Manufacturers discovered the relative limitations of a naturally aspirated engine long ago. Typically, engine builders turn to turbocharging when they want colossal horsepower-per-liter figures. They know that if they force enough air even into a relatively small engine, the unit can make once-absurd outputs attainable. However, Gordon Murray Automotive decided to remain old-school and pursue something remarkable instead. Soit went to the best, working with Cosworth on the T.50, and the unit became the most power-dense naturally aspirated road-car engine ever seen.
Gordon Murray’s T.50 super car follows the same recipe that turned the McLaren F1 into the legend it is. Low weight, excellent driving dynamics, and a naturally aspirated V12 engine behind the seats, driving the rear wheels.Gordon Murray Automotive
In August 2020, Gordon Murray Automotive (GMA) announced that its upcoming T.50 supercar would have a 661-hp V12 engine from Cosworth. Specifically, the unit displaced 3,994 cc and could spin up to 12,100 rpm. Other impressive numbers included a weight of just 392 pounds. The powerplant made 353 lb-ft of torque at 8,000 rpm. It would also drive the rear wheels through a six-speed manual transmission.
Cosworth’s achievement becomes even more formidable when you consider that there were no turbochargers to push more oxygen into the cylinders, or any electric motor to contribute to the quoted combustion engine output. Instead, Cosworth had to generate that horsepower through a conventional internal combustion approach, even if it pushed those fundamentals to the extreme.
To achieve the company’s goals, Cosworth and GMA engineers focused on airflow, combustion efficiency, a lightweight valvetrain and reciprocating components, and engine speed. All of this came in a genuine production road car, even if there would be only 100 examples of the T.50. GMA produced the vehicles at its new Highams Park facility, a 54-acre technology campus in Windlesham, UK, and all were customer cars rather than track-only specials.
The 12,100 RPM Red Line Explains A Lot
The GMA Cosworth V12 from the T.50.Gordon Murray Automotive
In simple terms, horsepower depends on torque and engine speed. The T.50 V12 architecture showed how it could make so much power from so little displacement. It had an 81.5 mm bore and a very short 63.8 mm stroke, together with a 14:1 compression ratio. This differs greatly from something like a large-displacement, low-speed V8, where engineers design it to generate performance through low-rpm torque. Instead, the GMA engine could breathe and survive at remarkable rotational speeds. Its rev limit was 12,100 rpm, with peak power coming in at around 11,000 rpm.
The engine’s response is probably more extraordinary than its maximum rpm. According to GMA, the V12 can gain 28,400 rpm per second under unloaded conditions. It also says that it can sweep from idle to the limiter in roughly 0.3 seconds. This may explain why GMA focused on reducing rotational inertia instead of merely maximizing peak horsepower.
The engine also uses gear-driven ancillaries instead of conventional accessory belts. In addition, there’s an induction system that feeds through a roof-mounted ram-air inlet and four throttle bodies. The powerplant delivers 71% of its maximum torque to the driver from only 2,500 rpm, while the torque peak doesn’t arrive until 8,000 rpm. And while Cosworth built an engine that didn’t simply work between 9,000 rpm and its limiter, GMA still had a challenge on its hands. It had to combine this exotic engine with enough flexibility to make the T.50 usable as an extreme driver’s car that functioned on the road.
Cosworth Also Made The Entire V12 Weigh Just 392 Lbs
The GMA Cosworth V12 from the T.50.Gordon Murray Automotive
GMA liked to quote superlatives when showing off its engine, and since this V12 weighed only about 392 pounds, it called it the “lightest naturally aspirated road-going V12 ever seen.” That fit perfectly with Murray’s broader philosophy for the T.50: instead of compensating for weight by packing in more horsepower, GMA developed the car with reduced mass firmly in mind. The T.50 weighs just 2,198 pounds, despite its V12 engine, three-seat cabin, and road-car equipment.
The engine used aluminum, steel, and titanium where strength and weight mattered most, and it was semi-structural rather than simply hanging from conventional mounts. This helped engineers capture some of the stiffness and mass advantages of a race car without imposing the vibration and noise penalties that might have emerged if they’d made the engine fully structural. The engine’s net weight makes its story even more remarkable. After all, power density alone can hide compromises. Something that can theoretically achieve an extraordinary horsepower-per-liter figure can often be too heavy, fragile, or peaky for ordinary road use.
Even The Aston Martin Valkyrie’s V12 Can’t Match It Per Liter
2023 Aston Martin Valkyrie 6.5L Cosworth RA NA V12 EngineAston Martin
To put GMA’s achievement in context, it helps to benchmark the powerplant against another engine with significant Cosworth input. Here, the Aston Martin Valkyrie with a 6.5-liter naturally aspirated V12 engine is much more powerful overall than the GMA creation. Aston Martin originally certified it at 1,000 hp at 10,500 rpm and gave it a maximum engine speed of 11,100 rpm. However, the manufacturer rated its specific output at 153.8 hp per liter. That means the T.50, at approximately 165.5 hp per liter, comes out ahead, even though it gives up nearly 340 hp in total output.
Other conventional benchmarks seem to emphasize the gap even more. For example, the 4.0-liter naturally aspirated flat-six in Porsche’s 992-generation 911 GT3 RS produces 517 hp, which represents 129.25 hp per liter, with an engine revving to 9,000 rpm. While that may be heady stuff by ordinary road-car standards, that rev ceiling is still more than 3,000 rpm below the T.50.
The Chevrolet Corvette Z06 is worth a look, too, but Chevrolet takes a different route. That car’s 5.5-liter LT6 flat-plane crank V8 produces 670 hp at 8,400 rpm with 460 lb-ft at 6,300 rpm. This makes it the most powerful naturally aspirated production V8 in history, according to Chevy, yet it produces about 121.8 hp per liter. The Ferrari 458 Speciale also represents an astonishing achievement in itsera. The 4,497 cc naturally aspirated V8 produced 598 hp at 9,000 rpm, which is roughly 132.8 hp per liter.
So, the T.50 wins the battle by facing up to some of the most sophisticated naturally aspirated production engines in very special cars like the Valkyrie, GT3 RS, Corvette Z06, and 458 Speciale.
Base Trim Engine
4.0L V12 Gas
Base Trim Transmission
6-speed Manual
Base Trim Drivetrain
Rear-Wheel Drive
Base Trim Horsepower
656 hp
Base Trim Torque
344 lb-ft@9,000 rpm
Fuel Economy
TBC
Infotainment & Features
8 /10
The Track-Only T.50s Shows What Happens When Road Car Rules Come Off
Gordon Murray Automotive T.50s Niki Lauda Chassis 1 Production CarGordon Murray Automotive
When GMA took the T.50 from the road and placed it on a track, it raised even more eyebrows. The special T.50s, named after Formula One World Champion Niki Lauda, kept the same basic engine architecture but were substantially reworked with different cylinder heads, camshafts, a higher compression ratio, and a freer-flowing exhaust. This car also had a paddle-shifted Xtrac transmission, unlike the road-going version.
GMA reckons that the T.50s produced as much as 762 hp while still retaining the 12,100 RPM limit. And this shows what the company could achieve by removing road homologation, maintenance, and usability constraints. After all, the standard T.50 still had to deliver its particular performance while maintaining its duties as a road car, with a manual transmission, usable torque, and suitable refinement.
In the end, Gordon Murray decided not to follow the rest of the hypercar industry and move towards turbocharging or hybrid combinations. Instead, he worked with Cosworth to pursue something far harder to quantify from a simple spec-sheet headline. His team chased response, low mass, revs, and mechanical connection, and the result was an engine that set records. It may have only made a fraction of the power of today’s most extreme turbo-hybrid hypercars, but it needed less than 4.0 liters and no forced induction to come up with its 661 hp.
Sources: Gordon Murray Automotive, Aston Martin, Porsche, Chevrolet.
