What does the positive or negative relate to when looking at the IVO settings? Is positive cam advance or cam retard?
Because this is set in crank angle I'm currently thinking that TDC is Zero in the IVO chart with crank degrees counting up from zero as the crank rotates. IF that is the case then negative values represent an advanced cam that opens before TDC and positive open after TDC. So, negative is cam advance, and positive is cam retard.
Am I looking at this correctly?
Stock 18 GT OP IVO chart and description from HPT for reference. In this case I'm assuming that the cam starts at advance and moves to retard as RPM goes up.
Stock 18 IVO.JPG
[ECM] 38158 - Optimum Power - Intake Valve Opening Angle vs. RPM: When in Optimum Power mode, this is the crank angle at which the Intake Valve will open based on Engine RPM.