Date: 26 Nov 2002 05:26:36 -0800 From: alancemornopsamo.com (Lance Morgan) Subject: Re: c900 harmonic droning?
Four Weis <mweinopsamcom> wrote in message news:<3DE2B8B7.BD1A2F11nopsamcom>... > Lance Morgan wrote: > > > 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 > > Saabs were based on airplanes and Saab must have made prop planes at one > time :-) > > This sounds like it could be tires, but because it sounds the same in 3rd > at 45 and I assume 5th at 70 - I would have to say engine drive shaft > related since it appears to happening at a specific rpm. > > > > > > > The noise completely abates when I push the clutch in, coasting at > > high speed. > > I've heard it twice in 3rd, and consistently in 5th through whatever the 70 to + 85 mph corresponding RPM range is (I did jot down some RPM #s, but can't find them right now, from a high-speed tollway). But I haven't heard it in 4th (or any other gear), at similar RPM. Probably the only rotating mass I could semi-easily test or change is the flywheel. Any other test/isolation suggestions?