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Written by Dan Carney
In developing the last, highest-performance version of the current C7-generation Chevrolet Corvette, airflow management was the primary overriding concern for the car"s engineering team. That"s because the 755-hp (563 kW), 715-lb ft (969 N m) supercharged 6.2-L LT5 V8 produces even more heat and speed than the 650 hp (485-kW) LT4 in the Z06. GM engineers note that small-block struggled to shed heat when driven hard in warm temperatures, and the ZR1"s anticipated top speed of more than 210 mph demands careful management of the airflow to ensure stability at such elevated speeds. "Managing the airflow around the car was a huge emphasis," explained Executive Chief Engineer Tadge Juechter. "This is the first time we"ve spent this much time with a moving ground plane wind tunnel." Of course, computational fluid dynamics was also critical in shaping the ZR1"s body shape, pointed out Exterior Design Director Tom Peters. "The CFD work is so important for us to understand where the hot spots are, so we can get right to it." The LT5 engine producing that heat employs a 2.65-L Eaton twin-scroll supercharger inhaling though a 95mm Hitachi throttle body commissioned especially for this car. It features GM"s first use of a dual fuel injection system, with direct injection as the primary system and high-flow port injection providing fuel at high loads. The crankshaft includes a wider key slot to handle the extra power and the oil system is dry sump to withstand high cornering forces. The engine exhales through a two-stage muffler system with both active and passive elements to vary the sound level of what Chevrolet is calling "the loudest and most aggressive-sounding production Corvette in history." This employs new technology for which "we"ve applied for and expect to get some patents," said Juechter. Transmissions are either a seven-speed manual transmission or an 8-speed automatic. GM"s new 10-speed automatic transmission co-developed with Ford won"t fit in the Corvette"s frame, according to Juechter. The available ZTK Performance Package includes Beijing West Industries (BWI) MagneRide adjustable dampers, Brembo carbon ceramic brakes and Michelin Pilot Sport Cup 2 tires. The car"s entire front bodywork is unique, providing huge openings for the ZR1"s 13 heat exchangers (four more than the Z06) and a hood cutout that lets the supercharger"s cover protrude through to the outside. This set-up is not pedestrian protection-compliant, so the ZR1 will not be sold in Europe. The frame structure beneath the hood is also changed to accommodate outboard heat exchangers added on the left and right sides in addition to the existing central radiators. The car is dressed in book-matched carbon fiber elements from deBotech, Inc. The major parts are the front underwing, which replaces the conventional flat splitter with an inverted wing for maximum downforce. The inverted wing is needed to balance the downforce of the mammoth rear wing, which applies its 950 lb (431 kg) of downforce directly to the ZR1"s frame using mounts that pass through the rear bodywork. Otherwise, the body panels would deflect at speed, causing potentially dangerous changes to the wing angle, Juechter said. That wing includes 5 degrees of adjustability for precise track tuning.
Date written: 03-Dec-2017 09:27 EST
More of this article on the SAE International Website
ID: 10172
In developing the last, highest-performance version of the current C7-generation Chevrolet Corvette, airflow management was the primary overriding concern for the car"s engineering team. That"s because the 755-hp (563 kW), 715-lb ft (969 N m) supercharged 6.2-L LT5 V8 produces even more heat and speed than the 650 hp (485-kW) LT4 in the Z06. GM engineers note that small-block struggled to shed heat when driven hard in warm temperatures, and the ZR1"s anticipated top speed of more than 210 mph demands careful management of the airflow to ensure stability at such elevated speeds. "Managing the airflow around the car was a huge emphasis," explained Executive Chief Engineer Tadge Juechter. "This is the first time we"ve spent this much time with a moving ground plane wind tunnel." Of course, computational fluid dynamics was also critical in shaping the ZR1"s body shape, pointed out Exterior Design Director Tom Peters. "The CFD work is so important for us to understand where the hot spots are, so we can get right to it." The LT5 engine producing that heat employs a 2.65-L Eaton twin-scroll supercharger inhaling though a 95mm Hitachi throttle body commissioned especially for this car. It features GM"s first use of a dual fuel injection system, with direct injection as the primary system and high-flow port injection providing fuel at high loads. The crankshaft includes a wider key slot to handle the extra power and the oil system is dry sump to withstand high cornering forces. The engine exhales through a two-stage muffler system with both active and passive elements to vary the sound level of what Chevrolet is calling "the loudest and most aggressive-sounding production Corvette in history." This employs new technology for which "we"ve applied for and expect to get some patents," said Juechter. Transmissions are either a seven-speed manual transmission or an 8-speed automatic. GM"s new 10-speed automatic transmission co-developed with Ford won"t fit in the Corvette"s frame, according to Juechter. The available ZTK Performance Package includes Beijing West Industries (BWI) MagneRide adjustable dampers, Brembo carbon ceramic brakes and Michelin Pilot Sport Cup 2 tires. The car"s entire front bodywork is unique, providing huge openings for the ZR1"s 13 heat exchangers (four more than the Z06) and a hood cutout that lets the supercharger"s cover protrude through to the outside. This set-up is not pedestrian protection-compliant, so the ZR1 will not be sold in Europe. The frame structure beneath the hood is also changed to accommodate outboard heat exchangers added on the left and right sides in addition to the existing central radiators. The car is dressed in book-matched carbon fiber elements from deBotech, Inc. The major parts are the front underwing, which replaces the conventional flat splitter with an inverted wing for maximum downforce. The inverted wing is needed to balance the downforce of the mammoth rear wing, which applies its 950 lb (431 kg) of downforce directly to the ZR1"s frame using mounts that pass through the rear bodywork. Otherwise, the body panels would deflect at speed, causing potentially dangerous changes to the wing angle, Juechter said. That wing includes 5 degrees of adjustability for precise track tuning.
Date written: 03-Dec-2017 09:27 EST
More of this article on the SAE International Website
ID: 10172
