What's a ZR1 ?

 In 1990 the 'King of the Hill' was on sale for the first time. In the mid 1980s GM approached Lotus with the idea of developing the world's fastest production car. From the hard work and commitment that followed came the LT5 engine.

The LT5 was an all aluminium V8 block with the same bore as the standard (L98) 350ci (5.7l) engine. Unlike the L98 the LT5 block had four overhead camshafts, 32 valves and 16 injectors.

The LT5's were built by Mercury Marine at Stillwater, Oklahoma and were then transported and fitted into the ZR1's at the Bowling Green assembly plant. After GM made the decision not to build the LT5 in-house, Mercury Marine were chosen to assemble the all aluminium LT5 due to their experience with aluminium marine engines.

The engine produced 375 BHP in earlier models and 405 BHP in later models.  The ZR1 featured a unique 'valet key'. The valet key can be found on the centre console and when switched to 'Normal Power',  the engine would run with around 250 BHP. But when switched to 'Full Power' mode the full power of the LT5 is there to be unleashed.

The ZR1 was sold as an option over the standard Corvette, then priced at around $32,000. Opting for the ZR1 would nearly double that tag of $32k. There are rumours of people paying $100,000 for a ZR1.

You can tell a ZR1 apart from a standard Corvette by its rear end. Its rear wheels were widened to 11" on which huge 315 low profile tyres were mounted. To accommodate those wider wheels, the rear end of the car was widened by around 3". With a ZR1 and a standard C4 parked side-by-side, the difference in width is obvious from the doors back and it gives the car a more aggressive presence. The rear of the car was also different. Instead of the concave rear with the traditional twin round rear lights either side, the ZR1 had a wider convex rear with squared off rear lights  - although later C4's moved on to a convex rear section similar to the ZR1.

The ZR1 had up-rated brakes and the 3 way adjustable FX3 suspension package. The ZR1 was only available with a 6-speed manual gear box. There was no auto version. Although there was a convertible car built (named the DR1) it never went into production so the ZR1 was only available as a coupe.

Performance was outstanding, even by today's standards. The car was tested and developed by GM back-to-back with the likes of the Ferrari Testarossa and other exotica and was developed to be a better performer.

With a top speed of 180mph+, 0-60 in the mid 4 seconds, a standing quarter in the high 12 seconds and 0.94g on the skid pad, the car was definitely competitive. Add to that an average mpg of 20 miles to a gallon (US) and an engine that had to pass GM's reliability tests. What other car of this performance could offer all this back in 1990 ?

In all, a total of 6,939 ZR1's were built between 1990 and 1995.

If you own a ZR1 then the ZR1.NET is a must. Check it out now

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