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Engine Downsizing Trend: Balancing Pros and Cons

Will engine downsizing work? Well, there is no definitive answer to that since there are many factors to look at.

Ntsako Mthethwa
December 12, 2023
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In the ever-evolving landscape of the automotive industry, there has been a fair share of trends that have come and gone, while some endure and evolve into industry standards. 

For example, the fourth generation of the Honda Inspire was the first to introduce lane-keeping assistance in 2003, marking the beginning of a safety revolution. Since then, almost all manufacturers have adopted the technology and developed their own version of the system with different features and capabilities. 

However, not all automotive trends are greeted with equal success. If you recall, in 2012, Fiat introduced an espresso maker in its 500L, and it was a complete blunder as most people preferred other ways of getting their drink. This brings us to the topic at hand: the engine downsizing trend, which has been a serious topic in most boardrooms as tighter emission regulations as well as improved efficiency considerations become more prevalent. But what does it entail? 

As its name suggests, engine downsizing involves the use of smaller engines in vehicles with the same or higher power outputs derived from larger engines to improve efficiency, reduce emissions, and comply with tighter environmental regulations. Several features, including electrification, supercharging, and turbocharging, can be used to enable the technology. Mercedes-Benz, BMW, Ford, Audi, Porsche, Renault, and VW, to name a few, have done it in recent years. For some, it worked, and for some, it didn’t. 

Like most inventions in the motoring industry, engine downsizing has its own advantages and disadvantages, and we take a look at the pros and cons of the trend.

Advantages of Engine Downsizing

As a practise that was implemented in the olden days, the main reason for engine downsizing is to meet tighter emission restrictions and use smaller engines with the same or more power outputs, as the larger ones mean less fuel is burned and less CO2 is produced. 

For example, Mercedes-AMG is the latest marque to downsize its C63 engine, from the brutal 4.0-litre Bi-Turbo V8 engine to the mild-hybrid 2.0-litre M139 4-cylinder turbo-petrol unit that is shared amongst other AMGs in the range. This was done to comply with the stricter emissions, lower fuel economy, and CO2 emissions, as well as optimise the driving dynamics and handling of the C63 due to its lighter weight. 

Besides the aforementioned attributes, engine downsizing is also said to bring lower costs and higher reliability. How? You wonder. Well, a smaller engine normally has fewer parts and components, which reduces manufacturing and maintenance costs. Another important factor is weight reduction. Compact engines are lighter, which significantly lowers the overall weight of the car, and as you’ve guessed, this translates to better handling, agility, and performance. 

Smaller engines are also better suited for hybrid and electric adaptability due to their tiny nature. Because of their smaller size, hybrid or electric components can be installed in a more convenient location. This is a crucial consideration for integrating these components seamlessly into the vehicle's design.

As for manufacturers that have successfully followed the downsizing trend, BMW did it with its Twin-Power turbocharged engines that are used across its range, including the 3 and 5 Series models, and have been praised for delivering strong performance and superb efficiency. 

Volkswagen has also done it with its TSI engines which offer improved fuel consumption and reduced emissions without sacrificing performance. 

Even now, in 2023, it continues to surprise us how manufacturers are able to extract so much power from a small engine. 

Disadvantages of Engine Downsizing

While manufacturers cannot escape the reality of engine downsizing, it’s not a simple or straightforward solution but a trade-off that requires great levels of engineering and optimisation.

However, it has its own drawbacks, such as reliability and longevity, and they tend to perform worse in real-world driving emission tests than normal engines while also negatively impacting driving pleasure and comfort. One disadvantage of engine downsizing is that it can lead to decreased durability and reliability over time due to increased stress on the smaller engine.

Those with good memories may recall when Mercedes-Benz wanted to discontinue its naturally aspirated V8 engines in favour of the turbocharged V6. That move never materialised due to the engines failing to deliver on their emission promises, and they were not as enjoyable as the mighty V8s. Porsche, on the other hand, also went the same route with its 718 Boxster and Cayman in 2016. It traded the previous model’s naturally aspirated 2.7-litre and 3.4-litre flat-six engines for smaller 2.0-litre and 2.5-litre flat-four engines which obviously had more oomph and torque but also more lag, and they were criticised by many for being less emotive. Wait, there’s more. The engines lacked the character to suit the sporty nature of the cars while also sounding muted and lacking the emotional appeal of the old ones. 

Mercedes-AMG has been dominating the news since it announced that its C63 and C43, among others, under the AMG banner will be ditching the 4.0-litre V8 and 3.0-litre V6 engines for a much smaller but electrified M139 2.0-litre turbocharged petrol unit. 

Sometimes less is more, but in this case, I'm sure that many will agree that the setup isn’t best-suited for this application, and as far as we know, enthusiasts aren’t having any of that. The C43, for instance, isn’t what it used to be, despite having more power than before. Instead, the C43 is less charismatic, and it’s heavy at 1,840kg versus its forebear’s 1,690 kg which, as you know, a car's weight is its greatest enemy. 

Will engine downsizing work? Well, there is no definitive answer to that since there are many factors to look at, including customer preferences. Think about it: the automotive field is massive and diverse, and not all manufacturers have found their way around this intricate trend. These manufacturers may face challenges with the downsizing trend and need to reassess the technology to achieve an optimal balance between efficiency, power, reliability, and comfort.

On the other hand, some have found their rhythm, and they are now reaping the rewards of improved efficiency and reduced emissions while offering customers unmatched levels of driver engagement. The opportunities for electrification then remain ample, as long as weight continues to see its own downsizing trend. 

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