Audi’s new logical (but opaque) nomenclature

Previously, when most engines were normally aspirated and the vast majority ran on petrol, displacement was a simple way of establishing a clear model hierarchy. Even the most casual observer would understand that a 2.0 litre car was inherently superior to its 1.6 litre counterpart, for example.

Things are more complicated nowadays. Different fuel types, widespread turbocharger use and increased availability of hybrid technologies mean that size is no longer key when determining output.

Consequently, the decision by Audi to stop displaying engine capacity designations on its vehicles seems sensible enough. Less well thought out is the new numbering system that'll be appearing instead.

Rather than adopting something straightforward (such as horsepower), two-digit identifiers are going to signify performance levels according to these kilowatt bands:

• 30 – 81-96 kW (108-128 bhp / 110-130 PS)
• 35 – 110-120 kW (147-160 bhp / 150-163 PS)
• 40 – 125-150 kW (167-201 bhp / 170-204 PS)
• 45 – 169-185 kW (226-248 bhp / 230-251 PS)
• 50 – 210-230 kW (281-308 bhp / 285-312 PS)
• 55 – 245-275 kW (328-368 bhp / 333-373 PS)
• 60 – 320-340 kW (429-455 bhp / 435-462 PS)
• 70 – 400+ kW (536+ bhp / 543+ PS)

So, because the next-generation A8 with a 3.0 litre petrol engine has 250 kW, it's being called A8 55 TFSI. Likewise, the 3.0 litre diesel version with 210 kW is getting the A8 50 TDI moniker.

All very rational, but there are two obvious flaws. Firstly, the aforementioned 'casual observer' (and indeed many prospective customers) might be confused into thinking that an A8 55 TFSI has a 5.5 litre engine. Secondly, the gaps between each tier are odd. What happens if a particular car produces 100 kW, or 160 kW, or 300 kW?

Introduction of the revised nomenclature is due to commence later this year. All S and RS variants, plus the Audi R8, are exempt.