Porsche 919 Hybrid
Porsche revealed an evolution of the 919 Hybrid on 11 April 2018, as it broke the lap record in Circuit de Spa-Francorchamps with a lap time of 1:41.77, with Neel Jani behind the wheel. The lap time was 0.783 seconds faster than Lewis Hamilton's flying qualification lap in 2017, previously posting a 1:42.553 in his Mercedes AMG F1 W08, a Formula One car. Jani was also over 12 seconds faster than the standard 919 Hybrid's 2017 pole position lap time of 1:54.097. During the lap, Jani's speed trap was at the Kemmel Straight, with an average speed of .
Porsche 935
Under Group 5 rules, also known as "silhouette rules", several significant modifications were allowed (including bodywork modifications, larger wings, wider axles and water cooling), provided that the basic silhouette of the car remain unchanged when viewed from the front. The 935's engine was a (at 7,900 rpm) version of the regular 3.0 L flat-six, with 60 mkp (438lb-ft, 588Nm) torque at 5,400 rpm. Boost was between 1.35 and 1.55 and fuel consumption was 52 litre per 100 km. Capacity was reduced to 2.85 L, and with the turbo charging penalty factor of 1.4, it fit into the 4.0 L class which had a prescribed minimum weight of only . Porsche, having a lot of experience with lightweight cars, had managed to get the Carrera RSR prototype to under 800 kg. The empty 935 tipped the scales at 900 kg, and weight distribution could be balanced with an additional 70 kg. Preseason testing at the fast Paul Ricard circuit showed a top speed of .