When Audi’s R18 e-tron LMP1 racecar hits the Le Mans starting line next month, its TDI diesel engine won’t employ the help of an electrically driven turbocharger, as it had during early testing.
Although a clever idea, the electric turbo – which relies not on exhaust gases alone to spin the turbines, but could instead spin to full rpm by an electric motor – wasn’t performing as intended, according to Dr. Wolfgang Ullrich, Head of Audi Motorsport, and was scrapped.
Delightfully, Audi hasn’t given up on the technology. Instead of using it in a racecar, the German brand has instead opted to use it in the RS5 TDI concept you see above.
To create the RS5 TDI concept, Audi engineers ripped out the standard 4.2-liter V8 – shared with the R8 – and replaced it with a 3.0-liter turbocharged diesel V6 from the A7 TDI.
The addition of the electronically spooled turbos is nothing to spit at either. The engine – and driver – benefits from an additional 145 horsepower and 125 pound-feet of torque. While the standard clean diesel puts out a respectable 240 hp and 428 lb-ft, the RS5 TDI churns out 385 hp and 553 lb-ft.
Perhaps best of all, the extra torques come at an extremely low 1,250 rpm. This means that the RS5 TDI’s spine-contorting torque is available early and often, surely making it a literal scream.
Even though the tech isn’t right for Le Mans, I personally see it as ideal for road-going cars. Not only does the addition of the electric motor to the turbo aid in acceleration, it could be used to create electricity from the exhaust gas passing through the turbo on coast or deceleration. This before unutilized energy – albeit minimal – could be used to help run electronic accessories in the car. Or, perhaps better yet, for performance junkies, used to overboost the turbo on hard acceleration.
