Modern performance engineering has reached a point where tiny engines can produce outputs once reserved for much larger powerplants. But impressive numbers alone do not guarantee that buyers will embrace the technology behind them – look, for example, at the Mercedes-AMG C63 E Performance with its four-cylinder engine.
The hypercar market makes this especially clear. Its customers can afford the most radical engineering available, yet they are not necessarily willing to give up the characteristics that have traditionally made exotic cars desirable. That creates an intriguing contradiction: An engine can be extraordinarily sophisticated, efficient and powerful, yet still lose out to a more conventional alternative when buyers are given the choice.
Why Making A Small Engine Powerful Is The Easy Part
Aramco Dedicated Hybrid Engine 1.6L Three-CylinderAramco
Turbocharging, direct fuel injection, variable valve control and hybrid assistance have transformed what engineers can extract from relatively small internal combustion engines. Forced induction allows manufacturers to push more air into compact cylinders, while sophisticated combustion management can optimize fuel delivery and ignition with remarkable precision. Electrification can then fill in the gaps, providing instant torque while allowing the combustion engine to operate closer to its most efficient range.
The BMW i8 hybrid is powered by a combination of a turbocharged three-cylinder engine and an electric motor.BMW
But raw power density tells only part of the story. An engine producing extraordinary horsepower from a small displacement still has to deliver predictable throttle response, acceptable emissions, reasonable fuel consumption and the durability expected of a production vehicle. It also has to manage heat, boost pressure and mechanical stress without becoming impossibly complex or fragile.
That is where downsizing becomes much more difficult. Making a small engine powerful is one challenge. Making it powerful, responsive, efficient, clean and durable at the same time is an entirely different engineering exercise.
Mercedes-AMG C63 S E Performance M139 And Plug-In Hybrid SystemMercedes-Benz
Koenigsegg’s answer to that problem was an engine that breaks nearly every conventional rule – starting with the number of cylinders.
The Three-Cylinder That Thinks Differently
Koenigsegg Tiny Friendly Giant (TFG) 2.0 three-cylinder with FreevalveMáté Petrány/CarBuzz/Valnet
Founded in Sweden in 1994, Koenigsegg has built its reputation around engineering solutions that challenge conventional thinking. The company produces cars in extremely limited numbers, allowing it to pursue technologies that larger manufacturers might consider too complex or costly. That philosophy has made Koenigsegg one of the most technically ambitious names in the hypercar world, which brings us to another of its technical highlights.
Koenigsegg Gemera, rear profile viewVia: Koenigsegg
Calling its TFG engine (short for Tiny Friendly Giant) a “three-cylinder” undersells what Koenigsegg created. The 2.0-liter twin-turbo inline-three produces 600 horsepower and 443 lb-ft, with peak power arriving at 7,500 rpm and the engine continuing to an 8,500-rpm redline. That works out to an impressive 300 hp per liter. But perhaps the stranger statistic is found inside the block. At roughly 667 cc per cylinder, each of its three cylinders is actually larger than the approximately 625 cc cylinders in Koenigsegg’s 5.0-liter V8.
This engine is also remarkably compact. Its 95 mm bore and 93.5 mm stroke give it substantial cylinder dimensions despite the modest overall displacement, while its magnesium-alloy construction and dry-sump lubrication help keep the engine’s weight to 154 lbs.
The result is an engine with proportions almost as remarkable as its output. Three large cylinders, two turbochargers and enough mechanical strength to spin beyond 8,000 rpm are packed into a powerplant weighing little more than some complete engines from ordinary performance cars.
Koenigsegg Gemera powertrain, view of drivetrain closeup and all partsVia: Koenigsegg
The TFG’s unusual dimensions are therefore not merely a consequence of downsizing; they are central to how Koenigsegg approached the problem.
It Doesn’t Need Camshafts At All
The valvetrain cover for the Koenigsegg Freevalve engine concept.Freevalve
The TFG’s defining innovation is its Freevalve valvetrain, which replaces the conventional camshaft with electro-hydraulic-pneumatic actuators and sensors. Each intake and exhaust valve can be controlled independently, allowing its timing, lift and duration to be varied according to what the engine needs at any given moment. That removes the compromises inherent in a fixed camshaft profile and means the valves themselves can regulate airflow, eliminating the conventional throttle body and its associated pumping losses.
The system also enables per-event cylinder deactivation, allowing individual cylinders to be shut down when they are not needed rather than relying on predetermined deactivation patterns. According to Freevalve’s technical description, this contributes to a claimed 15–20% reduction in fuel consumption compared with a conventional 2.0-liter four-cylinder engine using direct injection and variable camshaft timing.
Technical images of how Freevalve camless valvetrains workFreevalve
Freevalve also makes the TFG’s unusual sequential twin-turbo arrangement possible. Each cylinder has two exhaust valves, with one valve initially directing exhaust gas toward the smaller turbocharger. Once sufficient boost is established, the second valve opens, bringing the larger turbocharger into the system.
Mazda Spirit Racing Roadster and Mazda Spirit Racing Roadster 12RMazda
The same valve control is useful before the engine is properly running. During cold starts, the system manipulates the intake and exhaust valves to increase turbulence and heat the combustion process, helping the catalytic converter reach operating temperature faster. Koenigsegg and Freevalve claim this can reduce cold-start emissions by around 60% compared with a conventional camshaft-equipped engine.
With 600 hp, camless flexibility, and a 60% emissions advantage at cold start, the TFG should have been exactly what the Gemera needed. So why did Koenigsegg eventually pull it from production?
The Hypercar Buyers Chose A V8
Koenigsegg Gemera. 5.0-liter twin turbo V8Koenigsegg
For all its engineering ambition, the TFG ultimately encountered a problem that no dyno test could solve – buyers did not want it badly enough. By late 2024, Koenigsegg had shelved the three-cylinder powertrain for production versions of the Gemera after customers overwhelmingly favored the company’s twin-turbo V8 instead. The decision was not an admission that the TFG failed technically. It was a commercial verdict from the very customers the engine was designed to impress.
The engine bay of the Koenigsegg Sadair’s SpearMáté Petrány/CarBuzz/Valnet
That preference is revealing because hypercar buyers are purchasing far more than acceleration figures. A V8 brings a different character, sound, and sense of occasion, while its greater cylinder count carries an emotional significance that specifications cannot quantify. The irony is particularly sharp here.
Customers spending vast sums on cutting-edge technology still showed a preference for a more familiar form of exotic-car engineering. Koenigsegg’s current Gemera specification reflects that decision, with the 5.0-liter twin-turbo Hot-Vee V8 paired with the Dark Matter electric motor to produce a combined 2,300 hp.
2011 Koenigsegg Agera exteriorKoenigsegg
The TFG therefore represents something more nuanced than a failed experiment. Its engineering case was extraordinarily strong, but the showroom exposed a limitation that no efficiency gain or clever valve system could overcome. When customers are buying a hypercar, emotional appeal can matter just as much as engineering efficiency.
The Engine Hypercar Buyers Rejected Could Reshape Mainstream Performance
Koenigsegg Gemera First Customer DeliveryKoenigsegg
The TFG may have lost its place in the Gemera, but that does not make its underlying technology a dead end. Freevalve has spent years developing and demonstrating camless valvetrains, with the technology intended to give engineers far greater freedom over how a combustion engine operates. Its significance therefore extends beyond the headline output of one unusual three-cylinder. By removing the fixed relationship between the camshaft and valves, Freevalve opens up different possibilities for combustion, airflow and engine control.
Koenigsegg Tiny Friendly Giant Engine, closeup Koenigsegg
That makes the TFG an important proof of concept. It demonstrated that this approach could be applied to a high-output automotive engine rather than remaining a laboratory curiosity. More importantly, it showed that extraordinary power density could coexist with a compact combustion engine without relying simply on ever-increasing displacement. The technology could consequently become more valuable as manufacturers face increasing pressure to extract greater efficiency from internal-combustion powertrains.
The same resistance to downsizing has appeared elsewhere in the performance-car world. Mercedes-AMG’s decision to replace the previous C 63’s V8 with a 2.0-liter turbocharged four-cylinder hybrid in theC 63 S E Performancedrew considerable criticism from enthusiasts, demonstrating that electrification and headline performance figures cannot necessarily replace the appeal of a larger engine. In some performance segments, buyers simply want the character and emotional connection that comes with more cylinders.
Koenigsegg CCGT1Koenigsegg
Freevalve’s own stated ambition goes considerably further than a single Koenigsegg application. The company says it is working with OEMs and Tier 1 suppliers to make its technology commercially available and scalable, while pursuing applications beyond Koenigsegg.
That may ultimately prove to be the TFG’s greatest achievement.
The three-cylinder itself might not have won over hypercar buyers, but the technology behind it could have a much longer life. If combustion engines remain relevant under increasingly demanding efficiency and emissions requirements, the engine that customers rejected could ultimately influence the engines they accept in the future.
Sources: Koenigsegg, Freevalve, Mercedes-AMG
