F1 Glossary · cars
MGU-H
The MGU-H is a component that converts heat from exhaust gases into electricity to power the car and eliminate turbo lag.
What is the MGU-H?
The Motor Generator Unit - Heat (MGU-H) is one of the most sophisticated elements of the modern Formula 1 Power Unit. It is an electrical machine mechanically linked to the turbocharger’s shaft, positioned between the turbine and the compressor. Its primary role is to convert the rotational energy of the turbo—driven by hot exhaust gases—into electrical energy.
Unlike other recovery systems, the MGU-H is versatile. It acts as a generator by capturing energy from the exhaust that would otherwise be wasted, and it acts as a motor by using stored electricity to spin the turbocharger. This dual functionality allows the engine to maintain high boost levels even when the driver is not pressing the accelerator.
Performance and Efficiency
In a race scenario, the MGU-H is the key to "anti-lag." In traditional turbocharged engines, there is a delay between the driver hitting the throttle and the turbo providing power. In F1, the MGU-H uses electricity to instantly spin the compressor, providing immediate power.
Furthermore, the MGU-H is unique because, unlike the MGU-K (which recovers energy from braking), the MGU-H has no regulatory limit on how much energy it can harvest or deploy per lap. This makes it the "brain" of energy management, often funnelling electricity directly to the MGU-K to provide a continuous power boost down long straights without draining the battery.
Reliability and Recent Examples
Because the MGU-H operates at speeds exceeding 100,000 RPM in extreme heat, it is a frequent point of mechanical failure. During the 2022 and 2023 seasons, several teams faced retirements due to MGU-H seizures. When this component fails, the turbocharger typically cannot provide boost, resulting in a massive loss of horsepower and usually forcing the car to retire immediately.
Common Viewer Confusion
Fans often confuse the MGU-H with the MGU-K. The simplest way to distinguish them is their source: the MGU-K (Kinetic) deals with movement and braking, while the MGU-H (Heat) deals with exhaust gases and the turbocharger. While the MGU-K is limited to recovering 2MJ of energy per lap, the MGU-H can harvest unlimited energy, making it the primary driver of the car's hybrid efficiency.
Common questions
- Does the MGU-H have a deployment limit?
- No. Unlike the MGU-K, which is strictly limited by the FIA in how much energy it can harvest and deploy per lap, the MGU-H can harvest and transfer an unlimited amount of energy directly to the MGU-K or the battery.
- Why is the MGU-H being removed in 2026?
- The FIA and teams agreed to remove the MGU-H for the 2026 engine regulations to reduce manufacturing costs and technical complexity, making it easier for new engine manufacturers to enter the sport.
- What happens if the MGU-H stops working?
- If the MGU-H fails, the car suffers from significant turbo lag and a major loss of electrical deployment. Because it is so integrated with the turbocharger, an MGU-H failure often leads to a total loss of power and a DNF.