Using these inputs, the ECU is programmed to switch from the low lift to the high
lift cam lobes when certain conditions are met.
Not exact matches
The previous LS versions have extensive aftermarket support where builders talk head airflow statistics, rod ratios (connecting rod divided by stroke),
cam durations,
lift and
lobe separation and inductions schemes.
If you grind this area down, the
lift from this portion to the top of the
cam lobe becomes a larger distance, and thus you have more
lift and more potential air flow going into the cylinder.
Theoretically the worn
cam lobe can be reground to regain the
lift.
When in VTEC, since the «normal»
cam lobe has the same timing and
lift as the intake
cam lobes of the SOHC non-VTEC engines, both engines have identical performance in the upper powerband assuming everything else is the same.
Also, you will want to use a
cam specific lube on the camshaft where the
lobes intercept ride on the
lifters (or whatever they are called... the caps on top of the valves which the
lobes ride on).
The
cam lobe profile selected for engine speeds below 3000 rpm has a duration of 214 degrees and
lifts the valves 5.5 mm.
For high - speed driving, CPS switches to a
cam lobe with a duration of 250 degrees and valve -
lift of 10.5 mm, allowing greater air flow into the engine for high power.
When the ejector pin is retracted, there is nothing to hold the
cam unit in this new position any more, so it will glide back to its original position to resume valve
lift via the smaller
cam lobe.
As a result, both intake valves follow a central high -
lift, longer - duration
cam lobe.
In order to achieve the optimum volumetric efficiency in the lower portion of the engine's operating range, rocker arms are programmed to follow
cam lobes that provide low
lift and reduced duration (shorter time open with less valve
lift).
As the engine load changes, electromagnetic actuators allow a movable shaft containing different
cam lobes to shift imperceptibly between high -
lift and low -
lift profiles.