A Loud Imperial?

[OldChargerGuy]

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.

[alsancle]

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).

[Lee H]

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.

[OldChargerGuy]

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. 

[TTR]

Just a few weeks ago, I replaced a +/-20 year old exhaust system in a 1960 Chrysler 300F by fabricating & forming everything to factory configuration + new correct OEM size mufflers supplied by local vendor and to much of my disappointment, it is now noticeably louder than the one I took out, which had less than 5K miles, but was internally quite rusted due to infrequent and short use periods (and was constructed/formed in a typical cheap-quick-n-dirty muffler shop fashion).

I believe this "louder" sound is simply due to cheaper made mufflers with less insulation.

 

OTOH, I'm currently installing annoyingly loud straight, custom-made "Race" type pipes (which I fabricated couple of years ago) into a pretty much otherwise stock and fully/correctly restored (by me) '71 4-cam V12 Ferrari, merely because the current owner likes it LOUD !! 🙄

 

 

Edited June 19 by TTR (see edit history)

[OldChargerGuy]

Thanks, TTR.

Your hypothesis could explain the extra noise . . . cheap modern manufacturing. 

I trust your client with the '71 Ferrari gets along exceedingly well with his neighbors. He may not soon. 

 

I recorded an interesting video of moving my cars back to my driveway after tree-trimming was done. It is very revealing.

I'll post a link later.

[TTR]

Couple of years ago, after fabricating the aforementioned "Race" type exhaust and my previously fabricated, a bit milder "muffler delete" set up for that car (which the owner thought of being too quiet !?!), I audio/video recorded all three different variations, i.e. stock, muffler deleted (but w/tailpipes & resonators) and "Race" (basically straight pipes exiting before rear tires) by driving same exact route, using same gears and speeds for each session along with two decibel meters.

My wife edited all three sessions into a nice comparison compilation.

Sorry, but I won't post/share it here or elsewhere publicly. Only I and the car owner have copies and he has agreed not to post or digitally share it with anyone without my permission. 

 

P.S. I believe the car owner gets along fine with his neighbors since the car gets taken out for brief pleasure drives only few times during a winter (and when I have it for maintenance off season, i.e. summer).

[OldChargerGuy]

I recently had to replace my home's roof and remove a few trees following some damage after a strong wind storm. While the tree-felling was going on, I had moved my cars out of harm's way and setup a tripod and camera to capture some action. When all was clear, I moved the cars back to the driveway. The camera was handy, so I filmed their return. The sounds that I heard shocked me, to the point that RitaMary will not be going to the family picnic reunion unless she sounds like a proper Imperial. 

 

You may listen with this link. Please let me know if access isn't working.

https://drive.google.com/file/d/1PyLPZM4tnQuuXtw4VwBoXhpz4tByrWci/view?usp=sharing

[Lee H]

Something about that sound makes me think of a leaky exhaust manifold gasket. Or a cracked manifold. 

[Dosmo]

Admittedly, I'm not a knowledgeable person about such matters.  I have no idea why that beautiful Imperial sounds the way it does, but I think something is amiss here.  I don't believe a car of that age with a recently replaced exhaust system by a professional company should sound like that.

 

Heck, the Charger is noticeably quieter than the Imperial.  I did hear the clunk of what I would guess to be the exhaust when you pulled the Charger into the driveway.  But, the exhaust note of the Charger sounds mostly like what I remember these cars sounding like when there were plenty of them on the road.

 

The Imperial sounds like there is something causing a nasty exhaust leak under the hood.  The sound I hear doesn't match the image I see.  The exhaust note is reminiscent of the dogged out 90s pickup trucks that populate a good part of the traffic where I take my household trash.

 

Boy, that is one nice Imperial, regardless of how it sounds.  👊

Edited July 16 by Dosmo (see edit history)

[8E45E]

What I get out of this is your hearing is still fantastic for your age.    Just be thankful for that!

 

Craig

[Dosmo]

54 minutes ago, 8E45E said:

What I get out of this is your hearing is still fantastic for your age.    Just be thankful for that!

 

Craig

Yes, I am very thankful that I can still hear pretty well, although I don't know about it being fantastic - I would probably describe my hearing as mostly adequate.  On this, my wife would heartily disagree.  😄 

[TTR]

On 7/7/2024 at 9:45 AM, OldChargerGuy said:

I recently had to replace my home's roof and remove a few trees following some damage after a strong wind storm. While the tree-felling was going on, I had moved my cars out of harm's way and setup a tripod and camera to capture some action. When all was clear, I moved the cars back to the driveway. The camera was handy, so I filmed their return. The sounds that I heard shocked me, to the point that RitaMary will not be going to the family picnic reunion unless she sounds like a proper Imperial. 

 

You may listen with this link. Please let me know if access isn't working.

https://drive.google.com/file/d/1PyLPZM4tnQuuXtw4VwBoXhpz4tByrWci/view?usp=sharing

Imperial appears to sound like it has inefficient (read crappy) mufflers (kind of like I mentioned with my project), but also severe leaks either at manifolds and/or throughout various exhaust connector flanges/joints (read crappy installation). 

Not only would I recommend looking for better quality mufflers, but also for a different "professional"(?) installer (i.e. someone able to tell the difference and advise you, not only how to do it correctly, but also capable of doing it too, of course assuming you're willing pay for the job done right, not matter what).