This isnt eagle related but for my Mitsubishi. I have a bad alternator whine in my speakers. I have a aftermarket head unit. Im trying to fix this annoyance. Im thinking of grounding the unit to the frame also try those noise reducers. Anybody got any background in this
Hook up a Radio Frequency Interference Capacitor.
Ignition systems produce sparks (and therefore radio frequency interference) at the coil where battery voltage is converted into high voltage that can jump across the gap in a spark plug, at the distributor where the high voltage is channeled to the proper plug, and at the spark plug itself where the spark ignites the controlled burning of the gasoline/air fuel mixture. Diesel engines compress fuel to ignite it in a process that produces negligible "noise."
The noise generated by a gasoline engine ignition system comes primarily from the high-voltage side of the circuit.
It's very effective in suppressing engine "noise," and it doesn't affect engine performance.