General Motors has experimented with a lot of wacky technology over the years, some of which it probably should’ve stuck with. The EV1 is probably the most famous example, but there are a number of other oddities that, although impressive at the time, never quite panned out. Active suspension is one of those concepts.
Yes, we have GM’s impressive Magneride system today, but when hydraulic suspension was all the rage in Formula 1 back in the 1980s and ’90s, the automaker teamed up with Lotus to try and make such a complex technology work on a production car. Long story short, it never really made it, but some of the prototypes equipped with this system still survive today. In fact, one of them that managed to escape GM’s Heritage Collection just popped up for sale on eBay.
The car, a 1990 Corvette ZR1, is one of only three known surviving prototypes with the system that wasn’t crushed, per the listing. Beyond its rarity, though, the system itself is undoubtedly interesting, so let’s talk about it.
To be clear, this is very much a prototype. The system never quite worked right despite the millions spent developing it, and it’s unclear how well it works on this particular ZR1. That doesn’t mean it’s totally inoperable, of course. As previously mentioned, it was developed with help from Lotus, who contributed significantly to the regular ZR1 beyond this experimental suspension system after being bought by GM in 1986.
It works by directing hydraulic fluid from a central engine-driven pump to struts at each corner of the vehicle. The pump, operating at 3,000 psi, is mounted in the engine bay and sends fluid through several computer-controlled hydraulic valves. Steel braided lines then send the fluid to each respective strut. The decision on where to send the fluid is based on several parameters including speed, estimated tire load, throttle, and steering position.
The big issue was the tech to reliably operate such a system didn’t really exist in the 1980s when the car was developed. Due to a lack of the right sensors and an inadequate amount of computing power, the car worked but not very well. Couple that with fluid cooling issues, and the end product just wouldn’t have been reliable enough for use by regular Corvette owners.
That doesn’t mean a quick spin in this 375-horsepower prototype wouldn’t be fun on occasion, though. For $89,500, this ultra-rare prototype can be in your driveway—an interesting collaboration by a legendary sports car builder in Lotus and the ever-present automotive conglomerate, General Motors.
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