Audi are set to release a new A3 with a petrol engine that could match the equivalent diesel for CO2 emissions. Could it transform the buying habits of fleet customers and have a knock-on effect on the second-hand market?

Audi A3

Spot the difference. It's no accident that the 3rd generation of Audi A3 looks much like the 2nd.

The engine in question is a turbocharged 1.4-litre that features cylinder deactivation technology. This was first demonstrated by Volkswagen on their Polo BlueGT model, an attractive combination of economy and performance, and in A3 trim the engine produces an official reading of just 106g/km. That’s roughly the same as the 148bhp 2.0 TDI model, although the petrol engine is slightly down on power with 138bhp.

The petrol can’t quite match the diesel’s economy either, with an expected average of 61mpg against the diesel’s 68mpg, but don’t forget that petrol is currently a few pence cheaper than diesel per litre. What the petrol engined car is likely to offer is a more refined driving experience.

What this could mean is that a lot of company car buyers will start switching back to petrol to avoid the additional tax they pay on diesel-engined cars. It will be interesting to see if such a shift happens and what effects it will have on the used car market. Will diesel-powered cars go up in value as supply is reduced, or will they become less sought after as people switch back to petrol as the cost savings of diesel disappear?

The Audi A3 is an important car in other respects. It is the first car to use the new MQB platform, Volkswagen’s new platform-sharing technology that will eventually underpin the vast majority of their cars, including Skoda and SEAT. The new platform makes it easier to share components, including a range of new engines, and brings with it a number of weight-saving measures. The use of stonger steel and other weight trimming means that the 1.4-litre A3 is expected to tip the scales at around 1,100kg, making it almost as light as the original model.

Don’t forget that this will eventually affect a lot of hot hatches. Volkswagen GTI, SEAT Cupra, Skoda vRS and Audi RS badges all stand to benefit from this technology. Cylinder deactivation could mean lower fuel bills without sacrificing performance and the lighter underpinnings could lead to improved driving dynamics, and that has to be a good thing.