GREEN SPECIAL: Look how far we've come with fuel economy
Search Driven for vehicles for sale
We’re always talking about new technology improving the environmental credentials of the vehicle fleet, but it’s easy to forget (and appreciate) just how far we’ve come in improving existing tech. And how much of that work is continuing.
While the industry is accelerating as fast as it can towards BEVs and other future-proofed powertrains, it’s also true that petrol and diesel cars will be a big part of the fleet for decades to come.
A transition to new fuels will take time and you can’t just consider the new-car market; even if 100 per cent of new vehicles sold were BEVs starting from tomorrow, we would still have Internal Combustion Engine (ICE) cars on the road for decades to come due to the “rate of churn” – the time it takes for a vehicle to pass through several owners and come to the end of its useful life.
It’s enlightening to compare the fuel economy of cars of today with their equivalents from the past. And even when that past is not very distant, it’s clear just how far we’ve come thanks to technology like turbocharging, direct injection, cylinder shut-off – and even mild hybridisation, which is now becoming more prolific.
Let’s compare a couple of modern cars with their predecessors from 20 years ago. The Audi A4 40 TFSI is a nicely balanced sedan with a 2.0-litre turbo engine making 140kW/320Nm. It returns 6.0 litres per 100km - impressive for an executive car with that level of performance.
Rewind two decades and to match the 40 TFSI’s power in a 2000-era A4 you’d need the 2.6 V8 30v DOHC model – pretty high-tech itself at the time, making 142kW/280Nm. It epitomised Audi’s “Vorsprung Durch Technik” philosophy of the time. Combined fuel economy: 11.8l/100km, and that was from a test not as stringent as the latest WLTP cycle applied to the 2020 40 TFSI. The newer car has essentially managed to halve the fuel consumption figure.
Even when performance is absolutely the top priority, modern vehicles are providing much greater dynamic ability with no increase in fuel burn – and often less.
The RS6 is a true hero car of the Audi Sport range. Its 4.0-litre twin-turbo V8 makes a monstrous 441kW/800Nm and the car can accelerate to 100kmh in just 3.6 seconds. Official fuel consumption: 11.7l/100km.
The original RS6 was equally exciting back in 2002, but it hardly compares to its modern equivalent through a 2020 lens. The C5-generation RS6 made 331kW/580Nm and could hit 100km/h in 4.6 seconds. Fuel consumption: 14.6l/100km.
So the gap in fuel efficiency is not as great as it is in the more mainstream A4. But consider how much more the technology delivers: it’s 30 per cent faster, while still being 20 per cent more economical.
The next step from the mild hybridisation of cars like RS6 and RSQ8 will come with the new breed of 100 per cent electric sport models. The likes of the e-tron S with 380kW/973Nm or the new range-topping e-tron GT (0-100km/h 3.5sec) will make for truly green high performance.