Radio noise
Thread Starter
Burning Brakes
Joined: Feb 1999
Posts: 1,157
Likes: 3
From: Encino CA
Radio noise
Since changing the plug wires on my 95 LT-1 from stock to MSD red (8.5mm), I notice a bit more radio noise at times. The first is the typical static clicking (sounds like cellophane) and is most noticeable on weak AM stations.
The second is much more subtle and is like a "whistling" that goes up and down in pitch when accelerating/decelerating. The odd thing is the whistling noise comes and goes. For example, I heard it today when first starting out (and listening to an FM station) but then it went away after a while.
I was wondering if there were some suppression filters that are built into the audio systems of our cars and, if so, are there stronger filters that can be installed?
Thanks,
Doug
The second is much more subtle and is like a "whistling" that goes up and down in pitch when accelerating/decelerating. The odd thing is the whistling noise comes and goes. For example, I heard it today when first starting out (and listening to an FM station) but then it went away after a while.
I was wondering if there were some suppression filters that are built into the audio systems of our cars and, if so, are there stronger filters that can be installed?
Thanks,
Doug
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
Factory and most replacement plug wires are resistance wire, about 5000 ohms per foot to greatly reduce spark noise on AM radios. If the MSD wires are copper, then your only solution if you want to keep the wires is to put them in a shielded grounded tunnel. The intermittent whistling you hear is alternator ripple caused by a poor battery cable connection. The battery filters out the alternator ripple, but when it becomes disconnected due to corrosion, the alternator ripple gets into your radio and your speaker amplifiers and you hear it. Remove your battery cables (neg first) and clean the cable lugs, bolts, and the battery terminals and replace the cables (neg last). This needs to be done periodically, like once or twice a year because small amounts of sulfuric acid attacks the cables and cause corrosion and a poor electrical connection. Battery cable connections should be like your lover, bright and tight! 
Thread Starter
Burning Brakes
Joined: Feb 1999
Posts: 1,157
Likes: 3
From: Encino CA
Thanks for the reply. Regarding the wires, MSD claims that "the construction of the MSD wires provides better EMI/RF shielding than OEM wires. The helical/spiral winding of the conductor is a self shielding design that cancels out noise". However, the dielectric grease is also supposed to be important to minimize "noise" and I suspect the shop that installed the wires did not bother to grease all the boots.
Regarding the whistle, the battery cable thing is great advice and something that I had never heard of or considered. I had never bothered cleaning the lugs before since they are a pita to get to but I will take a look. I guess this might also explain why the "whistle" comes and goes, sometimes within minutes.
Thanks,
Doug
Regarding the whistle, the battery cable thing is great advice and something that I had never heard of or considered. I had never bothered cleaning the lugs before since they are a pita to get to but I will take a look. I guess this might also explain why the "whistle" comes and goes, sometimes within minutes.
Thanks,
Doug
Team Owner
Joined: Mar 2001
Posts: 54,124
Likes: 30
From: Cincinnati, Oh USA
The silicone grease is for easy plug boot removal, it will do absolutely nothing for radio noise. A radio station strength has to be 100 times stronger than the ignition pulses (no bare wires are perfect in regards to radiating radio noise) in order to not hear them, so if you listen to weak out of town stations on AM, get used to some ignition noise. If it really bothers you, then install some metal grounded wire guides.
