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A Loud Imperial?

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Greetings, Imperial Fans and Experts.


I purchased a 1968 Imperial Crown hardtop sedan in January 2021. It is a single exhaust pipe car. When I bought it, it had a performance muffler; it looked like a cherry bomb from the era. The car was very loud, of course. Altering the car to give it proper Imperial manners was top priority. I may have made a mistake right off the bat . . . I had dual exhausts installed with ordinary mufflers at a local exhaust shop. The system included a pre-fabricated X-pipe. The car was less noisy, but still, way louder than I remember my mother's '68 Crown; that car seemed to whisper going down the road. Mom's was a single exhaust car. A second attempt to quiet the car also failed: the X-pipe was removed, larger mufflers and a pair of resonators were installed. I couldn't notice any difference. 


Finally, I learned that Chrysler produced special mufflers for Imperials, those 30-inch long monsters. I found them at Waldrons Exhaust. With much frustration, I ordered the entire dual exhaust system from Waldrons. After installation, I was deeply disappointed that my Crown, though a little better, still roars in comparison to what I remember in 1978, the last year I drove Mom's Crown. What have I done? What have I not done? 


When trying to quiet down my '66 Charger, a short H-pipe connection where the dual pipes get close together made a noticeable difference. I'm considering the same with this Imperial, but I beseech the experts here for wisdom before proceeding. Thank you.


PS: The original wheel covers are stowed away, preserved for car shows. What you see here are a set of wire wheel covers from a 1975 (?) New Yorker or Dodge Diplomat, a good look for touring and pleasure cruising.


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I have no real input other than maybe cars today are just quieter than 40 years ago and that your memory has changed?   I would think a new exhaust should have quieted things down (depending on the internals of the mufflers).

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I would start by making sure none of the exhaust parts are grounded to the chassis, and also that all the supporting bracketry (specifically the rubber insulators) is not hardened, and still supple. I suspect it is not the exhaust “note” that you hear, but rather the transmitted vibration from the exhaust to the chassis.


Also remember that the original insulating materials all over the car are deteriorated and hardened, and probably not doing their job as well as when new.

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Thanks, alsancle and Lee.


The exhaust system bracketry is all new. Once in a while I heard a knock that is clearly a pipe bumping the chassis, but that is rare. 

I agree that the sound insulating materials of the car may not be absorbing noise as well as when new.


And, as suggested, my memory of my Imperial driving experiences of 1975 may not be accurate. I sure did expect those big mufflers to meet my expectations. Were those huge mufflers used on other Chrysler automobiles, like Plymouth Furys? If so, I would question if there were police cruiser versions available; just brainstorming here.


I plan to visit Auburn, Indiana, during the ACD Festival; I have a friend there who knows Imperials pretty well. He has a nice '69 model. Perhaps I ought to bring my Crown this year for his ear to consider. I usually bring my '66 Charger (see below). Yeah, that's me between Mr. and Mrs. Hemi. 


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