UK-based Yasa claims world record with new 738bhp, 13.1kg motor
Firm says this is the highest-density motor ever built in any sector
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by Will Rimell
2 mins read
17 July 2025
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Mercedes-Benz-owned Yasa Motors has created what it claims to be the highest-density motor ever built – a 13.1kg unit that produces 738bhp.
That equates to 56bhp per kg, which is more than double the industry benchmark of 20bhp per kg. UK-based Yasa calls it an unofficial world record for motor power density – across any application or sector, not just automotive.
The electric motor with the highest power-to-weight ratio currently in production is the Equipmake HPM-400, which puts out 54bhp per kg. Weighing 40kg, the Australian-produced unit is used in aerospace and marine vehicles.
Yasa’s figures were reached during prototype testing last week. What makes the feat most remarkable, says Yasa, is that the unit uses no exotic materials such as cobalt-iron laminations and litz wire. Moreover, it was not created using 3D printing.
Tim Woolmer, Yasa CTO and founder, told Autocar: “This result is a glimpse of what’s possible when deep tech, R&D and practical engineering comes together. We’ve shown that you don’t need exotic materials or experimental manufacturing processes to achieve record-breaking performance.
“What we’ve achieved here is not just a number – it’s a demonstration of scalable, production-ready innovation that raises the bar for electric motor design. And the most exciting part? We’re just getting started.”
Once the unit is signed off, production can reach up to 50,000 units a year at its Oxfordshire plant, according to Yasa.
In a statement, the firm said: “While unofficial, this record represents a major milestone – not just for Yasa, but for what’s possible at the cutting edge of practical, high-performance electric motor design.”
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There are no official details about when a production version of the motor could be launched, nor what cars it will power. Yasa currently supplies motors to Lamborghini, Mercedes-AMG and Ferrari, among others.
