Five-Point Inspection: 2015 Audi A8 L TDI quattro Tiptronic

1. Fuel Economy

When it comes to efficient transportation, large luxury sedans are far from the best choice. They prioritize comfort and technology over miserly motoring. Still the A8 L TDI has a few tricks up its cufflink-bedecked sleeve.

This lengthy flagship four-door is propelled by a 3.0-liter diesel V6. The smooth-running compression-ignition engine provides tons of torque at very low speeds. It delivers a rather modest 240 hp but a crushing 428 lb-ft of twist at just 1,750 RPM. That’s scarcely past idle! Furthermore, this little oil-burner is shockingly refined, putting the notion that diesels are clattering, chugging, smoke-belching industrial goods to rest.

Despite putting out truck-rivaling torque this engine is also surprisingly efficient. Aided by an eight-speed automatic transmission the A8 L TDI stickers at 24 miles per gallon city, 36 highway and 28 MPG combined. Across the board that’s better than a V6-powered Honda Accord. During my testing I averaged nearly 30 MPG in real-world driving.