Lets talk tachs Options

[Ductech]

I just finished up my ej22 subaru swap. after drag racing a rx7 in the boonies and self destructing my shifter, i have stopped to take a look at all the little stuffs. now my tach is a little bouncy compared to a nice new digital being fed by an obd2 car computer. As the wiring i used was the original tach signal wire, im wondering if a little bit of noise is most likely the issue or if the tachs on these were never that amazing in the first place. Thanks for the your help guys.

[Spoke]

Can you define bouncy? At steady RPM, is the tach steady or bouncing?

The 914 tach meter has almost no damping such that when revving the engine or shifting gears, the tach bounces or oscillates when going from one RPM level to the other.

Does yours bounce with constant RPM?

If it only bounces or oscillates when shifting or RPM changes, a 2200uF cap placed across the winding of the needle will steady the tach like a modern one.

Below are different responses to a step function (ie., RPM change). The stock 914 tach responds like the MU=6 curve.

MU=1 or lower is what you want for a response from the tach.