One of Formula 1’s greatest innovations whilst overly expensive, the MGU-H is set to be discontinued from 2026’s power units.
The MGU-H, or Motor Generator Unit- Heat, is the GENIUS device that made Formula 1 engines one of the most responsive and efficient engines ever. FIA (or the Fédération Internationale de l’Automobile) ended up killing its prodigal son last week in lieu of cost cap restrictions, as voices grew over years on how expensive and unreliable these components are. After careful deliberations over recent months, FIA approved the removal of these little buggers from the 2026 engines.
But I, for one, cannot fathom the painful loss of such an engineering marvel, considering my affinity to the sport’s technical side.
So as an obituary, let’s take a step-by-step look into what even is the MGU-H and how it works, in as simple words as possible.
How does the MGU-H work? A skimmed rundown:
The MGU-H is an engine component primarily aimed at making the Formula 1 turbocharged 1.6L V6 engines as efficient as possible, while reducing the ever-annoying turbo lag. As the name suggests, the device is a “motor” as well as a “generator”. Let’s break it down.
The “generator” part first. As you might know, a turbocharger’s purpose is to build up high pressure air for an engine’s intake to improve power. To the uninitiated, turbos make use of exhaust gases to rotate a turbine which in turn pulls in more air into the engine. More air = better combustion = more power. Simple thermodynamics. Google “turbochargers” if you’re still in the blue.
Now, a turbocharger has the tendency to provide extra or unnecessary boost at certain times when its engine doesn’t need it. For any average road car, that boost just goes wasted as exhaust heat. But here’s where the MGU-H comes in a Formula 1 engine. It basically acts as a turbo waste-gate, harvesting energy from that otherwise wasted boost and exhaust gases.
The device is connected to the turbocharger (in varying configurations) with a shaft. Set to a max rpm of 125,000, the MGU-H scrapes its energy from that turbo shaft like a generator when the latter is over-delivering boost (e.g., on straights). Imagine a trough to collect overflowing water.
In a similar fashion, MGU-H harvests the extra torque when the ICE (internal combustion engine) is in its lower rpm ranges. The MGU-H sends this regenerated energy to the battery store or the big ol’ hybrid motor, in addition to the 160hp from MGU-K (Motor Generator Unit- Kinetic).
All of these harvest shenanigans have an implication worth worlds: engine efficiency. An average road-going internal combustion engine has an efficiency of about 20%, yes?
The 2017 Mercedes AMG W08 Formula 1 car’s power unit has an efficiency of over 50%! Yes, Fifty percent.
This made it one of the most efficient internal combustion engines in HISTORY. That was in 2017; one can only imagine what the figures are in 2022 (the numbers are not public for competitive reasons, of course).
Regeneration aside, the MGU-H has another job: to act as a motor. That’s where the “motor” part of its name comes in. Engine response is key in F1: whoever puts the power down quicker, goes faster. The MGU-H would keep the turbocharger spinning even when the throttle pedal is not pressed, so that as the driver slams his foot down exiting a corner, there is basically ZERO turbo lag. This is revolutionary, for the wheels now have instant torque in less than a blink, where any other engine would have to wait till the exhaust gases built the turbo’s boost.
This little gadget is in fact a lot, like *actually* a lot more complicated than the explanation here.
If not apparent already, the MGU-H is a well-deserved contender for “one of Formula 1’s greatest inventions” moniker. Recovering wasted energy, increasing engine efficiency by almost defying physics, and eliminating turbo lag in its entirety: the MGU-H was every team’s prized possession.
But then why is the MGU-H getting banned?
Why would anyone want to ban something this novel that also increases engine performance? The answer essentially lies in the direction Formula 1 is focusing for 2026. FIA wants to make the playing field level between all the teams, with cost cap restrictions being their weapon of choice. MGU-H development is one of the biggest expenditures for engine manufacturers, if not the biggest. Should they eliminate one of their biggest money sinkholes, the financial restrictions could come into fruition a lot easier.
That’s not all. When you are dealing with something this expensive, you would also expect top notch reliability, right? Well, MGU-H gives you the opposite. As a component, it is extremely unreliable and has the potential to be one of the main failing components at any given Grand Prix. As mentioned, the MGU-H runs at 125,000 rpm. Now imagine that for a span of 2 hours. Painful, isn’t it?
Historically, MGU-H bearings have been one of the mainstays for a breakdown (infamously, the Honda MGU-H’s from 2017, as an example). Even temperature plays a considerable role in its performance. Add to that, MGU-H also reduces exhaust noise, which surely isn’t something anyone would want. What’s worse is that this being such an expensive instrument, it is really difficult to find applications on production cars.
Now, with the removal of MGU-H, FIA is inviting new engine manufacturers to the game. Lesser developmental expenditure means companies will have greater long term financial stability (or as they claim). With lesser complicated components as the MGU-H, the manufacture of these engines will become easier (relatively easier, that is).
Now that the MGU-H is removed, turbo lag is set to return. This would in turn make it difficult for the drivers to take control of their cars exiting any corner. That said, with an increase in electrical impact on the powertrain, constructors will most likely recuperate that lost ICE response with the instant electrical motor torque.
MGU-H had both pros and cons alike. To be fair, pros well outweighed the cons over the years; it would not have been in use otherwise. Had the green crispies not hindered as much these days, this would have still seen the light of day, including with the other technical revolutions like the 2020 DAS System of the Mercedes W11.
All in all, the MGU-H shall be fondly remembered among the technical nerd-heads like myself. On the bright side, we are getting Porsche (and perhaps Audi, too) as engine manufacturers in F1 so….. Hey, that’s also a win!
Formula 1 returns to track this weekend, at the Spa-Francorchamps for the Belgian GP after a month long summer break! Be sure to not miss out on our coverage and analyses every race weekend at our Motorsports section, and visit here for our other reviews!