1. smart fortwo: 1.0L (999 cc)
Finally, the smallest engine on our list belongs to the 1.0-Liter, three-cylinder engine that’s inside the smart fortwo. Here it makes a sweet 70hp, which is good for an EPA rated 34/38 mpg. The engine requires premium fuel, like a few other vehicles on this list, but its also worth mentioning that this is the only car on the list that is rear-engine and rear wheel drive. The smart fortwo isn’t as cheap as the Chevy Spark, and costs $12,490 for the extra fuel efficiency over the American micro-subcompact.