VERY RARE 1991 CHEVROLET CORVETTE C4 ZR1, full original condition for its 32 years, only 56000 original km.
5.7-liter, 32-valve, 33 hp DOHC LT5 V8 engine, French "carte grise demi-tarif", 2 double overhead camshafts, 6-speed manual gearbox, for an incomparable sporty driving experience.
The interior is worthy of an aircraft cockpit, with an ergonomic dashboard and modern comfort features, including electrically adjustable leather sports seats in excellent condition, 2 T-TOPs, 1 panoramic glass as an option at the time + 1 black varnish.
With the close GM/LOTUS collaboration, the initial idea was to develop a Corvette at the pinnacle of technology and mechanical engineering. To this end, Lotus designed a new engine to replace the L98 V8 that powered the standard C4.
Lotus also designed a unique air management system for the engine to provide a wider power range by shutting off 8 of the 16 intake ducts and fuel injectors when the engine was at mid-range, while giving the ZR-1 380 hp (280 kW) at full throttle.
The result was what GM dubbed the LT5, an aluminum-block V8 with the same bore dimensions as the L98, but with four overhead camshafts and 32 valves is both smooth and torquey at low revs, but above all overpowering for its time.
In addition to the engine, Lotus helped GM design improved braking and steering systems for the ZR-1 (which, in prototype form, was called "King of the Hill").7) delivered as standard on the ZR-1. On the suspension side, DELCO/BILSTEIN's Selective Ride Control system was inspired by Citroën's work in this field. Offering three levels of damping (Touring, Sport and Performance), the system uses a computer to control a valve that varies the firmness of each shock absorber in 0.1 seconds, in both compression and rebound.
In early March 1990, the ZR-1 set a new land speed record over 24 hours and 8,000 km, exceeding an average speed of 282 km/h.
Another major innovation of the ZR-1 is its completely new three-phase fuel system. Each 16-valve cylinder head is fitted with 8 injectors and 4 dual-pipe manifolds of different diameters. On each cylinder, two intake valves of different diameters are activated independently by a specific camshaft. At low revs, below 3,500 rpm, the engine operates with only one of the three throttle body valves, the small intake manifolds and half the injectors sending the mixture to the small intake valves. This gives a maximum output of around 200 hp. The switch from 32 to 16 valves also reduces fuel consumption, a nod to the deactivation of the cylinders favoured by American V8s. After 3,500 revs, the big V8 changes morphology... The largest tubing diameter, all the injectors and all the valves are used! The small block then unleashes the full 375 horsepower at 6,000 rpm, with a rev limiter at 7,200 rpm, a feature rarely seen on an American production engine. By the way, it's almost as powerful as the TESTAROSSA of the time, except that the Italian was not catalyzed... and the 0 to 100 km/h time is only 5.6 compared with 4.8 sec for the Corvette.
With 530 Nm at 5,200 rpm, you have a good idea of the acceleration offered by this American engine. It's a serious mover, with 40 m.kg available at 1,500 rpm! Unlike the multi-valve engines of the time, there's no dip in torque at mid-range. This is where the Lotus system comes into its own! The V8 pushes in a linear fashion, retaining its typical smoothness at low revs, but also offering a never-before-seen rage at high revs!
To do this, simply turn the key to Normal mode. This principle has since been adopted by FORD and BUGATTI on the VEYRON.
On the gearbox front, the ZR-1 was one of the first production cars to be equipped with a six-speed manual gearbox. GETRAG and ZF are battling over ownership of this world first, but it doesn't matter. The ZF RPO LM9 transmission is the same as that fitted to the Lotus Omega and Toyota Supra mk4. Capable of handling a maximum torque of 576 Nm, it features a very long sixth gear, perfectly suited to .... the freeway. Another revolution was that no automatic gearbox was offered as an option! It's also worth noting that this rather special manual gearbox tends to put you into 4th gear instead of 2nd if you don't press down hard enough on the gas pedal! It's disconcerting to find yourself in 4th gear at 40 km/h. The CAGS (Computer Aide Gear Selection) system optimizes fuel consumption by taking four parameters into account: speed, water temperature, engine speed and throttle pressure. With a heavier foot, the ZR-1 catapults you to 100 km/h in barely more time than it took you to read this sentence - 4″8. The ZR-1's rear axle ratio is the same as the original (3.45), but acceleration and acceleration are particularly vigorous in the first five gears, and the top speed measured at 283 km/h chrono speaks volumes about the engine's allongevity. To top it all off, the engine growls, rumbles, roars, sings and even howls: wild! All with a typically American sound, despite its European origins. On the road, other cars seem to stand still when you accelerate... At the end of the journey, average fuel consumption is 11.4 liters, another pleasant surprise.
These were impressive figures for the time, and helped make the ZR1 one of the most attractive and fastest cars of its generation, already a collector's item.
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