XMS4 - INTERFERENCE & NOISE APPLICATION

Perfect Power Application Notes.

 

Application Note - AN 11

This is a nasty subject! If confuses the best of us, and places havoc with our XMS4 setup and performance.

 

Who Generates Noise and Interference?

  • Anything that sparks
  • Anything that uses high current

 

Precautions against interference

  • Shield pickup wires, but do not connect the shield on both ends
  • Do not run the ignition wires parallel to sensor wires
  • Connect the electronics ground (black) to the NEG battery terminal
  • Connect the POWER GROUND (green/yellow) to the chassis
  • Do not run ANYTHING parallel to the coil wires, or plug leads.

 

Noise Filter

The XMS4 has filters built-in. These filters are against transients, noise and spikes. However, these filters have a "CUT OFF" limit of approx. 10 KHz, which is required for a 60 teeth pickup at 10 000 RPM. This frequency limit may be too high in your application, and it can be changed with external components, which is shown later.

 

 

I have done everything possible, but I still get noise interference

Yes, I had some of these problems!

If you are running a 60 teeth pickup, you are in trouble.

If you are running a normal pickup (one tooth per firing) then there is a solution :

 

Add an external input filter as follows :

 

XMS4 Stand Alone Unit - Add an External Input Filter

 

 

If the signal from the pickup is too big, then the 2K2 (or 1K) reduces the voltage and increases the RPM limit.

The component values are not very critical, until the engine stops at high RPM. These filter components must be installed as CLOSE as possible to the XMS4.