Date: Fri, 29 Nov 2002 20:49:16 +0100 From: "Johan Beikes" <j.beikesnopsamdoo.nl> Subject: Re: c900 harmonic droning?
"Lance Morgan" <alancemornopsamo.com> wrote in message news:2a52f3e9.0211290413.70eff7ffnopsaming.google.com... > "Johan Beikes" <j.beikesnopsamdoo.nl> wrote in message news:<3de69281$0$10860$8fcfb86bnopsam.wanadoo.nl>... > > Lance, > > > > Another idea hit my mind: what about the exhaust system. Could it be too > > tightly mounted somewhere, so that noises of the exhaust are passed on to > > the chassis? > > Worth to look at, before thinking of more expensive fixes, i would think. > > > > Johan > > > > "Lance Morgan" <alancemornopsamo.com> wrote in message > > news:2a52f3e9.0211241647.193dd2ffnopsaming.google.com... > > > I recently purchased a 91 900S (briefly had a 86 900T years ago), and > > > am really enjoying it. > > > > > > I've noticed something I'd appreciate comments on: a harmonic type > > > droning - always starting at 70 mph up to at least 85 mph, and have > > > also sometimes heard it ~ 45 mph in 3rd, albeit a slightly different > > > tone. > > > > > > The noise is moderate in pitch and, at high speed, has a repetitive > > > frequency of less than 1 second. It reminds me of riding in a twin > > > engine airplane > > > > > > The noise completely abates when I push the clutch in, coasting at > > > high speed. > > > > Lance > > > 5 spd 3dr 125K > > I did do a moderate exhaust system ck a few days ago - no leaks, > components in relatively good cond (after replacing exhaust mani tube > to downtube flange gaskets), clearances seems okay, hangars good. > Altho it is lacking the wonderful exhaust note I recall in my 86 900T > (not sure if the turbo 'muffling' characterstics and/or exhaust > components are responsible for this). > Yes, the T8 sounds fantastic. > I've got another car up on the ramps right now, but will reinspect the > exhaust system soon. > > My main concern is that this might be an engine problem, which > hopefully seems the least likely, as will likely be replacing the > tranny sometime in the near future as a matter of course. Thought of engine mountings? Johan