Two-stroke engines used to be ubiquitous in dirt bike racing, thanks to their lightweight construction and horsepower. Packed in a dirt bike frame, they make a motorcycle playful in the corners and ...

Automobile engines have undergone tons of changes over the years, primarily to make them more efficient. For the most part though, engine changes result from a string of iterative improvements on ...

The basic difference between direct injection (DI) and the port-fuel injection (PFI) systems we've become familiar with since the mid-1980s is that PFI sprays fuel into the intake manifold (behind ...