The tzero is a handmade electric sports car designed and built in very limited numbers by the U.S. company AC Propulsion. The tzero was based on the Piontek Sportech kit car, which consists of a fiberglass body built over a reinforced steel space frame with double wishbone independent suspension and rack and pinion steering. AC Propulsion added the AC-150 drivetrain, a single-speed electric system with an overall gear ratio of 9:1. Launched in January 1997, only three prototypes were built and plans for commercial production were dropped in mid-2003. The name comes from t0, the mathematical symbol for a starting point in time. Due to high production costs, AC Propulsion ceased to produce the tzero. Only three were built,[ one of which is owned by the company itself, one by Gruber Power Services, a company that specializes in Tesla Roadster repair, and one privately. The drivetrain, however, was used in many other vehicles. Because the car recharges its batteries when the throttle is released — slowing sharply as energy is recaptured — it can be driven hard using only the accelerator pedal. Also, if the car detects a turn with more than half a g-force (5 m/s²), it eases the rear-wheel regenerative braking to prevent slides.
AC Propulsion tzero, The Godfather of Modern EVs
If you had to write a book on the history of the rebirth of the modern EV, the AC Propulsion tzero would stand prominently in the pantheon as the EV that restarted it all. It came from AC Propulsion, a unique company with incredible folks hard at work making EVs better all the time — doing what they loved to do best.
Martin Eberhard wondered why there weren’t cool modern cars with more efficient energy systems than the pushy, but ultimately highly inefficient internal combustion engine (ICE). Thankfully, someone mentioned to check out a company called AC Propulsion, located near Los Angeles. There he found engineers doing incredible work on controllers and electric motors. What he saw that would truly change the landscape of the automotive industry — three units of the little yellow electric rocket called the tzero.
AC Propulsion was really not interested in building electric cars, to Martin’s dismay. In fact, the company produces drive systems, battery management systems, vehicle management systems, and vehicle-to-grid systems for OEMs. Back then, the company was content tweaking electric systems, designing better controllers, and grooved on oscilloscopes and sine waves. So, Martin rightfully thought, why not make his own EV and use AC Propulsion components.