In March 2017, Lotus announced the special edition ‘Sprint’ models of the Elise. For the Elise Sprint, Lotus used several weight-saving techniques to cut the car’s weight down to 798 kg (1,759 lb). To achieve the 40kg weight saving, some body parts are made in carbon, as well as the seats. The backlight glass is made of polycarbonate, and the lightweight battery is a Lithium-ion model. Wheels are the usual size, but forged instead of cast alloy. The Sprint can be had with either a 1.6-litre naturally aspirated engine, or a 1.8-litre supercharged engine, available for the Sprint 220 version. The former has a 0-60 mph (97 km/h) time of 5.9 seconds, while the Sprint 220 can accelerate from 0-60 mph (97 km/h) in 4.1 seconds. Dampers are uprated, as on the Elise Cup models.