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Are you new to Sports Cars Racing? Curious about the differences between LM GTE & GT3? Curious about the difference between LM GTE? No worries, we’ve got you covered. Ahead of the resumption of motorsport worldwide, we’ve decided to produce articles introducing Sports Car Racing to our readers. Part is an in-depth introduction to the main Prototype classes used in Sports Car Racing today.

Unlike GT racers, Prototypes are purpose-built racing cars with enclosed wheels, and have either open or closed cockpits, with no production minimum required. Prototypes represent the pinnacle of sportscar racing and are just as quick and technologically advanced as their single seater counterparts.

Currently, there are 5 main classes of Sports Car Prototypes:
1. Le Mans Prototype 1 (LMP1-HY/LMP1)
2. Daytona Prototype International (DPi)
3. Le Mans Prototype 2 (LMP2)
4. Le Mans Prototype 3 (LMP3)
5. Group CN

Le Mans Prototype 1 (LMP1)

Toyota Gazoo Racing – Toyota TS050 Hybrid #7 – Image by Kevin Decherf on Flickr

LMP1 is currently the fastest prototype class in the world, with all cars being closed cockpit prototypes since 2014. It is a fully Professional class, with Bronze rated drivers being prohibited (unless a waiver is given, as was the case with Hendrik Hedman for the 2018/19 WEC Superseason). It is divided into 2 subclasses, LMP1 and LMP1-Hybrid. The Non-Hybrid LMP1 class is exclusively reserved for independent private teams.

Independent Private Teams are defined as follows in the regulations:” a team that does not benefit from any support from a manufacturer other than for the single supply of engines, services relating to these engines or commercial support. Any support from a manufacturer relating to the chassis or to chassis systems is prohibited. It is understood that traction control is considered as a chassis system.”

Equivalence of Technology, or EoT, is applied to allow for LMP1-NH cars to compete against LMP1-HY cars on “equal” footing. EoT controls the fuel flow and capacity each of each type of car (NA-Petro/Turbo-Petrol/Turbo Petrol-Hybrid). To keep the championship tight, and success handicap is applied in the class, with cars penalised by 0.008 seconds per kilometre, for each point by which they lead the last-placed entry in the LMP1 championship classification.

For LMP1-HY, the handicap criteria is the following: fuel flow rate, the petrol allowed per lap/stint, hybrid system deployment, and refuelling rate

For LMP1-NH, the criteria are the minimum weight, fuel flow, petrol per stint, and the refuelling rate. However, for LMP1-NH, the minimum weight of the cars will not be raised above 870kg

LMP1 class technical regulations list out the following key specifications:

  • Engine size is free for LMP1-Hybrid cars
  • Engine size is limited to 5.5L for LMP1-Non Hybrid cars
  • For both classes, cylinder count is free.
  • Only four-stroke Petrol and Diesel engines (HY only) are allowed
  • Car Dimensions:
    • Minimum Weight: 833kg (NH)/878kg (HY)
    • Maximum Width: 1900mm
    • Minimum Width: 1800mm
    • Maximum Wing Width:
    • Maximum Height: 1050mm
    • Maximum Length: (including rear wing)
    • Front Overhang: 1000mm
    • Rear Overhang: 750mm
    • Maximum Wheel F/R width: 13”
    • Wheel Diameter: 18”
    • Brakes: 15” Free Materials
    • Fuel capacity:         
      • Hybrid-Petrol: 62.3L
      • Petrol: 75L
      • Hybrid-Diesel 50.1L

Allowed driving aids:

  • Engine-based traction control
  • Power Steering. (Only for the sole purpose of reducing the effort required to steer)

All other driver aids, such as ABS and Power Braking, are prohibited, alongside Four-Wheel Steering.

Daytona Prototype International (DPi)

#55 Mazda RT24-P Mazda Team Joest Image by Osajus Photography on Flickr

Introduced in 2017, the Daytona Prototype International (DPi) class is the spiritual successor to the original Daytona Prototypes. DPis are standard ACO/FIA homologated 2017 LMP2 chassis fitted with IMSA-homologated, manufacturer-designed & branded, bodywork and engines

To compete in this class, prospective manufacturers must partner with one of the four approved constructors and commit to a bodywork and engine package. Specific areas of the bodywork regulations allow manufacturers to have design and stylistic freedom to create recognition for their specific brands. These areas include the nose and sidepod areas, rear-wheel arch and rear valance. Wing Profiles are prohibited in such zones

A wide variety of production-based engines may be utilised, including V10 and V8 engines. Besides production-based engines, GT3 engines can also be used. However, turbocharging is only allowed on four- and six-cylinder engines.

Balance of Performance is applied in the class, to discourage excessive development. It is applied through the following: Aerodynamic adjustments, fuel capacity adjustments, weight changes, turbocharger boost and air restrictor size changes. Wind tunnel and dynamometer testing is also performed on cars to establish a baseline specification for all new cars.

Initially, the class was planned to race in Le Mans, in the LMP2 class, before numerous disagreements occurred between the ACO and IMSA.

LMDh will replace DPi for the 2022 racing season. Prior to the 2020 24 Hours of Daytona, LMDh was known as DPi 2.0.

Le Mans Prototype 2 (LMP2)

 Panis Barthez Competition – Ligier JSP217 – Gibson #23 – Image by Kevin Decherf on Flickr

The second tier Prototype class in the FIA World Endurance Championship and the IMSA WeatherTech Sports Car Championship, used as the Top Class in the Asian Le Mans Series, and the European Le Mans Series. In all championships, LMP2 is a Pro-Am class. All teams must have one Amateur driver, with either a Bronze or Silver-rated driver in each car.

Since 2017, all LMP2 cars have been closed cockpit.

Costs are tightly controlled, with the regulations stating the following:

“The selling price of the complete new car without the single engine neither the homologated electronic equipment must not exceed 483 000€.”
” The Chassis Constructor must provide the FIA the price list of spare parts. The total of this price list must not be more than 140% of the selling price of the complete new car.”

However, there is a caveat to this, the technical regulations state:

  • ”A 20% increase of the spare parts price is allowed if a Chassis Constructor is providing a sale services of these parts on the race meetings.”

    However, this price does not include extra options, which include:
  • The air conditioning system (mandatory and homologated), 7000€ max
  • The Optional rear view camera system (homologated)
  • The Optional telemetry system;
  • The Optional Tyre Pressure Monitoring System.

Unlike LMP1, where teams can design and build their own chassis, LMP2 teams may not do so. LMP2 is a tightly controlled formula, with only 4 chassis manufacturers (Ligier, Oreca, Dallara, Riley-Multimatic). These manufacturers were required to bid for a license in 2015. The powertrain consists of the following: A spec engine, the Gibson GK428 producing 600 horsepower, paired to a 6-speed gearbox, and a Cosworth Electronics package.

Bodywork in the class is homologated, and can only be altered once. This alteration is considered as a “Joker” upgrade, and can only be done once. 3 Of the 4 cars, the Ligier, Dallara and Riley, received upgrades in 2017. 2 aerodynamic configurations are used: A high-downforce kit for use on all tracks, and a low drag kit for Le Mans

  • Car Dimensions:
    • Minimum Weight: 930kg
    • Maximum Width: 1900mm
    • Minimum Width: 1800mm except for the most forward 50mm of the car
    • Maximum Wing Width: 1800mm
    • Maximum Height: 1050mm
    • Maximum Length: 4750mm (including rear wing)
    • Front Overhang: 1000mm
    • Rear Overhang: 750mm (including rear wing)
    • Maximum Wheel F/R width: 12.5” & 13”
    • Wheel Diameter: 18”
    • Brakes: 15” Free Materials
    • Maximum Fuel capacity: 75 Litres

The following driver aids are allowed:

  • Engine-based traction control
  • Power Steering. (allowed for the sole purpose of reducing effort required to steer)

Other driver aids, such as ABS and Power Braking, are prohibited, alongside Four-Wheel Steering.

Le Mans Prototype (LMP3)

#85 DC Racing – Ligier JS P3 – Nissan – Image by
Kevin Decherf
on Flickr

Introduced in 2015, it is the third tier Prototype class in ACO & IMSA competition. It is one of the most widely raced prototype classes globally. The class replaced Formula Le Mans, also known as the Le Mans Prototype Challenge (LMPC). 2020 marks the beginning of the 2nd generation rules cycle for the category

LMP3 is meant for young drivers and teams, new to endurance racing. The class serves as a stepping stone before advancing to the higher prototype classes. Hence, it is mainly an amateur class, with the majority of the championships requiring line-ups to include one bronze driver, while the remaining drivers in the line-up may be Silver or Gold. However, the driver lineup rules vary from series to series.

Costs are tightly controlled, with the regulations stating the following:

“The selling price of the complete new car, complete with the engine described and elected by the ACO must not exceed 239000€ (including the electronic passport).”  

– “The selling price of the conversion kit for the 2020 regulations must not exceed 50000€ (including the electronic passport)”

– ” The Manufacturer must provide the ACO the price list of spare parts. The total of this price list must not be more than 150% of the selling price of the complete new car.”

Like LMP2, LMP3 is a tightly controlled formula, and teams may not build their own chassis. There are only 4 chassis manufacturers (Ligier, Ginetta, Duqueine and ADESS). These manufacturers received a new license for the 2020 regulations. The Ave-Riley partnership did not have it’s license renewed for the 2020 regulations. LMP3 uses a spec powertrain, consisting of a Nissan VK56 engine producing 455 horsepower, paired to a 6-speed gearbox

  • Car Dimensions:
    • Minimum Weight: 950kg
    • Maximum Width: 1900mm
    • Minimum Width: 1800mm
    • Maximum Height: 1050mm
    • Maximum Length: 4650mm (including rear wing)
    • Front Overhang: 1000mm
    • Rear Overhang: 750mm (Rear wing included)
    • Maximum F/R width: 12.5” & 13”
    • Maximum Wheel Diameter: 18”
    • Max Fuel capacity: 100 Litres
    • Brakes: 14” Steel
  • From 2020, LMP3 cars will have traction control

Group CN

Norma M20 – Image by AlessioMoscetti on Flickr

Group CN is the lowest prototype class. CN is used in both Sports Car, and Hill Climb Racing. CN is used only in National championships, and has a mix of open and closed cars.

All cars utilise 6 speed gearboxes, with a maximum of 6 cylinders for engines, with an engine size limit of 3.0L for Naturally Aspirated Group N engines and 1.62L Supercharged Group N engines

  • Car Dimensions:
    • Minimum Weight: Engine Size Dependent
    • Maximum Width: 2000mm
    • Maximum Width (F/R Wing): 1300mm/1800mm
    • Maximum number of wing elements: 2
    • Maximum Height: 1030mm
    • Maximum Length: 4800mm Overall
    • F/R Overhang: No more than 80% of Wheelbase, the difference between F/R Overhang is not to exceed 15%
  • Four-wheel drive and four-wheel steering is prohibited

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