By John Oreovicz

IMSA Wire Service

DAYTONA BEACH, Fla. – Making sense of the three classes of prototypes that compete in the IMSA WeatherTech SportsCar Championship can be a challenging proposition.

At first glance, cars built to Le Mans Prototype 2 (LMP2), Le Mans Prototype 3 (LMP3) and even the new Grand Touring Prototype (GTP) specifications look somewhat similar – especially when viewed on the high banks of Daytona International Speedway running 200 mph in the dead of night. But there are key factors that differentiate the cars from each class – visually, aurally, technologically and financially.

In simple terms, think of LMP3, LMP2 and GTP as the “Small, Medium and Large” of prototypes. Or “Fast, Faster and Fastest.”

Le Mans Prototype 3

LMP3 was created as a cost-effective entry to prototype racing that has proven valuable for young up-and-comers and less-experienced drivers. Cars are available from four approved constructors (Ligier, Duqueine, Adess and Ginetta) for a homologated price of approximately $250,000, all powered by an Oreca VK56 V-8 engine producing more than 450 horsepower. The LMP3 field expected at the Rolex 24 is almost evenly split between Ligier (5) and Duqueine (4) chassis.

To control costs, LMP3 cars incorporate a steel tubular roll cage into a composite chassis. They also utilize steel brake rotors as opposed to carbon. LMP3 cars measure 183 inches in length, 75 inches in width, with a minimum weight of 950 kilograms (2,090 pounds). LMP3 cars may also be identified by the orange coloring in designated places on the car, including the mirrors, rear-wing endplates, class plates and the lighted led position indicators.

Le Mans Prototype 2

LMP3 to LMP2 represents a shift to a higher level of race car technology. The LMP2 chassis is full composite; the 4.2-liter, 500-horsepower Gibson V-8 is purpose-built for endurance racing, featuring a flat-plane crankshaft that creates a screaming exhaust note. There are four approved constructors (Ligier, Multimatic, Dallara and ORECA), and the homologated price is $506,000. ORECA is the only LMP2 chassis on the Rolex 24 entry list, which has been the case over the past few seasons.

An LMP2 car is fractionally longer than an LMP3 and weighs the same. LMP2 cars may also be identified by blue coloring in designated places such as the mirrors, rear-wing endplates and class plates. Lighter, more powerful and with full carbon brakes, an LMP2 prototype laps a typical circuit about five seconds faster than an LMP3. These are fully professional race cars that require a professional level of engineering and maintenance.

Grand Touring Prototype

In 2023, the GTP class will feature cars built to LMDh technical regulations developed by IMSA and the Automobile Club de l’Ouest (ACO). GTP cars are identifiable by the black background on the class plate.

The LMDh formula mandates affiliation with an established automotive manufacturer that produces more than 2,500 vehicles annually for worldwide sale. Four such manufacturers have committed for the 2023 season (Acura, BMW, Cadillac and Porsche); Lamborghini has announced its intent to join the WeatherTech Championship GTP class in 2024.

Each manufacturer partners with one of the four approved LMDh "spine” constructors. The spine includes a full-composite central chassis, suspension, and braking system. BMW and Cadillac have linked with Dallara, Acura with ORECA, Porsche with Multimatic and Lamborghini with Ligier for their LMDh spine providers.

LMDh manufacturers contribute stylized bodywork with their own brand language to that LMDh spine base, and they also enjoy a great deal of freedom with regard to the powertrain. The rules allow any gasoline-powered, four-stroke internal combustion engine (ICE) with a 10,000-rpm limit, as long as it integrates to Bosch’s mandated Motor Generator Unit (MGU) – the hybrid technology unit built into the common seven-speed Xtrac gearbox used by every LMDh car as part of the common Energy Recovery System (ERS). Batteries and other common components for each car’s hybrid system come from WAE Technologies.

Not only does every GTP/LMDh competitor look different, they also sound different because the manufacturers made radically different choices in terms of their “traditional” engine. Acura developed a twin-turbo V-6; Porsche and BMW have opted for turbocharged V-8s, while Cadillac chose a 5.5-liter, naturally aspirated V-8.

While Cadillac, Acura, BMW and Porsche are fielding full-fledged, factory-supported programs in the 2023 WeatherTech Championship, Porsche also will sell its 963 Hybrid to qualified customer teams. The asking price is $2.9 million, which includes full factory engineering support. That figure alone should tell you that an LMDh prototype is a no-compromise, ultra-technology racing car.

GTP entries are relatively easy to spot on track because they are so much larger than the LMP2 and LMP3 runners. LMDh cars can measure up to nearly 201 inches in length and 79 inches in width. Although they weigh 1,030 kilograms (2,270 pounds), the additional power (643-697 horsepower made at the rear wheels, to be determined for each manufacturer via IMSA’s Balance of Performance process) and superior aerodynamics will make GTP cars much faster than the other classes of prototypes in terms of lap time.

How much faster? Because GTP/LMDh is totally new, we won’t really know until the WeatherTech Championship opens the 2023 season at Daytona International Speedway with the Roar Before the Rolex 24 from Jan. 20-22, followed Jan. 26-29 by the Rolex 24 At Daytona race week. No matter which class you focus on as IMSA kicks off an exciting new era, it’s guaranteed to be a can’t-miss event.