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1980 Eldorado exhaust

Started by TLonstad, March 16, 2021, 10:21:44 AM

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TLonstad

Hi. I've a 1980 triple black Eldorado with the 368 DEFI engine.

One of the former owners has changed the exhaust, problably due to age, but the cathalytic converter is removed, and the muffler is a Walker 18390 (sound FX) and the resonator is a Walker 22140.

The problem is exhaust drone at speeds and under engine load. I changed the muffler to a AP 3034 and the resonator to a AP 3035, but it's still the same problem.

I need som advice for a quiet, factory exhaust note. Walker doesn't make a "quiet flow" muffler for this e-bodies anymore, but maybe I can fit a quietflow from a 96-98 Grand Cherokee or somerthing. I live in Norway, so it's not cheap to do some hit and miss.

regards.

TJ Hopland

Walker lists a different resonator for the diesels,  the 18312.   Maybe that would be a bit quieter?    Otherwise you may have to look at installing a cat,  those did change the sound.
StPaul/Mpls, MN USA

73 Eldo convert w/FiTech EFI
80 Eldo Diesel
90 CDV
And other assorted stuff I keep buying for some reason

TLonstad

Thanks for the reply. Yes, I will install a Cathalytic converter, I'm going to order some things from the states, shipping it by space in a container. But I'll have to buy the right parts.

The dieselengines was without Cat, so maybe it will be a little quieter. I have used quiet flow on some american cars before, with good results. So I'm thinking of finding a Walker "quiet flow" from another car that will fit. The 75-78 Eldorado has a "quiet flow" muffler available at Rockauto, it seems to fit, but the inlet is in the center. I maybe have to deal with that.

81 BENY Biarritz

Just in case you don't have it, here are the Parts Drawings and Part Numbers from the 1976 THRU 1981 CADILLAC PARTS ILLUSTRATIONS CATALOG.   Maybe they will be of some help in regards to crossing over part numbers or for the general reference regarding the components and routing of the original exhaust systems.   
Hope it is of some help.  Dave
PS.  By the way Triple Black is a very nice and unique colour combo!   Any chance it is also a Biarritz?


bcroe

My policy has been, to use the biggest mufflers I could fit into the
space, for quieter operation without loss of performance.  Bruce Roe

TLonstad

Quote from: 81 BENY Biarritz on March 16, 2021, 06:12:41 PM
Just in case you don't have it, here are the Parts Drawings and Part Numbers from the 1976 THRU 1981 CADILLAC PARTS ILLUSTRATIONS CATALOG.   Maybe they will be of some help in regards to crossing over part numbers or for the general reference regarding the components and routing of the original exhaust systems.   
Hope it is of some help.  Dave
PS.  By the way Triple Black is a very nice and unique colour combo!   Any chance it is also a Biarritz?

Thank you. I've the shop manual, but not the parts book.

TLonstad

Quote from: smokuspollutus on March 16, 2021, 06:56:29 PM
https://www.cadillacforums.com/threads/puttin-on-the-ritz-1984-eldorado-biarritz-project-thread.885466/page-4

Read post 78

Anthony

Thanks, I've read it, but he used a AP with the Walker resonator, that's like what I'm using right know. It's not very loud, but it have a drone under load until about 60 mph.

TLonstad

Quote from: bcroe on March 16, 2021, 08:24:59 PM
My policy has been, to use the biggest mufflers I could fit into the
space, for quieter operation without loss of performance.  Bruce Roe

Yes, I'm thinking about fit a muffler for a 96 Grand Cherokee under there. it's a little bit bigger than the "Sound FX" that I've under there now, but it's a "Quiet flow" muffler.


79 Eldorado

Years ago I was getting a custom exhaust on a car at a place in Canada. I wanted it to be quiet while still flowing as freely as possible. I asked them to give me the largest mufflers they could reasonable fit (dual exhaust pre-catylist car). Whatever you select I second what Bruce mentioned, within any specific type, the bigger the better (longer) if you want quiet. I think they were using Walker although they appeared unbranded as I recall (I finally sold that exhaust).

Walker has a really nice search tool:
https://www.walkerexhaust.com/universal-muffler-search.html

Walker muffler types with descriptions:
https://www.walkerexhaust.com/products/light-vehicle/mufflers-muffler-assemblies.html

There was also an article on an LS forum where they referenced a mustang forum. Someone took the time to try 17 set-ups on the same car and they measured HP/ torque at both idle and 2000RPM on a dyno. That's an incredible amount of work. Each of the mufflers were traditional performance muffler so likely louder than anything you are considering but I was shocked by the effort and thought I would mention it.

I also found this article; still performance related but given the website name with the premise of quiet:
https://soundproofnation.com/quietest-performance-muffler/

Scott

bcroe

My own choice of mufflers has been more limited, because I only use
304 stainless.  Many decades ago, I got fed up with maintenance of
exhaust systems that seemed to be always falling off my cars.  I decided
that any failure would be replaced by 304 parts, put together by me one
last time.  304 pipes, pre bent section, mufflers could be assembled with
the right band saw blades and a MIG welder with SS wire and the right
gas.  Most of the systems I built from then to now are still in service, in
some cases moved along to as many as 3 cars. 

In the case of the 79-85 E car, there is really only space for a single
exhaust, mine is 3 inch.  My mufflers are not an ideal fit, and it is not
completely silent, but the exhaust is not something you notice.  Bruce Roe

smokuspollutus

Quote from: TLonstad on March 20, 2021, 04:10:01 AM
Thanks, I've read it, but he used a AP with the Walker resonator, that's like what I'm using right know. It's not very loud, but it have a drone under load until about 60 mph.

Did you use the AP MSL series? That is the equivalent to the Quiet-Flo.

Alternatively you can use a complete Walker Sound FX system without the drone. I've driven cars with both and the SoundFX is just barely louder at idle. The resonator is smaller with the SoundFX.

TLonstad

Quote from: 79 Eldorado on March 21, 2021, 11:41:47 AM
Years ago I was getting a custom exhaust on a car at a place in Canada. I wanted it to be quiet while still flowing as freely as possible. I asked them to give me the largest mufflers they could reasonable fit (dual exhaust pre-catylist car). Whatever you select I second what Bruce mentioned, within any specific type, the bigger the better (longer) if you want quiet. I think they were using Walker although they appeared unbranded as I recall (I finally sold that exhaust).

Walker has a really nice search tool:
https://www.walkerexhaust.com/universal-muffler-search.html

Walker muffler types with descriptions:
https://www.walkerexhaust.com/products/light-vehicle/mufflers-muffler-assemblies.html

There was also an article on an LS forum where they referenced a mustang forum. Someone took the time to try 17 set-ups on the same car and they measured HP/ torque at both idle and 2000RPM on a dyno. That's an incredible amount of work. Each of the mufflers were traditional performance muffler so likely louder than anything you are considering but I was shocked by the effort and thought I would mention it.

I also found this article; still performance related but given the website name with the premise of quiet:
https://soundproofnation.com/quietest-performance-muffler/

Scott

Thank you, that's a lot of information at those links, but it's good information. Thank you againg.

TLonstad

Quote from: smokuspollutus on March 21, 2021, 02:46:30 PM
Did you use the AP MSL series? That is the equivalent to the Quiet-Flo.

Alternatively you can use a complete Walker Sound FX system without the drone. I've driven cars with both and the SoundFX is just barely louder at idle. The resonator is smaller with the SoundFX.

Are you sure about this? I thought the AP MSL series was the equivalent to the Walker Sound FX?

I bought the AP 3034 Challenge LTW. Maybe that is what is wrong?

TLonstad

Quote from: bcroe on March 21, 2021, 12:41:19 PM
My own choice of mufflers has been more limited, because I only use
304 stainless.  Many decades ago, I got fed up with maintenance of
exhaust systems that seemed to be always falling off my cars.  I decided
that any failure would be replaced by 304 parts, put together by me one
last time.  304 pipes, pre bent section, mufflers could be assembled with
the right band saw blades and a MIG welder with SS wire and the right
gas.  Most of the systems I built from then to now are still in service, in
some cases moved along to as many as 3 cars. 

In the case of the 79-85 E car, there is really only space for a single
exhaust, mine is 3 inch.  My mufflers are not an ideal fit, and it is not
completely silent, but the exhaust is not something you notice.  Bruce Roe

I regret that I didn't go stainless with my 67 Riviera some years ago. I bought the muffler and resonnators from Waldrons exhaust. It's a dual and it's really nice and quiet.