Quote:
Originally Posted by T1T2GRE
So, for those of you who did the insulation in the trunk, did it also deaden the normal "nice" sound in the other gears? Or did it selectively delete the higher-gear drone issue? I was just wondering this morning if the nice tone we hear going through the gears will be muffled away with that fix.
|
The drone is simple resonance, that is frequency matching caused by natural vibrations of the engine, exhause gas and exhaust pipes. I submit that a simple change in the diameter of the piping, more or less, will eliminate the drone. Aircraft designers, bridge builders and any other structure is always designed with resonance in mind. Eventually it will damage or destroy the integrity of the material to which it impacts. Tightening the pipes will not help, wrapping them will only hide or surpress the noise, in order to make it go away the actual resonance needs to be cancelled. Think about two waves joining in sync... they get bigger. Now those two same waves can also cancel each other out. That is what you want. So... the natural vibration frequency of the engine at the point you hear the drone, just happens to match that of the exhaust piping. You would have thought the M team would have considered normal cruising RPM and adjusted the piping size accordingly.