Wasted Spark Tach/rev counter adapter

[Fordy]

So whilst the usual 2 diodes and 1 zener works.

Ive found high rpms on the guage don't match with those from a 36-1 wheel and for example megasquirt.

Found this updated Wasted Spark adapter design.
Tried it on mine and much smooth rev counter correctly reading.

The resistor acts as a pull down so basically the tacho input becomes a better cleaner high and low signal.

[Tutuur]

Cool stuff mate! Basically your sending a bit of the current back to ground to prevent the spikes from being too strong?

[Fordy]

Yes effectively,

The current dumps down the ground away from the Zener,
Rev counter still sees the voltage spike tho. Just much more clearly and also helps when hitting the standalone's rev limiter where it cuts the spark output.

Prolongs diode life aswell, it's all win win by adding the resistor

[Tutuur]

Such a simple solution

You ever managed to get any further with the Sagem 3000 mate?

[Fordy]

a little progress, had issues with my flashing tool, it had an update and a fellow tuner warned me that it killed an ecu on a 197 he was custom mapping. tool has been updated now tho.

ive got a few off the shelf maps in my hands aswell so need to convince the brother to give me his car for a week but he wants to use my R5 as a courtesy car

[Tutuur]

Your brother is smart

Off the shelf maps for the 197? Interesting

[Woznaldo]

I think this may help me as I was suffering the same issues on my wasted spark setup. The Tacho started to jump around when it got up to the 5000-5500 mark.