Renault R25: Remembering F1’s Final V10 Champion

Next year, F1 cars will adopt fresh hybrid turbo V6 power units, drawing a larger proportion of their energy from the electrical side despite the MGU-H being dropped and... yes, you’ve switched off already, haven’t you? Fair enough.

Talk that the lower-output engines could become slower along long straights once their batteries run flat has prompted plenty of unease over the direction of F1’s efficiency-fixated powertrain regulations. That is particularly true when today’s engines are the most thermally efficient combustion units in motoring history, while the 2026 grid will run solely on sustainable fuels. So why not return to lighter, simpler, cheaper V10s that shriek and spit flames?

Renault R25: the V10 era’s final champion

For a reminder of what has been lost, look no further than the sublime 2005 Renault R25. Fernando Alonso drove this tiny, pin-sharp projectile to the last Formula One world championship won by a V10-powered car. It highlights everything modern F1 often gets wrong: it is slim, nimble and short in wheelbase, with aerodynamic elements that are detailed rather than forced. There is no overtaking-button boost and no DRS, either. Its livery is pretty decent too. In fact, it appears to share more with a local arrive ’n’ drive kart than with today’s swollen F1 field.

Renault RS25 engine and performance

Mounted at ankle level is the 72º 3.5-litre Renault RS25. It reaches 19,000rpm and produces 900+bhp while weighing under 100kg. That gives the complete car 1,500bhp per tonne – over twice the power-to-weight ratio of a Bugatti Chiron. It is a miniature engineering masterpiece, as you would hope when every engine cost £170k.

The R25 was not a dominant clean-sweep machine. Across its season, it actually lost the outright victories contest to McLaren by 10–8, yet it was dependable and consistent, failing to score points at only two events. When Alonso got back behind its wheel at the 2021 Abu Dhabi Grand Prix, the two time champion described it as “small, like a toy, but very special” and is said to have lapped the circuit faster than any of the officially timed laps recorded in the race the next day.

Top Gear’s Renault R25 appearance

This car also has Top Gear pedigree. It was not the car that demolished the track in 59 seconds – that was the R24, its direct predecessor. However, the R25 featured in series eight, episode 10, where Richard Hammond illustrated how alien F1 performance feels to an ordinary human by attempting to drive it. He spun off after half a lap.

The word is that Mercedes, Audi and Honda would rip up their F1 engine supply agreements if V10s replaced hybrids, because they would no longer have road relevance. Don’t let the pit-garage door hit you on the way out...

Renault R25

Price new (2005): £5m
Price now: £500,000
Engine: 3,000cc V10, 900+bhp @ 19,000rpm, 324Ib ft @ 16,400rpm
Transmission: 6spd semi-auto, RWD
Performance: 0-62mph in 2.0secs (est), 210mph
Weight: 605kg

Photography: Jonny Fleetwood & Alex Tapley