Motor Mercedes AMG GT, Test stand, Glowing turbo charger 38 Photos Zoom

Commentary by Marcus Schurig: Turbo engines - rescue or downfall?

sport auto Chief Editor Marcus Schurig on the heated debate regarding the spread of turbo like wildfire in sports cars - and how a trip back in time can explain what we will lose and why.

The telephone has been annoying recently. Holger, a mate from past Nordschleife days, wanted to say hello and inform me that he had finally bought his dream car. Although to say it was not enough, and so I had to call round. When I arrived, it was a great pleasure to meet with two old acquaintances: the friend himselg – and his newly acquired 2001 Audi RS4 (B5).

Avus silver metallic paint, Quattro sports exhaust, bucket seats, 140,000 kilometres on the clock, but with a new engine and overhauled transmission, one of the 6,030 successors to the cult RS2. "It goes like the clappers", promised Holger. Naturally, for with a touch of tuning, it posts a value of 440 horses on the data sheet. "Get the key out at once!"

Rummaging about in turbo memories

It was a - wonderful - journey into the autohad almost the exact same care as an endurance test vehicle. The 2.7-litre V6 biturbo was a hellraiser with it own unique, enticing acoustics, the sound of which one never forgets. In any case, the 20-minute test drive certainly brought a grin to my face – and made me wonder. Why did I find turbo engines so great back then, and why am I less enthused by them today, even though they are much better? I first had a rummage around in my fonder turbo memories.

The list included (without by any means claiming to be complete): Ferrari F40. Audi S1. Lancia Delta Integrale. RS2. RS4. Then it gets tricky, the Rally gods: the Subaru Impreza and Mitsubishi Lancer Evo VI. Somewhere around here the charging pressure of my turbo euphoria dropped somewhat, and with difficulty I turn to the modern era– the Nissan GT-R and Audi TT RS. To paraphrase: V8 biturbo; V6 biturbo; five-cylinder turbo; four-cylinder turbo. So colourful! The deciding factor: there were also many alternatives, whether naturally aspirated (M3, GT3) or wild compressor engines (Corvette ZR1).

The naturally aspirated engine makes the turbo seem great

That is to say: it is the lack of variety, that creates the desire for turbo, and for two reasons: first of all the ubiquitous compulsory ventilation, since the naturally aspirated engine, as is repeatedly explained to us, is dead, thanks to the NEFZ cycle. The turbo becomes cool when I step out of the naturally aspirated car – and the reverse also applies, and so too is the case with the compressor.

BMW M GmbH previously relied on high-speed naturally aspirated engines, AMG on compressors and Audi – as is the case in the RS4 – on turbo. All three variations were great – precisely because all three existed. Secondly, the turbo segment is lacking this variety, aside from a few exceptions (Audi TT RS or Nissan GT-R). The turbo engines in sports cars are often all-round plough horses, which ascend from lowly service vehicles and are then used as sports engines,with sound-generators.

The reason: the costs and that annoying NEFZ cycle. However, every sports driver known: in actual fact, a turbo engine always guzzles more fuel than a naturally aspirated engine, when the driver puts his foot down. The sales pitch is also a lie. Worst of all is the ubiquitous V8 turbo plague, the pandemic monotony at Mercedes, Audi and BMW, which is gradually spilling over into the sports car segment.

Turbos can be great, but...

The faith in progress on the part of sports car drivers is thoroughly being put to the test. Turbo engines may be the rescue for manufacturers, but for sports cars, as a monocausal drive system, they are a pain in the neck. Sports car engines are changing, and are moving in a direction that has nothing to do with driving fast.

Exogenous factors are driving development, and not the goal of travelling fast(er) or better. The turbo is not the better sports engine. Turbos can be awesome – but not if turbos were all that there was, all sounding the same, driving the same and with the same number of cylinders. The Audi RS4 owned by my pal Holger has left a glorious future behind – for Holger won't ever be willing to part with it.

Marcus Schurig, Chefredakteur sport auto





24 May 2015
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