Why does the Audi A1 have a smaller engine than other models?

I noticed that the Audi A1 has a 1.0-litre engine, whereas other models have larger engines. Is there a specific reason for this and how does it affect the car's performance?

The Audi A1 is designed to be more compact and fuel-efficient. The smaller engine size allows for better fuel economy and a lighter overall weight for better handling.

While the Audi A1 may have a smaller engine, it still packs a punch with its turbocharged technology. This means you can get the same power and performance as a larger engine, but with better fuel efficiency.