Howdodeydodat... Ratio rockers merely amplify the distance the valves open. For a 0.5 inch lift cam a 1.25 ratio rocker raises the motion of the valve by 25% or makes the valve open to 0.625 inches instead of 0.5. This may allow more of a fuel charge to enter the cylinder. Note the "may". It has the same effect as a "hi lift cam" The degree specifications (duration) for the cam remain the same but the lift is magnified by 1.25, 1.3 or whatever the ratio is for the particular rocker. EG still opens at XX deg BTDC and closes at YY deg ATDC. Overlap remains the same. The effect is to have the intake valve open faster and close faster with the obvious increased accelerations of the valve gear. This may put a bit more wear on the components. Note the "may". Coupled with intake/exhaust system smoothing and compensation in the fuel metering, very significant power gains can be achieved. Efficiency may or may not increase with the modifications. cheers, pensioner |
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