It is a familiar sight on drag strips: a modern electric sedan lining up next to a traditional combustion supercar. The green light drops, and the EV instantly puts multiple car lengths on its gas-powered rival. But if the runway is long enough to push past 150 mph, the narrative shifts. The internal combustion engine (ICE) begins to claw back its lead, ultimately passing the EV.
This discrepancy isn't a fluke. It is a direct result of electric motor physics, a phenomenon called Back EMF, and the engineering limitations of single-speed transmissions.
Why EVs Rule the Launch
To understand why EVs dominate from 0 to 60 mph, we must look at how motors produce torque. An internal combustion engine must build RPM to reach its peak volumetric efficiency. Even with modern launch control, anti-lag systems, and dual-clutch transmissions, there is a physical delay while the engine sweeps through its rev range and turbos spool.
An electric motor, conversely, produces maximum torque at zero RPM. The moment current flows into the stator, the magnetic forces act instantly on the rotor.
Furthermore, electric torque can be adjusted thousands of times per second. While an ICE traction control system must cut fuel or retard ignition timing—a relatively slow physical process—an EV adjusts current almost instantly. This allows cars like the Lucid Air Sapphire or Tesla Model S Plaid to apply maximum power precisely at the limit of tire adhesion, yielding sub-two-second 0-60 mph times.
The High-Speed Wall: Back EMF
As speeds climb past 100 mph, the electric motor's greatest strength becomes its limitation. This is due to a physical law known as Back Electromotive Force (Back EMF).
As an electric motor spins, the rotating magnetic fields generate their own voltage inside the motor's copper windings. This self-generated voltage opposes the incoming voltage from the car’s battery pack. The faster the motor spins, the higher the Back EMF becomes.
Eventually, at high RPM, the Back EMF nearly equals the battery's supply voltage. When this happens, the motor cannot draw enough current from the inverter to produce high torque. While a high-performance V8 is breathing deeply and making peak horsepower at high RPM, an EV's torque curve is actively decaying.
The Multi-Ratio Advantage
The second half of the equation is gearing. To save weight, cost, and mechanical complexity, most EVs use a single-speed reduction gearbox. This gear ratio must be a compromise: short enough to provide aggressive acceleration from a standstill, but tall enough to cruise at highway speeds.
At 150 mph, a single-speed EV motor is spinning near its physical limit—often upwards of 16,000 to 20,000 RPM—where efficiency and torque are at their lowest.
An ICE vehicle utilizes a multi-speed gearbox, typically with 7 to 9 speeds. This allows the engine to drop back into its optimal power band at high speeds. When a Porsche 911 Turbo S shifts into 5th or 6th gear at 150 mph, it drops its engine RPM back into its peak horsepower range, allowing it to continue pulling hard. Porsche addressed this in the Taycan by using a unique two-speed rear gearbox, proving that multi-speed setups are necessary to bridge the high-speed gap.
The Bottom Line
EVs are unmatched sprinters because of instant torque and high-speed traction management. However, physics dictates that as speeds push past 150 mph, the combination of Back EMF and single-speed gearing hands the advantage back to combustion engines.
Curious to see how weight, horsepower, and gearing affect real-world acceleration? Run your own matchups on our drag-race simulator to test the limits of EV torque versus ICE gearing.