Configure engine parameters and click Compute.

Cam Specification


Reference Lifts


LiftDescription
0.006"Advertised duration — longer, less accurate for physics
0.050"Industry standard — used for all calculations

Timing Events at 0.050"


  • IVO — Intake Valve Opens (° BTDC)
  • IVC — Intake Valve Closes (° ABDC) — primary driver of DCR and VE peak RPM
  • EVO — Exhaust Valve Opens (° BBDC)
  • EVC — Exhaust Valve Closes (° ATDC)

Derived Values


Overlap = IVO + EVC  (both before TDC)
LSA = (IntakeCL + ExhaustCL) / 2
IntakeCL = Duration/2 − IVO  [ATDC]
ExhaustCL = Duration/2 − EVC [BTDC]

Cam Advance Effect


Advancing the cam pulls IVC earlier → higher DCR, earlier intake pulse timing.

Each degree of advance ≈ 0.5% improvement in scavenging efficiency at overlap.