The Porsche 911 Carrera RSR 2.8 is a race car built by Porsche in 1973 for the historic Group 4 racing class. The 2.7 flat-six engine found in the street-legal Porsche 911 Carrera RS 2.7 was bored to 2.8 litres and received a higher compression ratio, resulting in a 101 bhp increase. Handling was improved by fitting wider rear tyres and wheel arches, as well as by using brake discs from the Porsche 917. The RSR 2.8 was replaced by the Porsche 911 Carrera RSR 3.0 in 1974.