The compression ratio of the 2019 Porsche 911 GT3’s 4.0L flat-six is 13.3:1.
This engine belongs to the facelifted 991.2-generation GT3, sold from 2017 through 2019. Porsche enlarged the naturally aspirated flat-six to 3,996 cc and gave it a high compression ratio to improve thermal efficiency and power without turbochargers.
The result was 500 hp at 8,250 rpm and 460 Nm of torque at 6,000 rpm, with a 9,000-rpm engine limit. The design used direct fuel injection, four valves per cylinder, dry-sump lubrication and VarioCam timing control for both intake and exhaust camshafts.
The figure is sometimes confused with specifications for other 911 variants or the GT3 RS. Those models share much of the 4.0-litre high-revving architecture, but power, torque and calibration can differ. Compression ratio also should not be confused with the engine’s redline: 13.3:1 describes the cylinder-volume relationship, while 9,000 rpm describes rotational speed.