Andrew Frankel has been racing cars for over 20 years and testing them for nearer to 30. He is senior contributing writer to both Autocar and MotorSport magazines, sits on the Car of the Year jury and was chief car tester for the Sunday Times for 15 years. He cites driving and writing as the only disciplines for which he has any talent and therefore considers himself vocationally employed. When he is not working he lives quietly in the Wye Valley with his family, a small and unimportant accumulation of cheap old cars and some sheep.
Here’s a question. Which engine has the higher state of tune: the twin turbo V8 Ferrari fits into its brand new 488 GTB surface to surface missile, or the single turbo four under the bonnet of the new Peugeot 308 GTi? By now you’ll be thinking it’s the Peugeot because, after all, what possible profit would remain in this sentence were it not? But actually it’s the Ferrari, the point being that it is by only the tiniest amount. According to my calculator, the 3.9-litre engine in the 660bhp Ferrari gives 169bhp for each of those litres, while the 1.6-litre motor in the Peugeot offers 166bhp. And it’s in a higher state of tune than the engines fitted to the new McLaren 570S, the new Porsche 911 Turbo S and, of course, every normally aspirated engine on sale.
If it seems crazy to you that you can now buy an everyday 1.6-litre hatch with 266bhp, you’re not alone. I can remember thirty years ago buying a 205 GTi with the same sized engine and thinking its 105bhp was pretty racy which, of course it was.
My problem with these small capacity but ultra-high output motors today is that they just don’t deliver their power the way I would like.
Twenty four years ago Rover produced a car called the 220 Turbo Coupe, known today at the Tomcat. It has a 2-litre engine with 197bhp, which back then was pretty impressive if hardly unprecedented. But what the engineers were most proud of was its torque curve. Indeed they liked it so much, they gave it a name. They called it ‘Ayres Rock’ and when you saw said curve it was not hard to see why. Having chuntered along the desert floor for 1,000rpm from idle, the moment the turbo made its presence felt, the curve climbed almost vertically to 171lb ft where it took a ninety right and headed horizontally off into the distance. Using electronics to control the torque in this way allowed maximum access to maximum torque for the maximum period of time. You can see why they were pleased.
But almost a quarter of a century later the game has moved on. Or at least it should have done. In fact the torque curve of the 308 GTi follows a remarkably similar trajectory, hitting 243lb ft at just 1,900rpm and clinging there, limpet-like, all the way to 5,000rpm. And I’m not just pointing the finger at Peugeot: most high performance, small capacity petrol turbo motors do the same thing and the results, while undeniably effective, are a touch inelegant.
At a fundamental level, front-wheel drive exponents of this art are going to be traction limited, and when you overwhelm the front tyres of such a car with torque, torque steer results, no matter how clever your suspension and differentials. We saw it with the Ford Focus ST and we see it with this Peugeot. More subtly however, there’s no progression to the power, no sense of building to a crescendo. It’s just like opening a tap and letting the torque flood out.
Ferrari is starting to figure this out. The 488 GTB has an immense 553lb ft of torque but you can use all of it all the time in top gear alone. And that’s not down to some defect in engine or gearbox: it’s the way Ferrari wants it. Indeed its engine has a different electronic map not just for every mode from wet to sport to race, but also for all seven gears in its gearbox. Rather smartly Ferrari has twigged that controlling torque release in such a way that the higher the revs the more is supplied is precisely what’s required. The ultimate aim is to achieve the torque of a turbo with the response characteristics of a normally aspirated engine, and while there’s some distance to go, it’s well under way.
Why can Peugeot, Ford and all the others not do the same? I doubt it would be expensive and it would undoubtedly improve the quality of the torque delivery on offer. But might this be at the expense of ultimate performance potential? Possibly, but the key word here is potential: if you can’t use it all in the lower gears because it makes your steering tug and your tyres vaporise, there’s very little point having it.
So given that almost all fast cars in future will have turbos I’d like to see torque curves that don’t rocket upwards and then plateau, but rise gently throughout the rev range. Just like a really good high performance non-turbo engine, in fact.
Renault image courtesy of Neils de Wit licensed under CC BY 2.0