The valvetrain also received stiffer valvesprings to reduce the potential of valve float at high rpm. The pistons received larger valve reliefs to accommodate the increase in valve diameter. The VCT system was also revised to limit camshaft movement (from 50 degrees of crankshaft rotation to 25 degrees of crankshaft rotation.) This was done to improve cold-start emissions with the Gen 2's larger camshafts. The Gen 2 cylinder heads features larger intake and exhaust valves (37mm intake/31mm exhaust for Gen 1, 37.3mm intake/31.8mm exhaust in Gen 2) and increased lobe lift on both the intake and exhaust camshafts (12mm int./exh. The changes for the second-generation Coyote (2015-2017) were widely focused on airflow and high-rpm operation. The engine received some updates and upgrades to coincide with the all-new S550 chassis. Add boost to the mix, and the Coyote is a dream come true for engine builders and tuners! This change in LSA directly relates to cylinder pressure, which is directly related to horsepower and torque production. With Ford's Ti-VCT, you get the best of both, as the LSA changes in step with the speed of engine (controlled by the engine strategy). If the LSA was narrow, the power curve was shifted to a higher rpm there was always a sacrifice. If the cams were installed with a wide LSA, your power curve was shifted to a lower rpm. In the past, this was a fixed aspect of the camshafts. Why is this important? Because it allows the amount of time the intake and exhaust valves are simultaneously open in the combustion chamber to be adjusted dynamically. The most significant part of this system is that the intake and exhaust camshafts can move independently of each other, making the lobe separation angle (LSA) dynamic. This also allows for increased fuel economy with lower emissions. Both the intake and exhaust camshafts have a swing of 50 degrees (crankshaft rotation), allowing the cams to advance and retard for dynamic horsepower and torque production depending on how the car is being driven.
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