VHP new “ACCELERATED LIFT” rocker arm geometry has opened the door to a new area of valve train development and cam lobe design that is producing impressive results. The “ACCELERATED LIFT” geometry is not magic; it is simply a new design of the rocker arm body that locates the pushrod seat low in the body with respect to the center of rotation about the shaft. Because the pushrod seat area travels in an arc as the lifter/pushrod moves upward during the lift event, the pushrod seat moves slightly away from the center of rotation around the shaft. This movement of the seat through its operating arc causes the effective rocker arm ratio to decrease. The end effect is this: a 1.6 ratio “ACCELERATED LIFT” rocker arm actually starts opening the valve at a ratio of 1.7. As the valve opens, the rocker ratio decreases to the 1.6 advertised ratio (this occurs at about .250” - .300” valve lift) and then maintains the 1.6 ratio through the rest of the lift cycle until it starts back on the seat. It goes back on the seat at a 1.7 ratio. This new geometry provides increased airflow earlier in the lift cycle and maintains it longer into the closing event. More flow equals more power! There are additional benefits. The “ACCELERATED LIFT” design applied to computer managed engines means that short seat-to-seat timing can be maintained to provide high vacuum at idle and low speed, but duration at .100”, .200” etc. is equal to camshafts having .050 durations 8 to 10 degrees bigger. This means great power increases and ease of tuning the engine management system. “ACCELERATED LIFT” geometry is the future for pushrod engines and VHP has it for you today!
VHP has also designed new camshaft lobes to maximize the advantage of these rockers. The new “ACCELERATED LIFT” lobes are being used in all of our new racing profiles, as well as our new LS1 family of cams for GM cars and trucks. Performance enthusiasts have known for over 25 years that the best lobe design to maximize “area under the lift curve” is the “inverted flank roller lobe:” However, the “inverted flank design” creates several manufacturing headaches which cause the price of these designs to be quite high. VHP'S new “ACCELERATED LIFT” Rocker body design and new complementary “ACCELERATED LIFT” cam lobe designs have produced a valve lift profile that exceeds the power potential of the “inverted flank” designs. These new profiles are available on all of the latest LS1 cams, including the “Truck Power” cams and many of the new racing cams. Most of our future pushrod camshaft designs will incorporate the “ACCELERATED LIFT” technology.