This is our favorite sort of automotive history lesson—a Lotus Esprit Turbo fitted with a pioneering active suspension system that is set to be auctioned next weekend. It is proof of just how far ahead of the curve Lotus was in the early 1980s, but also a reminder of what a handsome car the wedgy Esprit Turbo is, especially when wearing the same black and gold color scheme as Lotus’s Formula 1 cars of the era.
Lotus was one of the first teams to use active suspension in motorsport, developing it for Formula 1 where the need to control ride height was critically important for the ground effects aerodynamics that turned the underside of the car into a wing element. The Type 92 that Lotus raced in the 1983 Formula 1 season used an active hydraulic suspension system to control height as downforce levels increased. The Type 92 was out-gunned by turbocharged rivals and never got close to winning a race, but active suspension would be developed by Lotus and other F1 teams until it was banned in 1994.
According to contemporary reports, this 1980 Esprit Turbo was used as a test mule for that first Formula 1 system, using hydraulic pistons driven by an engine-powered pump to replace its conventional springs and dampers. Sensors on each corner detected loads and ordered the pistons to react to smooth bumps and dips. Accelerometers allowed the computer-controlled system to also measure lateral and longitudinal acceleration and therefore counter roll, pitch, and dive by sending different amounts of pressure to each end or side of the car. As one British magazine described it, after experiencing the car on Lotus’s Hethel test track, “imagine the super soft, pitch-free ride of a Citroen CX with a standard of cornering grip to embarrass a Lamborghini Countach.”
That last claim was far from hyperbole. In its most aggressive zero-roll guise, the Esprit prototype could reportedly deliver up to 1.5G of lateral cornering on period Goodyear NCT road tires. The system had other functions, including the ability to counter-roll and lean the car into corners like a bicycle—this being the same function that Mercedes describes as "Curve mode" 40 years later. The suspension system’s pistons only worked when pressurized by the pump, with the car sitting a hellaflush four inches lower than a standard Esprit when the engine was turned off. The hydraulic pump was also reported to sap up to 10 hp from the motor’s 212-hp peak.
For a fuller explanation of the system, and a demonstration of how it compared to a standard, steel-sprung Esprit Turbo, check out this YouTube review by John Miles, himself a former Lotus Formula 1 driver and development engineer, also later a part-time jazz record label boss.
After the project finished, the prototype Esprit stayed at Hethel for many years, reportedly being saved from the junkyard on several occasions. In 2015 it was sold to a private collector and had to be removed from an office a Hethel sideways through a pedestrian door. Since then, much of the car has been restored, at a reported cost of £60,000 or $76,000 at current exchange rates, and is now driveable. That work included a rebuilt engine and gearbox, wiring, and brakes, but didn’t include getting the active suspension working again, something that would require the full recommissioning of the system’s computer control system and actuators.
The Esprit prototype is going to be auctioned by Anglia Car Auctions where it will be one of the headline lots of a sale that will run across January 27 and 28. It carries an estimate of between £90,000 and £120,000. That’s $115,000 to $152,000, with commission of six percent on top of that. You can find out more, or register to bid, here.
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