The basic function of Greddy Turbo Timer is to allow the engine to idle for a timed period with the ignition key removed. This allows the engine oil and turbo center cartridge to cool down to prevent internal turbo damage. The new Greddy Full Auto Timers pack tons of features in one economical, compact unit. In addition to two standard programmable count down present (P-1, P-2) our timer also has two Auto Timer modes, (A-L, A-H) which estimates the driving RPM according to the vehicles alternator signal and then recommends a count down time. And now there is a Stopwatch/Lap Time mode, and Attack mode. There is also a built in Voltmeter and Speedometer. Still standard are the optional Parking Brake and Speedo Safety hood-ups. 1990-1996 300ZX Harness Included($11.99 Value)