[WOB} re: interesting discovery

[Knute Ream <knute@xxxxxxxxx>]

Jimmy Ray <p1atinum@domain.elided> wrote:
[...]
>interestingly enough the static sounds coming from the AM of the radio
>is synchronized with my exhaust/rpm!! as i step on the gas, the
>engine/exhaust get louder and the static pitch gets higher, and as i
>let go of the gas, it gets lower.
[...]
>now, i have only b&b triflow exhaust on my 95 325i with no other
>engine mods, has this happened to others? or am i just finally
>discovering something that has been known for ages??
>
>and it shouldn't be something that i worry about right??
>
>sorry for the silly WOB
>
>jim

Nikola Tesla noticed this too...   (Electrical sparks result in radio
frequency emissions)

Depending on which history book you read, Nikola Tesla or Guglielmo Marconi
was the father of radio (I tend to believe it was Tesla, since his patents
predate Marconi's), and he built some truly bubba-class tesla coils in the
process.  The biggest of these monsters was at a lab in Colorado Springs
near the turn of the century.  Called the 'Magnifying Transmitter', it was
capable of generating some 300,000 watts of power, and (reportedly) could
produce a bolt of lightning 130 feet long. 

There are legends of his backyard radio experiments in New York, a
byproduct of which was nasty electric shocks to innocent bystanders 100's
of yards away hanging their laundry on wet clotheslines that acted like
antennas.  (Didn't do much for public support of radio at the time!)

Obligatory BMW content:  I'm sure Nikola Tesla would have driven a BMW if
he'd been able to obtain one...

The real answer to Jimmy's question is that this is perfectly normal,
caused by the firing of the sparkplugs, and the ability to pick it up on an
AM radio just indicates that the RF suppression techniques typically
applied to modern automobiles aren't perfect.

Regards,

- -Knute

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