The 2014 Corvette Stingray coupe is on sale this fall, with a convertible following by the end of the year.
The 2014 Corvette Stingray’s LT1 6.2-liter V8 engine is SAE-certified at 455 horsepower (339 kW) and 460 lb.-ft. (624 Nm) with the standard exhaust system. Previously GM touted horsepower beginning at 450, then 460, which was obtained with an optional exhaust system at 6000 rpm and 465 lb.-ft. of torque (630 Nm) at 4600 rpm.
The LT1 alone in the performance engine world remains a push rod design. Nonetheless, these are the highest standard power ratings ever for Corvette, with still un-certified fuel efficiency levels unofficially pegged at about 26 mpg on the highway. Chevrolet estimates Corvette will run from zero-to-60 mph in less than four seconds. Given the electronic controls over-ruling the driver, GM’s long-standing small-block expertise and a culture of integrity at Corvette, I have no doubt that the number is solid.
The first small block V8 debuted in the Corvette in 1955. It displaced 4.3-liters (265 cubic inches) and was rated at 195 horsepower, drawing air and fuel through a four-barrel carburetor.
At 74 horsepower per liter, the LT1 has greater power density than the C6 Corvette’s LS3 6.2-liter engine as well as the C6 Z06’ 7-liter LS7. It also produces comparable torque to the LS7 – up to 4,700 rpm – and its peak torque is within 5 lb.-ft. of the 7-liter engine. The torque is appear at low engine speed and sustained across the rpm band, with 316 lb.-ft. available off idle at 1000 rpm and 90% of peak torque available from 3000 rpm to 5500 rpm, which on paper makes for a responsive sports car.
The latest Corvette LT1 engine, the first of the so-called Gen 5 family of small-block engines, combines several advanced technologies, including direct injection for the first time, cylinder fuel shut off and continuously variable valve timing to support an advanced combustion system. The new LT1 is the third engine in the Corvette’s history to be so-branded, with previous versions introduced in 1970 (Gen 1) and 1992 (Gen 2).
Virtually all of the benefits arise from direct injection, which allows a high compression ratio.
The LT1 cylinder head has smaller combustion chambers designed to work with the volume and the new shape of the pistons’ heads. The smaller chamber size and sculpted pistons produce an 11.5:1 compression ratio, while the cylinder head has large, straight and rectangular intake ports with a slight twist to enhance mixture motion. There is a reversal of the current intake and exhaust valve positions when compared to the previous engine design. The spark plug angle and depth are revised to protrude farther into the chamber, placing the electrode closer to the center of the combustion to support “optimal” combustion.
GM President North America Mark Reuss unveils the 2014 Stingray on Sunday 13 January in Detroit. The new Corvette is the most powerful and expensive standard model ever. C7 will accelerate from zero-to-60 mph in less than four seconds. It’s also claimed to be the most fuel-efficient Corvette, exceeding the 26 mpg of the current model.
Chevrolet said that more than 10 million hours of computational analysis conducted during the engine program, included 6 million hours dedicated to the advanced combustion system. Virtually all of the claimed benefits arise from direct injection. It allows exact control of the mixture motion and fuel injection spray pattern. Direct injection also keeps the combustion chamber cooler, which allows for a higher compression ratio. Emissions are also reduced, particularly cold-start hydrocarbon emissions, which are cut by about 25%.
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