and too fast to fall under the GT class regulations, forcing the ACO to promote them as prototypes. In 2000, changes were made to the LMP regulations, as the ACO once again split the open-cockpit LMP class. The two new classes became known as "LMP900" and "LMP675", with the numbers denoting the minimum weight requirements (in kilograms) for each class. The LMP900s were to be more powerful and faster in top speed, but also heavier and more cumbersome. The LMP675s were to be smaller and more nimble, yet lack the top speed of the larger class. Both classes were intended to be able to compete for overall wins. Audi, Chrysler, Cadillac, and Panoz opted to use the LMP900 formula, while MG were the only major manufacturer to attempt the LMP675 class. The LMGTP class also continued, with Bentley being the only manufacturer to build a closed-cockpit prototype after the regulation changes in 2000. In 2017, in order to limit the costs, FIA introduced a new set of LMP2 regulations, which will be locked in through 2020, aiming for a significant power increase, to the range of 150 horsepower (which is expected to lead to a four-second decrease in lap time at Le Mans). Gibson Technology is the exclusive engine supplier for LMP2, producing a four-litre normally-aspirated V8. Technical regulations Biofuels, specifically petrol with 10% ethanol and biodiesel (BTL), are allowed in both LMP1 and LMP2 categories. LMP1 The fuel tank size and minimum weight for non-hybrid cars was subject to adjustment to reduce the difference in performance between hybrid and non-hybrid cars. There were no limits on the number of cylinders for any type of engine. Bodywork was required to cover all mechanical elements of the car, so that they couldn't be visible when the car is viewed directly from the front, side, or top. The LMP1 cars were generally the most powerful, with higher straight-line speeds. The LMP1 category was retired at the end of the 2020 season, replaced by a new top class of the endurance racing: Hypercar. LMP2 From 2017, in order to limit the costs, FIA introduced a new set of regulations, which will be locked in through 2025, aiming a significant power increase, to the range of 150 horsepower (which is expected to lead to a four-second decrease in lap time at Le Mans). Gibson Technology is the exclusive engine supplier, producing a 4.2-litre naturally-aspirated