Quattro is already seriously smooth, but in rallying all limits are overboard. As the decade progresses, not only does the WRC-Audi’s appearance become more extreme, but so does the powertrain. The Group B regulations limit the displacement, but not the engine power, so the Audi power unit is pushed to impossible heights. Audi’s 2.1 already delivers 304 hp in the early days of the sports career. While the Audi Quattro gets wider and shorter, the five-cylinder, so modest in size, grows into a monster, with powers that are downright bizarre even by contemporary standards, in the WRC with powers of up to 500 hp. Walter Röhrl even drives to victory at the 1987 Pikes Peak Hill Climb with an incredible 598 horsepower.

Audi Quattro

Is that the highest achievable? No, because Audi also registered in 1989 for the GT championship of the American International Motor Sports Association, the IMSA GTO class. The participating and regularly winning Audi 90 Quattro IMSA GTO is the absolute top for the five-cylinder when it comes to pure performance and delivers 720 hp and 720 Nm, from a displacement of only 2.2 liters.

On the street it is logically a little more modest, because here the engine must also remain intact. The IMSA racer is based on the completely new generation of the 90, the more luxurious brother of the third generation of the 80 launched in 1986. Like its much more square predecessor, the new 80 series produces a coupé variant, but a car with the model name Quattro does not return. Instead, Audi is launching the S2, the first model under the S label. The S2 is also available as a sedan and Avant and delivers a neat 100 hp per liter with 220 hp. However, this model generation also receives the honor of the first RS model, the RS2 developed in collaboration with Porsche. The über-80 delivered purely as an Avant also gets a 2.2-liter five-cylinder, but with 315 hp. Audi is once again making history with its five-cylinder, because the RS2 can be seen as the ancestor of the fast station wagon.

Audi RS2

TDI diesel engines

With the S2, RS2 and the larger S4, we can also say that Audi’s sporty range originates from models with the famous five-cylinder, although that relationship is immediately over after that. The S2 and S4 dry up as S4 and S6 respectively and quickly switch to V6 and V8 engines as sporty brothers of the A4 and A6. The petrol-fired five-burner also disappears from the picture in the rest of the range as soon as Audi starts using type designations with an ‘A’. However, the diesel continues to steam for a while. In 1989 it is a five-cylinder that can call itself the first TDI, a 2.5-liter in the last edition of the Audi 100. The self-igniter developed entirely by Audi will later also be used in a whole series of Volkswagen vans and even in a number of models from Volvo, starting its own five-cylinder chapter in 1991. In addition to their own petrol engine, the Swedes install a version of Audi’s diesel 2.5 in successively the 850, S70 and V70 and even the S80, to eventually replace it with the D5 diesel developed in-house. The Swedes last so longer with this block than Audi itself, that the five-cylinder in 1997 in all forms from the range deletes.

Over and out? No, that was already clear. The five-cylinder engine made its glorious comeback in 2009, in the first edition of the Audi TT RS. You could consider the TT as a compact coupé (and roadster) as the spiritual successor of the old Coupé (capital letter) and Quattro, so that choice is not that crazy. It is strange, or at least remarkable, that Audi is apparently developing a completely new block for this model. Apart from the magical cylinder number, the modern TFSI with 340 hp has nothing to do with the Audi five-cylinder engines of yesteryear and is also placed transversely in the Audi nose for the first time.

However, this block turns out not to be completely new, because Volkswagen is already using an atmospheric version of the 2.5 in North America in, among other things, the Rabbit (Golf) and Jetta. We can be grateful to the American branch of the brand for that, because the EA855 is still built in compact RS-Audis in a firmly adapted form. The engine won the ‘International Engine of the Year’ award in its category five times in a row from 2010 to 2014 and, in its latest guise, delivers even more torque than before. The power is released in copious waves and the sound is, despite all kinds of emissions-related restrictions, more natural and ‘real’ than what four-cylinder alternatives usually deliver.

Audi RS3

Glory days

Fortunately, there is no indication that this pleasure is coming to an end any time soon. In addition to the TT and RS3, the engine in question is also housed in the RS Q3, which as a compact SUV is completely made for this time in all other respects. With two fresh, current models, it is almost certain that the power source will see Abraham.

By then it will be 2026, well before the sale of petrol and diesel cars is definitively banned under an EU proposal. Still, cars will have to emit 15 percent less on average in that year than now, and that while the new RS3 already exceeds the 2021 standard of 95 grams per kilometer by more than 100 percent. For the five-burner, the glory days are undoubtedly in the past, but the party is not quite over yet.