C8 Corvette ZR1 Will Reportedly Utilize Active Fuel Management
While enthusiasts typically don’t like AFM, the C8 Corvette ZR1 will likely employ it as a way to improve fuel economy.
Over the past few years, we’ve been treated to a bevy of rumors and spy sightings of the forthcoming C8 Corvette ZR1, which figures to immediately slot in the current lineup as the ultimate performance variant – at least until/unless the rumored Zora eventually takes that crown, that is. The C8 Corvette ZR1 will reportedly be powered by a twin-turbocharged version of the Z06’s 5.5-liter LT6 V8 dubbed the LT7. Now, we know yet another detail about this new powerplant – it will apparently utilize Active Fuel Management (AFM), according to GM Authority.
While the 6.2-liter LT2 V8 present in the C8 Stingray and E-Ray also employ AFM, this bit of news is quite notable because the Z06’s LT6 does not. While the LT7 is expected to be a bit different from the LT6 aside from the addition of the aforementioned turbochargers, it is based on that particular powerplant, so this comes as somewhat of a surprise, though there are some reasons why this might be the case.
AFM is GM’s proprietary variable displacement technology that was developed for one purpose in particular – to conserve fuel during the types of situations when boatloads of power aren’t needed, such as when the vehicle is idling or driving at low speeds. When that happens, the system essentially shuts down half of the cylinders in the engine, meaning that the Corvette’s V8 temporarily becomes a four-cylinder, at least until acceleration or other situations call for more power.
This tech improves fuel economy by around 6-8 percent, according to EPA estimates, and has been used in a variety of V6 and V8-powered GM vehicles for decades to this point, previously known as Displacement on Demand. It works by using a solenoid control valve assembly to turn off the intake and exhaust valves via pressurized oil that activates and deactivates the hydraulic roller lifters. When needed, the exhaust valve reopens to discharge old exhaust gas and allow in a new cycle.
While enthusiasts tend to lament such systems for their complexity and the potential annoyance of having half their cylinders deactivate when the car deems such a thing to be necessary, GM is likely utilizing AFM in the LT7 as a way to eek out a little more fuel economy from an engine that’s very unlikely to return solid numbers in that regard. After all, the Z06 only returns around 12 mpg in the city and 19 on the highway, so we can only imagine what a pair of turbos and some extra power will do to those figures.
Photos: CorvetteForum, Chevrolet
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