200tdi rev counter

I have a 52mm rev counter of a BMW boxer twin on the back of it it has 4 wires 1 to feed for the bulb ,1 with a+ ,1 with a-, and 1 with a Z now asuming i have a W terminal on the back of my Alt. can i use this counter? if so anyone knows witch wire i use for it .I am sure the'r some bright sparks amongs you guys .

i'd connect z to w and expect the counter to move when you rev the engine, but remember that boxer engine is probably designed to rev to around 7000-9000 rpm so you will only see movement across part of the scale

Yeah well as long as it reads up to 3500, and 800 at ticover i guess it will be OK .thanks mate ill give it a go tomorow.