Dear Nick Gammon.
I knew that arduino analog will unable to handle that level of voltage
Well ... actualy after some correction on that ''
with 132 tooth wheel, it can reach 154.985074626866 V at 4720 RPM
Using Voltage devider before entering Analog Pin
using R1=300 Ohm , and R2=10 Ohm
and
Vout = (R1/(R1+R2)Vin*
The Vout at 4720 RPM will be 4.99951853635051 Volt ... It is compatible with Analog PIN
The problem will : How much is the real max RPM of the engine
Sincerely
-bino-