Le Mans Ultimate Virtual Energy Tank System: NRG guide

Featured image: Toyota GR010 HYBRID

Le Mans Ultimate is a proper simulation of the FIA World Endurance Championship, and since it left early access with its 1.0 release in 2025 it models the full modern grid – the Hypercars, and the LMGT3 cars that replaced the old LMGTE Am class.

That includes the championship’s hybrid ruleset, where cars in the top-level Hypercar class have to manage a ‘virtual energy tank’ to reach the end of a stint. It catches a lot of people out. Below we’ll work through how the virtual energy system works, where it comes from in the real WEC regulations, and how to get the most out of regenerative braking and hybrid deployment on track.

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WEC Hypercar rules | Virtual Energy Tank | Regenerating energy | Managing NRG | Hybrid driving guide

What are WEC’s Hypercar rules?

WEC’s Hypercar class is divided into LMDh and LMH cars. LMH (Le Mans Hypercar) cars are designed from the ground up by manufacturers and don’t require hybridisation.

Toyota, Ferrari, Peugeot and Aston Martin all run LMH cars, with the hybrid driving the front axle for a form of four-wheel drive. That sounds like a huge advantage, but the front motor can only deploy above roughly 190 km/h (around 118 mph), and the exact figure is set by Balance of Performance. It’s the same in the dry and the wet now – the old wet-weather variation was dropped to pull the LMH cars back towards their rear-drive rivals. The one exception is the pitlane.

The grid has come a long way from the days when Toyota, Ferrari and Peugeot were the whole story. A wave of LMDh cars – Cadillac, BMW, Alpine, Porsche and Lamborghini among them – has joined, and the Hypercar field is now one of the deepest in modern endurance racing. Every current Hypercar runs hybrid assistance, which is why virtual energy applies right across the top class.

LMDh manufacturers, on the other hand, have to use a certain number of common components to help keep costs down; including the motor generator unit (MGU), battery and gearbox.

Chassis’ can be purchased from either Dallara, Multimatic, Ligier or Oreca, but the manufacturer is allowed free-reign over its aerodynamic package and electronics. It must also supply its own internal combustion engine (ICE).

Although LMDh cars have hybrid systems, they are located on the rear axle only, so are strictly rear-wheel-drive.

Both types of Hypercars have their performance monitored and adjusted by the FIA and ACO, but are mandated to produce a combined total of 500kW / 671 bhp from their hybrid unit and ICE (most manufacturers’ ICEs are capable of 600 bhp alone, with hybrid units achieving  250 bhp+, but the actual split in power is down to team preference as long as it does not exceed 671 bhp in total). All cars also have to achieve a minimum weight of 1030 kg.

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The FIA and ACO dictate a Balance of Performance (BoP) calculation to the manufacturers to help ensure parity between all forms of Hypercar, adjusting power, weight and aerodynamic figures based on the relative performances of each car and detailed studies conducted by the governing bodies.

The BoP calculation is a secretive process and all WEC teams and drivers are forbidden from discussing it publicly for fear of bringing the championship into disrepute (teams love to complain about how unfair their BoP calculation is!).

What is the Virtual Energy Tank?

In simple terms, the Virtual Energy Tank (NRG) in LMU and the WEC is the amount of energy your car is mandated to use during a stint, based on a combination of fuel and electrical hybrid power (measured by a torque sensor attached to the MGU). LMU’s NRG bar is drained by deploying your car’s MGU battery and ICE under acceleration.

If your NRG hits 0% during a stint you pick up an instant stop-and-go penalty, so the whole game is using the battery efficiently and never letting the bar run dry. The NRG figure comes from a real-world BoP calculation set by the FIA and ACO, so you can’t adjust it in-game. Each car’s NRG level can be different, and it can change from track to track.

NRG only applies to the hybrid Hypercars, and it’s mostly there to cut fuel use over a stint. Running less fuel is kinder to your tyres and quicker over a lap, so getting the energy balance right matters more than it first looks.

How do Hypercars regenerate energy?

Hypercars store regenerated energy in their batteries. Regeneration occurs under braking, where the MGU acts as a generator on the drivetrain, converting the car’s kinetic energy into electrical energy, which is then stored by the battery.

You can adjust the regen level in LMU: the higher it is, the more braking power the MGU adds and the more electrical energy you capture. That shortens your braking distances, and it’s a big part of setting a quick lap in both the WEC and LMU.

How to manage NRG in Le Mans Ultimate

Accelerating with hybrid assistance drains the battery; braking puts some of that energy back. But with a full battery there’s nowhere for the energy to go, so regen stops and your braking drops off – which can pitch you into a spin. That’s why you want to keep deploying the battery rather than hoarding it.

Conversely, not having any battery to deploy under acceleration means you will burn more ICE fuel, negatively affecting your overall NRG allowance. Balancing fuel usage and hybrid deployment during a race stint is key.

To maintain your battery’s charge you can adjust two settings in-car. The first is ‘motor map’ and the other is ‘regen level’. Increasing the motor map uses more battery under acceleration, while higher regen levels allow more battery regeneration under braking. This also enhances your car’s braking power, providing a form of ‘engine braking’ from the MGU.

Using more of the battery on acceleration reduces the need to use fuel from the ICE, which is why teams won’t brim their fuel tanks during pitstops. More fuel equals more weight and less pace.

As the NRG level is a combination of both fuel and electrical energy, adding lots of fuel is pointless, as rules dictate you can only use a certain amount of energy.

You can assign motor map and regen level to wheel buttons or change them manually through the in-game MFD, but you’ll be reaching for them constantly, so map them to your wheel or a button box (our sim racing button boxes guide runs through the options).

Managing NRG is complicated, but the key takeaway for beginners is to pit before your virtual energy level drops to 0%. The first time this happens you will incur a 100s stop-and-go penalty, with each further violation resulting in further 100s penalties (just like in WEC). The NRG level resets to 100% during a pitstop, however.

Le Mans Ultimate: hybrid driving guide

Below, we’ll run through a few driving tips to help you get the best out of LMU’s virtual energy tank.

As above, run a high regen level to shorten your braking distances. That keeps your braking consistent across a stint. It also recharges the battery at the quickest rate, so counteract it with a high motor map value – but not so high that the battery empties too soon.

If your battery hits 100% charge you lose the braking help from regeneration, which wrecks your brake balance and can put you in the wall, so emptying the battery under acceleration matters just as much as filling it. The trick is balancing regen level against motor map, leaning on lift-and-coast and short-shifting to save a bit of fuel while you’re at it. It takes a few stints before it clicks.

One final tip is to ensure you don’t pit with a flat battery. Some Hypercars exclusively use MGU power exiting their pit box, so having zero battery means you can’t pull away from your box. Which would be quite embarrassing during a race…

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Topic: Le Mans Ultimate