Which Audi Q5 is better: diesel or petrol?

Join us as we decide which Audi Q5 is best, the petrol or diesel.

In its first generation, the Audi Q5 was available with various petrol- and diesel engines. You could even get one with the Volkswagen Group’s brilliant 3.0 V6 TDI, and some markets also received a supercharged 3.0-litre V6 petrol version. But, with the arrival of the current generation in mid-2017, the range was trimmed down to a pair of 2.0-litre turbo engines in either petrol- or diesel flavours. We look at the two engine options to choose the best one.

It’s all about the numbers

Getting used to Audi’s current model designations isn’t easy. Gone are the days when “2.0 TDI” meant a 2.0-litre turbodiesel and “3.2” meant a V6 engine. No, this premium manufacturer decided to move to a “placeholder” format, with seemingly random two-digit numbers to denote a specific band of power outputs. It starts at “30”, meaning the 80- to 95 kW range, and runs all the way up to “70”, indicating outputs of more than 390 kW. The car’s fuel requirement is then indicated with either a “TDI” for diesel or “TFSI” for petrol (all turbocharged).

At the time of writing, Audi had removed the petrol-powered Q5 models from its range, but we will still use the 45TFSI for the sake of comparison. Where does this leave the two engines in the Q5 range, with the 40TDI and 45TFSI? According to Audi, “40” means “somewhere between 125 kW and 150 kW”, and “45” means “169 kW to 185 kW”. It’s a strangely lumpen and rather confusing naming convention, but probably unavoidable in an era when turbo 2.0-litres produce more power than yesteryear’s V8s.

The current Q5 range

We will compare the 40TDI and 45TFSI 4-cylinder turbocharged engines, with both the diesel and petrol featuring Audi’s full-time quattro all-wheel drive and an 8-speed ZF automatic gearbox. Let’s take a closer look at the key figures:

* Manufacturer’s claimed figures for performance and average fuel consumption.

** Petrol Q5 models have been discontinued, and the only petrol-powered Q5 variant is the performance-oriented SQ5. The price quoted was valid in early 2022.

Which engine is right for you?

Right from the outset, it’s clear that the more expensive Q5 45TFSI holds a significant performance advantage over the 40TDI – as it should be, given the 45’s elevated position in the range hierarchy. It enjoys a 45-kW advantage over the TDI’s 140kW, and while it’s slightly down on torque, the petrol engine’s wider operating range and stronger top-end power give it a decisive win on both acceleration and top speed.

However, according to the official claimed consumption figures, the Q5 40TDI is considerably less thirsty. Its claimed average of 4.9 L/100 km might be a little far-fetched in normal driving, but sub-6 L/100 km average consumption should be easily attainable by moderately conservative drivers, especially if some open-freeway cruising is thrown into the mix.

In contrast, the Q5 45TFSI demands to be fed more regularly, and Audi claims it should return 6.8 L/100 km in a combined cycle. It’s doubtful that the petrol Q5 will achieve even this figure on real roads, however, where low-8 L/100 km will likely be the best it can do: the Volkswagen Group’s EA888 2.0-litre engine family is known for being fairly profligate drinkers when working hard. Add the Q5’s hefty kerb weight (1800 kg or more) and frictional losses from the AWD system to the equation, and it becomes clear that the 45TFSI isn’t the optimal engine from a consumption perspective.

The Verdict

It all comes down to a choice between performance and fuel consumption: the Q5 range doesn’t really offer a middle ground between these extremes. That said, the Q5 40TDI has enough performance on tap to hold its own in traffic, and its torque advantage will make it the better choice for towing or hauling a full load of passengers. It will also be considerably less thirsty on long road trips. For this balance of adequate performance and excellent efficiency, the Q5 40 TDI has to be the best choice in the range.

Keyword: Which Audi Q5 is better: diesel or petrol?