More Might From Audi’s TDI Titan

Audi has gifted even more muscle to its mighty SQ5 TDI diesel powerplant that now boasts 337bhp and claiming a 0-60mph sprint in just 5 seconds.

In its latest incarnation, the 3.0-liter V6 motor also delivers 516.3ft-lbs of torque across a wider engine speed range between 1,750 rpm and 3,250 rpm. Peak power is also produced earlier than before and an actuator in the exhaust system gives the V6 a sporty sound.
Numerous detail enhancements have been made including the original aluminum pistons have been replaced with stronger, lighter forged steel equivalents that both reduce heat losses and promote faster combustion thanks to new stepped recesses. The solenoid fuel injectors operate with a new piezo sensor that monitors the closing of the needle and allows up to eight injections per work cycle, with injection quantities that are scalable with even greater precision. The maximum injection pressure is 2,500 bar.

The direct air/air intercooler that was originally located in the bumper has been replaced by an indirect water/air cooler in the inside V of the engine. The shortened intake air paths help to build up boost pressure quickly. The indirect intercooler is more effective and can even heat the intake air shortly after the engine is started in cold ambient conditions in order to reach the ideal combustion temperatures more quickly. This means that the exhaust gas cleaning system can respond more quickly reducing emissions.

The turbocharger now features a smaller and lighter compressor wheel that spools up quicker while the exhaust manifold also benefits from improved insulation, enabling the exhaust gas to reach the optimum temperature more quickly after a cold start.

The combustion engine is augmented by an improved 48-volt mild hybrid system (MHEV) and electrically powered compressor (EPC). The MHEV integrates a belt alternator starter (BAS), a lithium-ion battery that provides buffer storage and a 48/12-volt voltage converter. When the car decelerates, the MHEV system recovers up to 8 kW of power. It also enables the SUV to coast for up to 40 seconds with the engine switched off, after which time it is restarted by the BAS. The system has the potential to reduce fuel consumption by up to 0.7 liters for every 62 miles driven.

The EPC intervenes whenever the exhaust gas flow provides too little energy to drive the turbocharger. A compact electric motor, which also uses the compact 48-volt system, accelerates the compressor wheel of the EPC to 65,000 rpm in roughly 300 milliseconds. In the latest generation SQ5 TDI the EPC is now used more frequently and across a broader engine map and is felt particularly strong during step-off acceleration and when pulling away from low engine speeds. Audi claims its twin-dosing AdBlue exhaust system helps the new car achieve 34.4mpg (28.64mpg US) with CO2 output from 216g/km.

European deliveries are expected early 2021 and the model will be offered in two formats, SQ5 TDI and SQ5 TDI Vorsprung, the latter featuring a comprehensive selection of extra features and driver aids.

Director of Audi UK, Andrew Doyle, said: “It’s the immediacy of the power delivery as much as the sheer force of the acceleration that makes such a lasting impression in the SQ5 TDI. Now that the formidable engine and independent electric compressor have been primed to perform even more readily and even more efficiently, and the successful SUV they power has been updated inside and out, the SQ5 TDI promises to be even more crushingly effective as a driver’s car and as an ownership proposition.”

— Paul Myles is a seasoned automotive journalist based in London. Follow him on Twitter @Paulmyles_