Are naturally aspirated engines losing their charm to turbos?

Turbo-petrol engines are rapidly finding their way into smaller, more affordable cars, promising stronger performance from smaller capacities. But as turbos rise, naturally aspirated engines face an interesting question.

Turbos are coming to smaller cars these days, and they are no longer knocking politely at the door, they are barging right in. From compact SUVs to family cars, turbo-petrol engines are becoming increasingly common, often sitting alongside naturally aspirated units. So, is the good old NA petrol engine slowly losing its mojo?

For decades, naturally aspirated engines were the bread and butter of affordable cars. They were simple, dependable and predictable, with a linear power delivery that made them easy to live with. not to forget that driven correctly, naturally aspirated engine provide phenomenal fuel economy as well. But times are changing. Cars are getting heavier, buyers want more performance and small NA engines can sometimes find themselves biting off more than they can chew.

Enter the turbo.

Turbos are moving down the ladder

Turbocharged engines were once largely the preserve of performance cars and premium models. Today, they have trickled down to much more affordable cars.

Take the Tata Punch, for example. Its naturally aspirated 1.2-litre petrol engine does the job for everyday driving, but more power has been one of the demands from buyers. Tata has now answered that call with a 1.2-litre turbo-petrol engine.

Renault has followed a similar route with the Triber. The 1.0-litre naturally aspirated engine keeps things simple, but the new 1.0-litre turbo-petrol gives the three-row MPV some much-needed extra muscle.

The trend is particularly clear in the sub-4-metre SUV space. The Tata Punch, Renault Kiger, Hyundai Venue and Kia Sonet are among the models that offer turbo-petrol engines alongside naturally aspirated options, depending on the model and variant.

In other words, the turbo is no longer the exotic ingredient on the menu. It is increasingly becoming part of the regular spread.

Why are turbos having a moment?

The answer boils down to one word: power.

A turbocharger forces more air into the engine, allowing it to produce more power and torque than a naturally aspirated engine of similar displacement. For the person behind the wheel, that usually means stronger acceleration, easier overtaking and less effort when the car is carrying a full load.

This is particularly useful in SUVs. A small NA engine can feel perfectly happy in a lightweight hatchback, but ask it to haul a larger SUV, five passengers and luggage up a hill, and it may start feeling like it has bitten off more than it can chew.

A turbo, meanwhile, gives the engine some extra breathing room.

Downsizing has become one of the biggest advantages of turbocharging, allowing manufacturers to shrink engine capacity without necessarily shrinking performance. A smaller turbocharged engine can deliver the sort of punch traditionally associated with a larger naturally aspirated unit, while also helping manufacturers improve fuel efficiency and reduce emissions. A 1.0-litre turbo, for instance, can produce power and torque figures that were once the preserve of 1.5-litre or even 1.6-litre naturally aspirated engines. The turbo effectively gives a small engine a bigger pair of lungs when the driver demands more, making downsizing a useful way for carmakers to balance performance, efficiency and increasingly stringent emission norms.

But there is no such thing as a free lunch

Turbos bring their own compromises.

The additional hardware makes the powertrain more complex, while turbo-petrol variants generally cost more than their naturally aspirated counterparts. There can also be differences in power delivery. Modern turbo engines have become much better at ironing out turbo lag, but they can still feel less linear than an NA engine due to the lag.

Fuel economy is another piece of the puzzle. A small turbo engine can be efficient when driven sensibly, but bury the accelerator regularly and the fuel gauge can start moving in the wrong direction rather quickly.

So, while the turbo may put a bigger smile on your face, it can also put a bigger dent in your wallet.

The NA engine still has plenty going for it

This is where the naturally aspirated engine refuses to throw in the towel.

Its biggest strengths are simplicity, affordability and predictable performance. With no turbocharger and associated forced-induction hardware, an NA engine has fewer components to complicate the equation.

Then there is the price advantage.

Naturally aspirated engines are generally cheaper, which is why they are often found in the lower variants of cars. And those variants can sell in significant numbers because not every buyer is looking for neck-snapping acceleration. For many, the priority is simple: get a reliable car, keep the purchase price under control and get from A to B without breaking the bank.

For such buyers, an NA engine can still be just the ticket.

But NA engines have one Achilles' heel

Performance.

A 1.0-litre or 1.2-litre naturally aspirated petrol can be perfectly adequate in a small hatchback. But put a NA engine in a heavier SUV and load it with passengers, and its limitations become harder to hide.

Highway overtaking may need more planning, while climbing steep roads can require more revs and patience. The engine isn't necessarily bad; it simply has less torque in reserve.

That is precisely where the turbo pulls away.

Is the NA engine losing its charm?

Not quite. But the writing is certainly on the wall when it comes to the growing popularity of turbo-petrol engines.

Turbos offer manufacturers a way to squeeze more performance out of smaller engines, while buyers get stronger acceleration and better flexibility. Naturally aspirated engines, meanwhile, continue to hold the fort at the more affordable end of the market.

So perhaps this isn't a case of turbo versus NA, with one destined to send the other packing.

Instead, the two are increasingly finding different jobs. The NA engine remains the sensible, affordable workhorse, while the turbo is becoming the more enticing option for buyers who want their small engine to punch above its weight.

The turbo may have stolen the limelight, but the naturally aspirated engine isn't ready to ride into the sunset just yet.

Subscribe to Auto Today Magazine

- Ends