Does Your Modern Sports Car Need a Turbo?

Why is it that modern production automobiles, whether they be oriented for the street or the track, are so often equipped with turbochargers? There are plenty of uses for turbochargers, and few of them better suited to the realm of diesel cars and trucks, but recently, it seems as if cars intended to go fast have been picking up the turbo and trying to push it forward. Does this come at a massive price? Are modern automakers savvy enough to make cars that are both turbocharged and totally involving? Is the insistence on fuel economy improvements valid? Taming the turbocharger and all its unruly power was done in the eighties and nineties, but now, the turbo serves as more of a political vehicle. The question is, should small-batch sports cars be subject to politics in the way the economy cars are?

Turbos came onto the forefront in the eighties when every car that aimed at going quickly had to have one. After a while, the word turbo became so ubiquitous that vacuum cleaners and hairdryers were sold with the word “turbo” adorning their bodies, and eventually the word became synonymous with power. While they were a step forward in many ways, cars of the nineties onward weren’t regularly turbocharged if they didn’t have to be. Japanese sports cars were confined by their gentleman’s agreements and some manufacturers were happy having a turbocharged car in their fleet – see the Porsche 911 Turbo, but atmospheric efficiency had moved on since the eighties and typically, worthwhile sports cars avoided the big snails.

The reason for this, and the crux of this argument is, turbochargers are not as effective as sometimes thought to be. While they might boast huge horsepower figures and relatively high mpg ratings, in subtle yet important ways, they detract from the driving experience. After all, driving is not just about going fast, but the immersion a driver feels inside the car. Is this less important than outright performance? After all, production cars need to be fun to drive, not merely a vehicle for delivering one-ups and boastful statistics in the bar.

Perhaps the most notable setback of turbocharged engines is the perceived delay, or lag. While the mark of a great sports car is instantaneous response from the pedal, turbo cars’ power output is subject to engine load, boost pressure, turbine speed, and a number of other factors that interfere with the interaction between man and machine. While the eons of turbo lag common in the eighties has been solved, it’s very difficult to get around even a minute delay in response with modern cars – even Ferrari’s modern 488 GTB and McLaren’s 650S have a minor amount of lag between depressing the throttle and the power surging in. Despite what manufacturers claim these days, lag simply can’t be avoided on the road. On track, high in the rev range, it’s not a huge problem, but when driving on the street, a momentary delay followed by a surge of power isn’t ideal.
Which brings us to the turbocharged engine’s second failing: power delivery. A normally-aspirated engine that sings smoothly and progressively through the rev range is something special to experience. With turbocharged engines, they tend to deliver power in a chunky fashion, which is not what one wants when threading the needle. A massive surge in the mid-range is the defining characteristic, sometimes followed by a slightly limp top-end. Modern automakers have tried to make their cars feel more “normally aspirated” by cutting torque at low revs and in the lower gears, and stapling in a top-end that doesn’t feel as exhilarating as one would find with Ferrari’s normally-aspirated predecessor to the 488: the 458 Speciale. Ultimately, that lumpy power delivery is hard to manage anywhere, but especially on the street with cambers, debris and pavement changes.

 

So why are manufacturers doing this? The most common reason in undoubtedly fuel economy. Auto manufacturers have to move towards reducing carbon emissions whether they want to or not, and to keep power levels reasonably high and C02 output low, the force-fed motor is seen to be the way forward. These engines produce more power than their normally-aspirated counterparts, but don’t burn as much fuel – supposedly. In reality, it’s much more complicated, and infuriating, when one starts delving into the details.

Testing a turbocharged car for emissions doesn’t quite tell the whole truth. When the car is smogged, it is always done so at appallingly low revs, and the turbocharger isn’t spooled up entirely. Therefore, the car doesn’t use boost to increase engine power and, effectively, capacity. A turbocharged engine is like a variable-displacement engine, and in keeping the turbo off-line, it produces the emissions of a smaller engine. There’s a problem with this approach that the least savvy environmentalist with an understanding of engines should see. After all, the aforementioned cars all boast more than 600 horsepower, and it’s not going to take a rocket scientist to figure that these machines usually won’t be driven around as if a geriatric with a bad hip was sitting shotgun.

 

No, the turbo sports cars of today will be driven hard, and often, these engines consume lots of fuel when their turbochargers are delivering all that boost. In real world tests, fuel gains aren’t all that impressive. To complicate issues, the immense heat a turbocharged engine produced is sometimes reduced by spitting a bit of extra fuel into the engine for cooling. With these concepts in mind, it seems ludicrous that small-batch sports cars are being subjected to the rules that better apply to large-scale commuter cars.

In summary, the turbocharged engine is less manageable, which means the driver is less involved and the experience is less rewarding than with an atmospheric engine. Though manufacturers have been able to refine the turbocharged engine’s power delivery, it will never be as responsive, progressive, and visceral as a normally-aspirated engine can be. Additionally, the sound is muffled somewhat by the turbo recycling exhaust gases. In terms of sheer drama, the turbocharged engine is beat hands-down.

Compounding this harsh reality, the fuel gains aren’t as simple as they’re announced. Seeing as the turbocharged sports cars are seldom going to be driven gingerly enough to get those economy ratings, why mess with the formula in the first place? After all, the number of cars that Ferrari and Porsche sell are a drop in the bucket compared to economy cars and trucks designed exclusively to pick up the groceries and take the kids to soccer practice, and sports cars’ contribution to greenhouse gasses is if not negligible, very minor. Without a doubt, the commuter cars of the world should employ whatever helps them get a little better economy, but for the quicker machines, leave them be: they, their drivers, and the environment are better off without forced induction.