Lotus designed hydraulics, and the car would have been $150,000 in 1990.
The Chevrolet Corvette C4 began to look tired after a few years. In 1990, the ZR-1 was released. It featured a Group Lotus-designed aluminum block 5.7-liter V8 with dual overheadcams and four valves per piston. This gave it 375 horsepower (280kilowatts), and 370 pound feet (502 newton meters). Although it was a major technological upgrade to the Vette engine and the iron-block V8, the modifications didn’t end there.
The ZR-1’s wider rear track allows for larger tires. It came standard with the FX3/Z51 performance suspension. This includes adjustable dampers and sport tuned springs, along with thicker anti-roll bars. These results were impressive, with incredible grip and reasonable handling on good pavement. It could have been better.
This rare 1990 Corvette ZR-1 Active Suspension prototype is now available. Built using yet more input from the Lotus engineering firm, the experiment made use of hydraulic-controlled dampers and a sophisticated-for-its-time Delco computer system, which firmed up the suspension in corners using lateral g-meters to counteract body roll. It could also respond to road bumps almost instantly, smoothing out C4’s notoriously fragile ride quality.
One of the problems was heat. The car was fitted with cooling vents on the front and a dedicated cooler to cool the hydraulic fluid. Due to the high pressure required by the fluid (3,000 pounds per square inch), durability was also an issue. This was more difficult to resolve. Electronic interference was also a problem because the dynamic sensors are so sensitive.
General Motors spent $27 million on Active Suspension before it was scrapped for several reasons. First, technology wasn’t up to the mark. The on-wheel accelerometers interacted with the highly sensitive suspension actuators. Insulating transducers that would have solved the problem wouldn’t be available for at least a decade. The Active Suspension would have cost the ZR-1 an enormous amount of money – somewhere between $35,000 to $100,000 per car. This is a significant sum considering that the ZR-1 was about $60,000.
A decade later, the Corvette C5 would have Magnetic Ride Control. This was the precursor to today’s system. It solved some Active Suspension issues without increasing the cost. The name refers to magnetorheological particles found in the dampers. They can soften or firm up depending on magnetic force. This makes the Corvette more comfortable on rough roads without losing its composure. Delphi designed MRC instead of Lotus. This makes the system a little less exotic than that found on the C4 ZR-1. Who wants a badge saying “Handling by Delphi?”
Chevrolet produced 25 prototypes using the kit in 1990. Four of those models are still available. This vehicle is one of four that was built in 1990. It was sold by Hemmings in Miami for $89,000 and has 12,381 miles. The original price premium on regular C4 ZR-1s is about $50,000, and the excellent condition of this vehicle makes it attractive to collectors. However, the rareness of any 1990 Corvette with such low mileage should make the experimental suspension even more appealing. Even though the vehicle is described as running and driving well, future maintenance may be necessary.
If you still want to enjoy the best performance 1990s GM has to offer, grab your checkbook and book a flight to the Sunshine State.