The average powertrain output has risen by almost 29% over the past 20 years despite engine capacity falling by nearly 8%, according to analysis by Vehicle Data Global.
The data specialist said average output increased to 148bhp between 2005 and 2025 while average engine capacity declined by 7.8%, from 1,771cc to 1,633cc.
It means many modern family cars now produce power comparable with performance cars and hot hatchbacks from previous decades.
VDG highlighted the 150PS Skoda Octavia 1.5 TSI e-TEC mild hybrid, which produces power comparable with the Vauxhall Astra GSi and Renault Clio Williams of the 1990s despite its smaller engine.
The 158PS Nissan Qashqai 1.3 DIG-T mild hybrid produces about 156bhp, exceeding the output of the six-cylinder 2.5-litre Triumph TR6 PI.
More power from smaller engines
Average power per litre increased by 42.9% over the period to reach 69.1kW per litre, reflecting the contribution of turbocharging and electrified powertrains.
VDG cautioned that the reported output for hybrid vehicles includes assistance from electric motors and does not represent combustion-engine power alone.
Median engine capacity fell from 1,599cc in 2005 to 1,498cc in 2025 while median power increased from about 107bhp to 138bhp.
VDG used 134bhp, equivalent to 100kW, as its performance benchmark. In 2005, about 8,500 cars with engines of 1.5 litres or smaller met or exceeded that output, accounting for 0.4% of registrations.
By 2025, the figure had grown to 444,000 vehicles or 26.7% of registrations.
Ben Hermer, operations director at VDG, said: “Nothing illustrates the engineering success of modern car makers better than our analysis of powertrain output increases from ever-shrinking engines over the past 20 years.
“They did this by an ingenious combination of turbocharging and introducing new contributions, in the form of hybrid technology.
“Back in 2005, getting 134bhp+ from a 1.5-litre-or-smaller engine was unusual, whereas now more than one new registration in four offers that advantage.”
Engine downsizing reaches plateau
The share of registrations powered by 1.0-litre engines increased from around 3.3% in 2005 to a peak of 18% in 2020 before falling back to 14.5% in 2025.
VDG said the wider reduction in engine capacity now appeared to be levelling off. Average capacity changed comparatively little between 2019 and 2025, falling from about 1,645cc to 1,633cc, while average output continued to rise from 105kW to 111kW.
Hermer said: “Car makers faced increasingly stringent regulatory pressures as governments focused on reducing emissions and they responded with a combination of engine downsizing, turbocharging and the introduction of electrical motor assistance.
“In the process, they radically changed the relationship between engine size and performance. The old intuitive assumption that a 2.0-litre car is inherently more powerful than a 1.5 is no longer true.
“Cutting emissions without sacrificing performance was a difficult challenge but they achieved more than that, by achieving major improvements at the same time.
“All of this suggests that it might be time to abandon the old adage that there is no replacement for displacement.”
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