For Sale On eBay: An “Active Suspension” Prototype Corvette ZR-1 From The $27 Million Factory Program

This fourth generation Chevrolet Corvette ZR1 is 1 of 25 original “Active Suspension” prototypes. These cars were developed by General Motors in collaboration with Lotus, integrating hydraulically actuated computer-controlled suspension technology from the Lotus Formula 1 Team.

The cost of this project was in excess of $27 million USD and the technology that was developed was never integrated into production Corvettes due to cost – some reports indicate it could have raised the MSRP to over $150,000 USD per vehicle.

Fast Facts – The “Active Suspension” Chevrolet Corvette ZR1

• The “Active Suspension” ZR-1 Corvette was designed to be the first production car with active suspension in history. The computerized hydraulic system was developed from a similar system used by the Lotus F1 team – GM had bought Lotus in 1986 and thus acquired access to their technology.
• The suspension design used a big-pressure hydraulic system linked to a Delco computer that made thousands of calculations each second based on data from sensors recording speed, tire load, steering, throttle, and a number of other factors.
• The 3,000 PSI hydraulic system would shift pressure where needed to all but eliminate body roll and reduce oversteer or understeer.
• Ultimately the Active Suspension program would never make it into production, the technology needed for the sensors and other computerized systems couldn’t be mass-produced for an affordable cost at the time.

Active Suspension: How It Works

Though it sounds complex the fundamentals of the C4 ZR-1 Corvette’s Active Suspension system are relatively to understand – a series of sensors feed data into an onboard computer that then sends hydraulic fluid in very precise amounts to the four hydraulic suspension struts, one at each wheel.

Above Video: This clip from 1987 gives a look into the hydraulically actuated computer-controlled active suspension system that was used on the Lotus 99T Formula 1 car. It would be a variation of this that was developed for the 1990 Corvette ZR-1 – watch till the end to see the Corvette get a mention.

The system allows pressure to be increased on the outside suspension and decreased on the inside suspension when cornering, helping to reduce or eliminate side-to-side body roll. Similarly the system could reduce forward-backward body roll when braking or accelerating.

The system developed by Lotus and GM engineers for the 1990 Corvette ZR-1 was fully functional and highly effective, the downside was that it was very expensive which made it unsuitable for mass-production at the time.

Many of the same GM engineers who worked on this active suspension system would later develop the Active Handling system used from 1996 onwards. By the early 2000s the technology had advanced even further and GM introduced Magnetic Selective Ride Control on the 2003 Corvette.

From the outside there are no indications that this is the rarest of the ZR-1 Corvettes – some believe that of the 25 original Active Suspension prototypes just two have survived.

The Active Suspension Corvette Prototypes

In the late 1990s GM was benefiting significantly from its acquisition of Lotus in 1986. Lotus was (and still is) a world leader in the field of handling and vehicle dynamics, and they had developed the LT5 V8 engine for GM – an advanced all-alloy V8 with double overhead cams per bank and 375 bhp.

While Lotus’ work on the LT5 is very well known in Corvette circles, their development of what would have been the first active suspension system on a production car for the 1990 ZR-1 is known by far fewer people.

Had the system been put into full production it would have been a major coup for Chevrolet and GM as a whole, beating the exotic supercar builders from Europe at their own game. It’s clear that GM executive believed in the project – enough to invest over $27 million dollars and set aside 25 ZR-1 Corvettes for it.

Very few, some say only two, of these original prototypes still exist today, and they’re highly sought after by collectors due to their historical significance.

This is the Lotus-developed LT5 V8, these engines were actually build by Mercury Marine. You can see the additional hydraulic systems on the left side of the engine, along with the associated hydraulic lines.

The 1990 Corvette “Active Suspension” Prototype Shown Here

The car you see here is one of the few original prototypes to have survived, this is largely due to the fact that it spend years on display in the GM Heritage Museum followed by the Corvette Museum.

Remarkably the car is now for sale on eBay of all places, the owner explains that it has 12,000+ miles on the odometer almost entirely from its original testing program with GM.

Under the hood (picture above) you can see some of the hydraulic system and its lines, and inside the car in the center console there’s a panel referencing the Active Suspension system, but it’s unclear if it can be switched on and off.

It’s described as being fully-fuctional and it’ll be up to the new owner whether they drive it, put it on display, or keep it tucked away in a private collection.

The Buy It Now price is $89,500 USD and you can click here if you’d like to read more about it or make the seller an offer.

Images courtesy of RMC Miami

The post For Sale On eBay: An “Active Suspension” Prototype Corvette ZR-1 From The $27 Million Factory Program appeared first on Silodrome.

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An Affordable Le Mans Classic Racer: The 1960s TVR Grantura

The TVR Grantura is a member of an increasingly rare subset within the classic car world – vehicles with impeccable period competition history that are still affordable enough to be bought by the average Joe. Or Josephine for that matter.

Over the decades TVR has developed a global reputation for building “proper” sports cars designed to go as fast as possible without the excess weight and complexity of things like ABS, traction control, or airbags. TVRs are purely analogue machines – if you crash one, it’s your own fault.

Fast Facts – The TVR Grantura

• The TVR Grantura was the first production car ever built by the Blackpool-based company. The first Grantura appeared in 1958 and the model was sold until 1967, spread across five generations from Mark I to Mark IV, and including the 1800S.
• The origin story of the name “TVR” is perhaps the single best-loved piece of automotive trivia in all of British history. The company was simply named by its founder – a man named Trevor. He took three letters out of his name and ran with it, creating an enduring sports car brand with a fiercely loyal fanbase.
• As TVR’s first production car, the Grantura set the standard for the many TVRs that would follow. The car has a lightweight fiberglass body, a tubular steel backbone chassis, and an engine and many other parts sourced from major automakers to help save costs.
• The car you see here is the Mark II version of the TVR Grantura, it’s powered by a 1600cc MGA engine fitted with a few go faster bits, power is sent to the rear wheels via a 4-speed manual transmission and a BMC rear axle.

Trevor + TVR

In the 1950s the western world was awash with low-volume car makers using fiberglass bodies, some variation of a tubular steel chassis, and bought-in engines, gearboxes, suspension, and brakes.

Though the car itself has been restored the interior has been kept largely original, so as not to remove decades of patina.

Very few of these automakers would survive for more than a few years, though many legends were born during this automotive primordial soup era – companies like Lotus, Marcos, and TVR.

TVR had started out in 1946 in Blackpool, England. The company was founded by Trevor Wilkinson, he initially called it Trevcar Motors however it was soon changed to the name it still carries today – TVR.

The early years were defined by Wilkinson working largely alone, repairing cars and doing other automotive work, but this all changed in 1949 when he developed and built his own chassis alongside his company’s first employee – Jack Pickard.

Early successes encouraged the two men, and they developed a series of one-off road cars and racing cars. By 1958 they were ready of the big league – they developed the TVR Grantura as their first production automobile and put it on sale.

Weighing in at just 650 kilograms or 1,433 lbs, the TVR Grantura is both lightweight and aerodynamic – making it a formidable race car in its displacement class.

The TVR Grantura

The TVR Grantura was developed using the many lessons that had been learned in the early years of the company. The Grantura was intended to be a road-legal sports car that would double as a highly effective racing car – with a few modifications here and there.

All generations of the Grantura had a tubular steel backbone chassis – this would be a design feature used by TVR in one way or another for decades and it’s a concept that works exceedingly well.

This chassis was clothed in a fiberglass body that was quick to make and very lightweight, and many other parts including the drivetrain, brakes, and suspension were sourced from other mass-produce British cars.

The Mark I Grantura was a relatively simple affair, with a choice of engines from 1.1, 1.2, and 1.6 liters. It had drum brakes from the Austin-Healey 100 and VW Beetle-based front and rear suspension.

This is the BMC 1,588cc inline four that was also used in the MGA. This engine has been rebuilt by Hurley, and it retains its twin SU carburetors.

The Mark II Grantura was a more refined car and a sign of things to come, it now came with the 1.6 liter MGA engine as standard and it had a longer, stronger chassis as well as independent suspension on all four corners.

The TVR Grantura became a common sight on race tracks around Britain, frequently winning and/or landing in the podium places. The cars were also raced on the Continent and across the Atlantic in North America against other cars in their engine class – like the Porsche 356, the MGA, various Triumphs and Lotuses, and more exotic cars like the Alfa Romeo Giulia TZ.

Thanks to the low weight of the Mark II, just 650 kilograms or 1,433 lbs, the car would frequently beat production cars (like the MGA) that its engine was sourced from.

The Grantura would continue to be modified and refined over the course of its production run, right up until it was replaced by the somewhat similar TVR Vixen in 1967.

The original seats, central tunnel upholstery, door cards, and roof lining have all been kept in place, giving the car the look and feel of a proper ’60s racer.

The TVR Grantura Mark II Shown Here

The car you see here is the slightly more refined Mark II version of the Grantura, with the stronger, longer chassis, the more powerful 1.6 liter MGA engine, and independent suspension all round.

Originally registered new in England in April 1961, this TVR was fitted with the popular 1588cc BMC engine also used in the MGA. It was kept for 28 years by its first owner, it was then sold to a collector who took the car to numerous events and won several prizes with it.

Over four years between 2006 and 2010, the car was fully restored down to the bare chassis, it retained the original upholstery and interior, and a new 5-speed gearbox was fitted – though the original will also be delivered with the car.

Specialists Hurley rebuilt the 1.6 liter engine, including the twin SU carburetors and the rare HRG Engineering rocker cover. The car is now registered in France and it comes with a lengthy history folder, including invoices, photos, letters, technical documentation, period articles and even a period user manual.

If you’d like to read more or register to bid you can click here to visit the listing. It’s due to cross across the auction block on the 18th of March with a price guide of $22,800 – $34,200 USD.

Images courtesy of Artcurial

The post An Affordable Le Mans Classic Racer: The 1960s TVR Grantura appeared first on Silodrome.

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A Rare Supercar Killer: The Brooke Cosworth Double R Supercharged 400

This is the only alloy-bodied Brooke Cosworth Double R Supercharged 400 in the world. While that name may be a bit of a mouthful it does tell you something important – this featherweight two-seater is powered by a supercharged Cosworth engine producing 400 bhp.

400 bhp is vastly more than most cars produce, even most modern sports cars, and it’s within sight of the 471 bhp produced by the Ferrari F40 and the 444 bhp produced by the Porsche 959. The key difference being weight – the Brooke Cosworth weighs in at just 510 kgs (1,124 lbs).

Fast Facts – The Brooke Cosworth Double R

• The Brooke Cosworth Double R Supercharged 400 was introduced in Britain in 2006 and it quickly received glowing reviews from British motoring media.
• The car is an all-new design based on the earlier Brooke Kensington ME190 designed to compete with the Caterham CSR 260. Unlike the Caterham, the Brooke has a mid-engined layout.
• Just 15 examples of the Double R were ever made and the car you see here is the only one with a full alloy body – a £15,000 ($20,300 USD) factory option.
• The non-supercharged version of the Brooke Cosworth Double R has a tubular steel spaceframe chassis, a longitudinally mid-mounted 2.3 liter 260 bhp Cosworth inline four-cylinder engine, a 5-speed gearbox, independent suspension and disc brakes at all four corners, and either a fiberglass or alloy body.

Brooke Cars And The Cosworth Double R

When the Brooke Cosworth Double R and its sibling, the Brooke Cosworth Double R Supercharged 400 were released in 2006 it’s likely that the folks over at Caterham sat up and took notice.

The cockpit is spartan to say the least, with seating for two a shared footwell, a removable steering wheel, and a right-side shifter.

Based on the design of the earlier Brooke Kensington ME190, the Brooke Cosworth Double R was a re-engineered vehicle with no interchangeable parts with its forebear. It has a lot in common with the cars from Caterham with the exception of one thing – the engine is behind the driver rather than in front of them.

Brooke Kensington was originally founded in the mid-1990s as a kit car company, one of many in the UK, producing their unusual two-seater that seemed to take equal parts of influence from the Light Car Company’s Rocket and the Caterham 7.

Brooke Cosworth Double R Specifications

The company was taken over in the early 2000s by James Booker, with James Rose (ex-MG Rover) as the primary technical development engineer. They developed two key versions of the car, the non-supercharged Brooke Cosworth Double R, and the supercharged variant with 400 bhp, the appropriately named Brooke Cosworth Double R Supercharged 400.

Both cars are powered by the 2.3 liter 260 bhp Cosworth inline four-cylinder engine, essentially the same engine used by the Caterham CSR 260. Each of these engines was built by hand by Cosworth in the same facility where they were making the engines for the Williams Formula 1 Team.

This is the supercharged version of the 2.3 liter Ford Cosworth inline four-cylinder engine, it produces 400 bhp despite its diminutive size and it was built by the same people who were building Formula 1 engines for Williams.

The naturally aspirated version of this engine produced 260 bhp, with the supercharged version making 400 bhp.

In a car that weighs just 510 kgs (1,124 lbs) the 260 bhp engine option was already more than ample, but with the 400 bhp engine the Brooke became a legitimate supercar killer –  accelerating from 0 – 60 mph in ~2.9 seconds, and on to 100 mph in 6.5 seconds.

Though obviously the top speed of your average supercar will be higher, this only has a limited impact on a race track where the acceleration, braking, and cornering abilities of the Brooke would potentially give it an edge – depending on the specific track of course.

Thanks to its stiff, lightweight tubular steel spaceframe chassis, its lightweight fiberglass (or alloy) body, race-tuned independent suspension on all four corners and four wheel disc brakes, the Brooke Cosworth Double R was one of the quickest cars in its £31,995 ($43,350 USD) price range.

The End Of The Road

At some point between 2006 and 2014 Brooke Cars ceased trading, information about it is scarce but the cars the company built during their brief few years of operation are now much sought after by those looking for an interesting alternative to a Caterham 7.

Operating a low-volume car company is a difficult business, the majority that try it tend to fail, however thanks to those that try we have ended up with a number of fascinating cars throughout history – vehicles like the Tucker 48, Bricklin SV-1, DeLorean DMC-12, Vector W8, and the car you see here, the Brooke Cosworth Double R.

Just 1 of the 15 cars that were built had the full alloy body option, it costs an extra £15,000 ($20,300 USD).

The Brooke Cosworth Double R Supercharged 400 Shown Here

This is actually the second time we’ve featured this car on Silodrome, it was last sold in 2021 and since this time it’s accumulated very little mileage.

This car is one of just 15 that were built and it’s the only one with a full aluminum alloy body, originally a £15,000 ($20,300 USD) factory option.

The first owner of this car kept it in an air tight storage bubble for the first 12 years of its life. The second owner drove it a little more frequently but the mileage stayed very low, just 1,369 at the time of cataloguing.

In January of 2022 this Brooke was given a servicing by Bell Sport and Classic, and it’s now ready for its new owner – whether they should wish to drive it or store it as an investment.

If you’d like to read more about this car or register to bid you can click here to visit the listing on Silverstone Auctions.

Images courtesy of Silverstone Auctions

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