Porsche 911 GT3 Owner's Manual page 146

SET
Basic setting on on-board computer
Switching on selection field "D"
f Push operating lever forward.
Changing the basic setting of the on-board
computer
f Select "SET" with the operating lever.
f Push operating lever forward.
f Select the desired function with the operating
lever:
Reset
– Reset all,
Reset average consumption,
Reset average speed,
Reset trip counter
Units
– Speedometer: km - km/h, miles - mph
– Consumption:
l/100 km, mls/gal (USA), mpg (UK), km/l
– Temperature: °Celsius, °Fahrenheit
– Tire pressure: bar, psi
Instruments, On-Board Computer
145