You probably wouldn’t expect a car that bears the declaration, “the cleanest diesel in the world,” to be much fun to drive. But the A5 3.0 TDI — one of two such examples we drove recently — is remarkably responsive. The car that stands up to this claim — the very same one that ran recently in the Challenge Bibendum in Shanghai — is equipped with a six-speed automatic transmission plus, to make it better than 50-state legal, a urea-injection system that sprays a solution called AdBlue into hot exhaust gases to reduce NOx emissions.
The AdBlue solution is stored in a 6.2-gallon tank and lasts at least 10,000 miles, such that you’ll never have to worry about it between oil changes. And if the driver ignores all of the warnings to refill the reservoir, the engine computer will very gradually and safely limit the engine’s power, according to Günther Schiele, head of TDI engine development for the automaker.
The U.S. A5’s top engine, the 265-hp, 3.2-liter V-6, brings the coupe to 60 mph in 6.1 seconds. But in Europe the same clean-diesel A5 3.0 TDI (minus the urea system) makes for a faster version that slots between the gasoline 3.2 and the V-8-powered S5.
In the A5 it knocks two tenths off that dash to sixty, allows it to hit a 155-mph top speed, and feels considerably more powerful in real-world driving, compared to the V-6.
I recently drove the A5 3.0 TDI and an S5 within a few days of each other, and the comparisons were intriguing at the least — especially when the TDI was equipped with its standard six-speed manual.
Source: The Car Connection