Porsche Of The Day: 1973 Porsche 911 Carrera RSR 2.8
1973 Porsche 911 Carrera RSR 2.8 | Image Courtesy of FavCars
Most Porsche fans know little about this epic wide-bodied 911 based race car. While the iconic 2.7 RS is every fan boys dream car, the RSR is the whole reason for the RS’s existence in the ﬁrst place so we are dedicating some space here to tell you all about it. Introduced in 1973, the RSR was a factory-built racing car based on the 911 chassis.
The 2.8 RSR looks different from a standard 2.7 RS because of its massive fender flares, central oil-cooler air intake, and ultra-wide Fuchs wheels. While the wider wheels and arches combined with the low air dam to give the RSR a much more aggressive look, the conversion process was much more than just a bunch of tweaks, it was a serious engineering exercise.
At the heart of the RSR of course was an enlarged race engine. Porsche’s goal was to get as close as they could to the 3 liter class limit engine size. The cylinder bores were enlarged to 92 mm, giving a total volume of 2806 cc, and the compression was raised to 10.3:1. The cylinder heads were modiﬁed for larger valves and valve timing was that of the 906 sports racer. Bigger valves, twin-plug ignition, high throttle butterﬂies and extensive lightening of internal components contributed to an increase from the 210 bhp of the RS to over 300 bhp. That the RSR’s type 911/52 engine was able to produce a reliable 300 hp at 8,000 rpm was a huge accomplishment for Porsche engineers.