Report: Audi five-cylinder lives on

EVER-TIGHTENING emissions regulations have threatened to doom Audi's in-line five-cylinder engine since the introduction of the Euro 6 standard in 2014, but a report by United Stated-based publication Car and Driver suggests the unit has another generation in it yet.

According to the report, the new engine will retain the basic format of a single turbocharger boosting a displacement of 2.5 litres, but “shares virtually nothing with the current 2.5-litre”.

The report mentions no specific technical details of the replacement five-pot, but GoAuto understands that Audi's engineers have made the significant step of transitioning the iconic engine from a cast-iron block to a more modern alloy construction.

With an all-alloy build, Audi's next-gen five-cylinder unit will be the start of a new era for the unorthodox donk, ending 36 years of iron five-cylinders and saving a significant amount of weight over the dated version.

The complete ground-up design is also expected to significantly cut emissions and increase fuel economy, while retaining the unique characteristics of five-cylinder power and the associated soundtrack.

A “highly reliable source” told Car and Driver that the new engine would first appear under the bonnet of the next-gen Audi TT RS at the Beijing motor show later this month, but would be followed by the sedan version of the hyper RS3 Sportback.

Neither RS variant of the current-gen TT sportscar or A3 small sedan have been officially confirmed at this stage, but Audi Australia has previously told GoAuto an RS version of the TT would be a “no brainer”.

With the warm reception of the A3 range and its hotter S3 and RS3 variants, it it likely the car-maker would apply a similar enthusiasm for the RS3 sedan.

With the arrival of the alloy five-cylinder engine in the forthcoming sedan, the current RS3 Sportback will be the final Audi to be powered by the CZGB-codenamed iron five-pot block, which has been tuned up to 270kW and 465Nm.

A mighty sedan version of the RS3 should come as no surprise given that the German car-maker rolled out a booted A3 concept dubbed the A3 Clubsport in 2014, which packed a 386kW/600Nm five-cylinder punch.

Despite its 'conceptual' status, the car was exhibited in driving form and could crack 100km/h from standstill in 3.6 seconds and a top speed of 310km/h.

That car used a highly-strung version of the previous-generation Audi TT RS' five-pot cast-iron engine, so it is likely an all new 2.5-litre version would easily improve on the standard engine's current high-score.

Mercedes-Benz holds the title for the most potent hatchback with its 280kW A45 AMG and corresponding CLA45 sedan, but a fresh five from Audi threatens to snatch the crown from its arch rival.

The swan song five-cylinder unit uses vermicular graphite cast-iron construction with additional reinforcement on main bearing seats and covers to allow a greater loading of the crankshaft from increased boost pressures, and allowed the use of relatively narrow main bearings.