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post #1 of (permalink) Old 09-29-2007, 07:22 PM Thread Starter
El Calor
 
Join Date: Sep 2007
Posts: 61
ZR1 History and Specs


ZR-1 (aka King of the Hill)

In 1986, the Corvette team approached Lotus, then a GM subsidiary, with the idea of developing an ultra-high performance vehicle based on the C4 generation Corvette. With input from GM, Lotus designed a new engine to fit in place of the L98 V8 that was powering the standard C4. The result was what GM dubbed the LT5, an aluminum-block V8 with the same bore centers as the L98, but with four overhead camshafts and 32 valves. Lotus also designed a unique air management system for the engine to provide a wider power band by shutting off 8 of the 16 intake runners and fuel injectors when the engine was at part-throttle, while still giving the ZR-1 a stellar 375 hp when at wide open throttle.

In addition to the engine, Lotus aided the development of the ZR-1's standard "FX3" active suspension system, helping to ensure that the vehicle had real capability on the race track.

Since the engine required precise hand assembly, and because neither the Corvette plant in Bowling Green, Kentucky nor any of GM's normal engine production facilities could handle the workload, Mercury Marine corporation of Stillwater, Oklahoma was contracted to assemble the engines. Completed LT5's were shipped to the Corvette factory in Bowling Green, where the ZR-1s were being assembled.

The vehicle went on sale in 1990 and was distinguishable from other Corvette coupes by its wider tail section, 11 inch wide rear wheels, new convex rear fascia with four square shaped taillights, and a third brake light mounted at the top of the rear glass.

The ZR-1 displayed stunning ability both in terms of acceleration and handling capabilities, but it carried an astonishingly high price tag: MSRP for the ZR-1 in 1990 was $58,995 (almost twice the cost of the base model), and ballooned to $66,278 by 1995; it was reported that some dealers successfully marked units as high as $100,000. Even at its base MSRP, the ZR-1 was competing in the same price bracket as cars like Porsche's 964-generation 911, making it a hard sell for Chevrolet dealers.

In 1991, all Corvettes received updates to body work, interior, and wheels. The convex rear fascia that set the 1990 ZR-1 apart from the base model was now included on L98 Corvettes, making the styling of the expensive ZR-1 even closer to that of the base cars. The most obvious difference remaining between the base and ZR-1 models besides the wider rear wheels was the location of the CHMSL (center high mounted stop lamp), which was integrated into the new rear fascia used on the base model, but remained at the top of the rear-hatch on the ZR-1's.

Further changes were made in 1992: ZR-1 badges were displayed on both front fenders and traction control was added as a standard feature. In 1993, Lotus redesigned the cylinder heads and valvetrain of the LT5, resulting in a horsepower increase from 375 to 405. In addition, a new exhaust gas recirculation system improved emissions control. Production of the ZR-1 ended in 1995, after 6,939 cars had been built.

Although the ZR1 was extremely quick (0-60 mph in 4.6 seconds, and onto 180+ mph), the huge performance of the LT5 engine was matched by its robustness. As evidence of this, a stock ZR1 set a number of international and world records at a test track in Fort Stockton, Texas on March 1, 1990, which was verified by the FIA (Fédération Internationale de l'Automobile), including:

7 New International Records:

* 100 Miles @ 175.600 mph;
* 500 Miles @ 175.503 mph;
* 1000 Miles @ 174.428 mph;
* 5000 km @ 175.710 mph;
* 5000 Miles @ 173.791 mph;
* 12 Hours Endurance @ 175.523 mph;
* 24 Hours Endurance @ 175.885 mph for 4,221.256 Miles

3 WORLD RECORDS - IRRESPECTIVE of CATEGORY or CLASS:

* 5000 km @ 175.710 mph;
* 5000 Miles @ 173.791 mph;
* 4,221.256 Miles @ 175.885 mph

These records remain unbeaten today by any subsequent Corvette, including both the C5 and C6 Z06s.
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