Specific output is a measure of engine performance. It describes the efficiency of an engine in terms of the brake horsepower it outputs relative to its displacement. The measure enables the comparison of differently sized engines and is usually expressed as kilowatts or horsepower per litre or per cubic inch. Generally, forced induction engines out-perform naturally aspirated engines of the same size by this measure.
- "2012 10Best: Highest-Specific-Output Engines". 6 December 2011. Retrieved 10 February 2016.
- Mark Stevenson (28 July 2015). "Average Gas Engine Specific Output Isn't Quite 100 HP/L, Yet". The Truth About Cars. Retrieved 10 February 2016.