Original H-O's
Overlap Flow Calculator

This calculator determines the net area flow during the intake & exhaust overlap phase of the Otto Cycle.

Select a head or enter your own data.

Head flow, CFM
Intake Exhaust E/I
.100:
.200:
.300:
.400:
.500:
.600:
.700:
.800:

Select an intake and exhaust camshaft lobe profile or enter your own.

Cam type
Intake cam lobe Exhaust cam lobe
Lobe lift: Valve Events In Valve Events
Rocker: IVOBTDC EVOBBDC
Valve lift: Adv In. Adv
Advertise: 050 Deg 050
Lift@adv: IVCABDC In. EVCATDC
0.050 dur: Adv Deg Adv
0.200 dur: 050 Deg 050
Centerline: Deg
Valve lash: Deg
Crank Exhaust Intake Overlap
Degree Valve lift |Area flow |Valve lift |Area flow |Net flow
45BTDC
40
35
30
25
20
15
10
5
TDC
5 ATDC
10
15
20
25
30
35
40
45
Net Net