"In the early 20th century, bigger engines existed, both in road cars and sports cars. Due to the absence of displacement limit regulations, manufacturers took increasing liberties with engine size. In order to achieve power over 100 horsepower (75 kW), most engine builders simply increased displacement, which could sometimes achieve over 10.0 L. One of the biggest straight-4s of its time was De Dietrich 17,000 cc motor. "