Droning is by definition acoustic and a result of something tuning up. New Yorkers and Imperials with the same size engines had additional resonators to break up the pulses. Sometimes it is the angle of the exhaust. If tilted down, it may drone off the pavement and straight outlets might help. I suggest put the car on a rack with a nice hot exhaust?even leaving the engine running?to see if anything is touching when it should not. Massaging the system with a pry bar might tell you if some tubing or the muffler shell are tuning up. Exhaust piping in a bind can tune up like a violin string. Loosening clamps might allow something tight to loosen up. In the real world of gas compressor piping, resonance can be broken up by installing a restriction in the piping?like a 1 ½? disc in 3? piping. Excess pressure drop will be minimal and ,if properly placed in the system, can permanently eliminate the droning. This would be a hidden fix, invisible to the beady eyes of the judges. Let us know what works. Rich From: Chrysler300@xxxxxxxxxxxxxxx [mailto:Chrysler300@xxxxxxxxxxxxxxx] On Behalf Of Terry Mctaggart Sent: Sunday, May 06, 2012 2:22 PM To: Listserver Chrysler Club Subject: [Chrysler300] Exhaust Noise A few years ago, I installed a new exhaust system on my 300F, from the headers on back. Although there are no exhaust leaks, the car drones while driving. When new, did Chrysler install special "soft" hangars on the exhaust system to eliminate any possible resonance with the then-new unibodies? Terry McTaggart [Non-text portions of this message have been removed] [Non-text portions of this message have been removed] ------------------------------------ To send a message to this group, send an email to: Chrysler300@xxxxxxxxxxxxxxx To unsubscribe from this group, send an email to bob@xxxxxxxxxxxxx or go to http://autos.groups.yahoo.com/group/Chrysler300/join and select the "Leave Group" button For list server instructions, go to http://www.chrysler300club.com/yahoolist/inst.htm For archives go to http://www.forwardlook.net/300-archive/search.htm#querylangYahoo! Groups Links <*> To visit your group on the web, go to: http://groups.yahoo.com/group/Chrysler300/ <*> Your email settings: Individual Email | Traditional <*> To change settings online go to: http://groups.yahoo.com/group/Chrysler300/join (Yahoo! ID required) <*> To change settings via email: Chrysler300-digest@xxxxxxxxxxxxxxx Chrysler300-fullfeatured@xxxxxxxxxxxxxxx <*> To unsubscribe from this group, send an email to: Chrysler300-unsubscribe@xxxxxxxxxxxxxxx <*> Your use of Yahoo! Groups is subject to: http://docs.yahoo.com/info/terms/