AC Propulsion tzero

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The AC Propulsion tzero with the top off

The tzero is a hand-made electric sports car produced by the U.S. company AC Propulsion. It is based on the Piontek Sportech kit car. The tzero uses a reinforced steel space frame, double wishbone independent suspension, rack and pinion steering, AC-150 drivetrain, a fiberglass body, and a single overall gear ratio of 9:1.

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.

New Lithium Ion battery pack

The version debuted by AC Propulsion in August 2003 is powered by 6,800 lightweight lithium-ion cells, similar to those that make up the battery packs of laptop computers, giving it a 300 mile (480 km) range. Lighter than the original version by 700 pounds (320 kg), the 2003 edition goes from 0-60 mph in 3.7 seconds. The single gear ratio limits the car's maximum velocity to just over 140 mph (225 km/h) at 13,000 rpm with proper gearing, though it has never been tested at greater than 105 mph (169 km/h). The base price of the car is USD $220,000.

Original Lead-Acid battery pack

The original version of the roadster runs on 28 Optima Yellow Top Lead Acid batteries which produce 200 horsepower (150 kW) and 177 lbf·ft (240 N·m) of torque at 336 volts which rockets the 1040 kg car from 0 to 60 mph in 4.07 seconds. The single gear ratio limits the car's maximum velocity to 90 mph (145 km/h) at 12,000 rpm, although it is said that early prototypes fitted with multiple gear ratios could hit 155 mph (250 km/h). Even still, it is capable of completing a quarter mile (400 m) drag race in 13.24 seconds. The expected range per charge of the tzero with the batteries it comes with is 80 to 100 miles (130 to 160 km) as a result of consuming only 180 watt hours per mile (895 J/km) (DC) on the highway and due to regenerative braking. Within a single hour, the car can be charged from 0-95%. The base price of the car due to low volume production is USD $80,000.

ACP Backtracking Genset trailer

AC Propulsion also has a backtracking, range extending, gas fueled trailer, making it a gas-electric series hybrid. The trailer used a 500 cc Kawasaki engine with a 9.5 U.S. gallon (40 liter) fuel tank and achieved 30 to 35 mpg over at least 20,000 highway miles. It is rated at 20 kW DC output and can maintain 60 to 80 mph. Video footage of the backtracking feature, which allows drivers to easily back a trailer through a set of slalom cones, can be seen at [1].

The name comes from t₀, the mathematical symbol for a starting point in time.

Due to high production costs, however, AC Propulsion ceased to produce the tzero. Three were produced (although the company website claims that a fourth one is currently under production), one of which is owned by the company itself and the other two were sold. Some of the technologies developed for the tzero live on in the Venturi Fetish, the Wrightspeed X1, and in modified form in the Tesla Roadster.