Toyota's TS050 is the favorite to win the Prototype 1 category at this year's Le Mans 24-hour endurance race - but it won't be from lack of trying from privateer race teams newly permitted to use non-hybrid drivetrains in the LMP1 class. (Toyota)

Le Mans 2018: can anyone beat Toyota’s hybrids?

Arguably the pinnacle of auto racing technology, the World Endurance Championship’s 24 Hours of Le Mans is in a period of transition for 2018-19. The FIA sanctioning body has dubbed this period a “super season” for the WEC, during which rules for the 2020 race are being formulated. The goal: attract factory teams back to the world’s premier endurance event, the 86th running of which is set for June 16-17, 2018.

Last year, Porsche and Toyota were the sole factory contenders in the excruciatingly expensive Le Mans Prototype 1 (LMP1) category. After notching its 19th win in the endurance classic, Porsche quit the WEC, citing plans to instead focus on the vastly cheaper battery-electric Formula E series.

“This realignment of motorsport activities for Porsche stems from the direction set out for the company in Porsche Strategy 2025, which will see Porsche develop a combination of pure GT vehicles and fully electric sports cars,” the automaker explained in a statement regarding its decision to make last year its last in WEC racing.

Porsche’s departure left Toyota with no factory-backed rival for this year’s race. In response, the FIA scrambled to formulate less costly (read: not requiring hybrid technology) LMP1 rules that would let private teams challenge Toyota for the win in this prestigious class. The strategy generated a field of eight cars—fielded by five teams—to take on the engineering might of Toyota using chassis and engines available from traditional racing suppliers.

Fuel energy and consumption rules

The interim regulations for 2018/19 give private non-hybrid LMP1 teams 210.9 megajoules (58.6 kW·h) of fuel energy per lap of the 13.62 km (8.47 mi) circuit, compared to the 124.9 MJ (34.7 kW·h) available to the Toyota TS050 Hybrid LMP1-H. Its hybrid-electric drive will add another 8 MJ (2.2 KW·h) per lap.

In addition to limits for total fuel consumption, the FIA also restricts instantaneous fuel flow, limiting the factory hybrid cars to an 80 kg/h rate, compared to 110 kg/h for the non-hybrid privateers. Combustion-engine displacement is unlimited for LMP1, while LMP1-H cars are limited to a maximum displacement of 5.5 L. Finally, the non-hybrid cars are allowed to run 45 kg (99 lb) lighter, with a minimum mass of 833 kg (1836 lb), versus an 878 kg (1936 lb) minimum for Toyota’s hybrids.

Engines are limited to a maximum of four conventional poppet valves and electromagnetic, hydraulic and pneumatic valve-actuation systems are forbidden. Further, variable valve timing and variable valve lift systems are not allowed, but teams are free to employ high-tech plasma, laser and other high-frequency ignition systems.

LMP1 fuel tanks are limited to 75-L (19.8-gal) capacity, which corresponds to the FIA’s 52.9 kg (116.6 lb) fuel limit, while LMP1-H’s fuel capacity is set at 35.2 kg (77.6 lb), corresponding to a 50-L (13.2-gal) fuel tank.
Engine ancillary systems can be driven mechanically from the engine or electrically by dedicated electric motors, but if they are electric, the drive cannot also be connected to the engine mechanically. Power brakes are prohibited and calipers must be of aluminum and contain a maximum of six pistons. Brake rotor material is unrestricted, but diameter is limited to 15 in (37.5 cm).

The overall intent is to give lower-budget privateer LMP1 teams a glimpse of opportunity to unseat the Toyota “works” juggernaut. And over the course of 24 hours, it is entirely possible that could happen, as Toyota saw in 2016 when, while leading on the last lap, a breakdown handed victory to Porsche.

"Our obvious target is delivering a significant step-up compared to the past, but honestly, we are raising our game,” said ByKolles team principal Manfredi Ravetto. “We are proud of being manufacturers in LMP1, which is the ideal stage for our constantly-growing structure and we are grateful to ACO and FIA for organizing and promoting such a championship, nowadays second to none in the world.”

But in pre-season testing—and in the 2018 season-opening race at the 6 Hours of Spa-Francorchamps—the Toyota TS050 Hybrids enjoyed a decisive advantage over the non-hybrid privateers, even while they probably were sandbagging to avoid any further handicapping for the Le Mans race. The Toyota TS050s finished first and second at Spa, with a race pace of 1:57.805, which was 1.2 seconds faster per lap than the third-place Rebellion R13 non-hybrid. In qualifying, the gap between the Toyota’s and the rest of the field was 2 seconds, before the pole-winning TS050 had its time disallowed for an administrative mistake regarding replacement of a fuel-flow limiter.

Inside Toyota’s TS050

Toyota is aiming to make Le Mans history in 2018, with a goal of running a record distance to demonstrate the TS050’s speed. Indeed, in 2017 the car already set a record lap time, while using 35% less fuel compared to the team's 2012 car.
Team engineers note that they have made “small but productive” upgrades to the TS050’s aerodynamics compared to last year and have added a Gentex-supplied rear-view camera to help spot overtaking cars. Rear-view cameras are a new requirement for 2018, but probably not be terribly important for the Toyotas unless they break down. The team says it also has modified the car’s 1,000-hp (746-kW) hybrid-electric powertrain for improved reliability.

"Unlike previous years, the upgrades on our 2018 car are limited,” stated Pascal Vasselon, Toyota Gazoo Racing technical director. “In addition to reliability improvements on the powertrain, we updated the cooling system and developed the bodywork within our 2017 homologation.”

In terms of outright performance, Toyota has since 2014 had “a car fast enough to win Le Mans on three occasions, with no fundamental reliability issues,” Vasselon asserted. “Nevertheless, we failed every time to win so we had to do something about it.”

The TS050 carries over its twin-turbocharged, direct-injected 2.4-L gasoline V6 producing an announced 500 hp (373 kW) and supplemented by an Aisin AW-supplied traction motor driving the car’s front wheels and a Denso e-motor on the rear axle. They combine for an additional 500 official horsepower, with power routed from the lithium-ion battery pack through a Denso inverter.

Race teams habitually underrate their car’s performance to avoid tipping their hands to competitors or regulators—the conveniently round numbers Toyota claims seem a sure sign of that conservative approach, so the TS050’s true power output surely is higher.

Chinese and Russian privateers

For the privateers, the challenge is to identify the most competitive possibilities from the available chassis and engines to produce cars that will beat their fellow privateers, while keeping close enough to Toyota to be able to capitalize on any problems they might encounter during the long 24-hour race.

For chassis, Switzerland’s Rebellion Racing commissioned LMP2 constructor and longtime Le Mans stalwart Oreca to create its R13 racecar. Austria’s ByKolles Racing runs a Lotus Racing-designed chassis that the team calls the ENSO CLM P1/01.

The Chinese CEFC TRSM Racing team fields a Ginetta G60-LT-P1 chassis, while both America’s Dragonspeed and Russia’s SMP Racing employ the BR Engineering BR1, a car designed by Russia’s BR Engineering and constructed by Italy’s Dallara.

If these various chassis don’t provide enough variety of potential, consider the engines the teams are using. Rebellion and Dragonspeed both chose Gibson Technology’s GL458 4.5-L V8. ByKolles is attempting to salvage some glory for the Nissan Nismo VRX 30A, a twin-turbo, direct-injected gasoline 3.0-L, 60-degree V6 that originated in Nissan’s 2015 front-drive GT-R LM Nismo car.

SMP Racing’s entry is fitted with an AER-supplied twin-turbo V8 producing more than 800 hp (596 kW) and 590 lb·ft (800 N·m). By comparison, the CEFC TRSM team uses a Mecachome V364 3.4-L reverse-flow, single-turbo V6. It’s a development of the company’s LMP2 engine, updated with direct injection and a modified turbocharger, combustion chamber, pistons and valves. Though Mecachrome produces most of the engine components at its factory in France, the valves are sourced from Zanzi, valve springs from NHK and Pankl provides the pistons and connecting rods.

“The project for this new V6 engine started about two and a half years ago,” noted Bruno Engelric, Mecachrome’s Motorsport Director. “We agreed to build new engines for the GP3 Series and FIA Formula 2 Championship, so when the LMP1 program was launched, it was obvious that this engine would be the perfect basis.”

Gibson Technology’s rival GL458 4.5-L V8 LMP1 engine for Rebellion is based on the company’s 600-hp (447-kW), 410-lb·ft (556 N·m) GK428 LMP2 power unit. Gibson won’t specify the GL458’s output, but John Manchester, Gibson Technology’s Operations Director, said it’s a “significant” increase over the GK428’s rating. The LMP1 engine (based on the LMP2) employs about 30% different parts, including the crankshaft, rods and pistons. “We put in a lot of work on weight reduction, including some significant materials changes,” he said.

“The timeframes required meant that a ‘ground up’ design could not have been achieved in under six months,” Manchester explained, while meeting cost targets.
Among the privateers, cost-effectiveness is all important. And it is significant to manufacturers as well. Expect to see limits on costly technologies when the FIA issues rules for the 2020 WEC season. Continue reading »