Read off your mph at any rpm in any gear. Enter transmission and rear tyre data in the yellow boxes. Tyre diameter is automatically calculated from tyre profile info e.g. 195/55 x 15 = 24.44 inch tyre diameter.
This chart is particularly useful when used in conjunction with an engine’s power and torque data – showing what the rpm drop is in each gear when shifted at a specific engine rpm. For example, the default figures in the chart are for a stock ratio transmission as fitted to a Type 1, 1303S (3.88 ring and pinion).
Shifting at 5000rpm from 3rd gear into 4th (76mph), sees engine speed drop by almost 1500rpm, to a little over 3500rpm. If your dyno data shows the engine is making good torque after the gearshift and subsequent drop in rpm, acceleration in 4th gear will be strong. For maximum acceleration, as required in a drag race application, best track performance is found by keeping the engine between peak torque and a little after peak power in each gear.