Underlining the point is that the racecar uses a finely tuned version of the technology in Audi´s production cars: common-rail fuel injection. The system employs piezo-crystal injectors that open and close faster to more precisely control fuel flow and generate a more thorough burn. This helps fuel-efficiency and engine power while reducing emissions. It also allows the racecar to reach a staggering 650 horsepower at only 5,000 rpm, while its competitors must hit an ear-splitting 12,000 rpm to achieve that power. In production cars, the key bonus is mileage-Audi´s diesel Q7 SUV will get 23 miles per gallon. â€Common-rail injectors have taken away a lot of the attributes that plagued early diesels, like slow starts, lack of power and pollution,â€ says automotive technology consultant Mike Jackson.