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Help with exhaust-pipes for 1979 Eldorado

Started by T.Skytte, January 15, 2018, 05:33:41 AM

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T.Skytte

Hi all,

I need to build/get a new complete exhaust for my 1979 Eldorado (V8 GAS).
I can find cat, muffler, resonator etc, but I'm having a little trouble finding the pipes though.  (also since they would have to ship to Spain).

If not too expensive I would like to do SS, 304 stainless to be exact.
So would anybody know where to get the pipes? I would intermediate-pipe and curvy-pipe (between muffler and resonator) as well as the end-piece-pipe. (maybe downpipes and t-piece as well but probably not necessary).

Very importantly, I will be installing myself probably, so all pipes must be *exactly* to spec. as I don't have pipe-bending capabilities.

Anybody know a reliable place? It needs shipping to Spain so it's not like if it doesn't fit I can just go there and get them to fix, it must fit first-time.

@Bruce Roe: I noticed in another thread you mentioned you put a 2 1/2" system on yours with a Borla muffler, would be great if you could expand with more details on this if you have the time? who made the pipes for you?

Finally, Walker has pipes (not SS though) but in their diagram it says the intermediate-pipe is for 1980 versions, anybody know if this is true? the 79 and 80 has the same engine so why would the intermediate pipe be different? Would this pipe fit in a 1979?

As always thanks a bunch for any input!

TS
----------------------------
1979 Eldorado Biarritz

Lars Kneller 8246

I've used Waldrons in Michigan for several cars, and all have fit well.

TJ Hopland

Lars, have you used them for a 79-85 Eldo?   There listings for those cars all at the least have incorrect years listed.   Its not just one listing that seems incorrect,  most of them don't seem plausible.  That doesn't inspire confidence.     

As to why 80 would be listed differently?   5.7 EFI gas would have been the CA only engine that year.   Most of the cars would have been the 6.0 DEFI or diesels.   The diesel I think had a different crossover arrangement than gas and would not have had a cat.   I wonder if maybe that 80 version had a different special CA version of the cat?   Maybe it was bigger than the 79 version? 

The diesel version waldron's has listed for two completely different body styles and only Seville would be interesting if it would fit your Eldo.   I think the diesel had a better Y setup and may have been slightly bigger.   I would think Seville and Eldo could use the same exhaust once they were the same platform. 

You could also try looking for 79-85 Toronado systems, probably 75% of those would have had a gas Olds V8 in em.   Riv's had a lot of V6 in the earlier years but later would have been the Olds V8's.         
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

smokuspollutus

Can't help with the stainless, but I can tell you if you go aluminized, you will save yourself a lot of aggravation by reading this

http://www.cadillacforums.com/forums/classic-cadillac-forum/885466-1984-eldorado-biarritz-project-thread-6.html
Post #78

Best of luck!

jsanford

For my '81 used Walker products from the cat back, purchased through RockAuto, did it all myself and am very happy.

The intermediate pipe probably changed in 1980 because they went to a different converter.
The original GM part numbers:
Intermediate Pipe 1979 - 25500712
Intermediate Pipe 1980 - 01618323
Converter 1979 - 08998692
Converter 1980 - 25056615

Jeremy

Jeremy
Sacramento, CA
1980 Seville
1981 Eldorado
2016 ELR

bcroe

#5
ts23, The 79 Toro system I built nearly 3 decades ago, used all 304 SS
which will last a lifetime (but check the hangers).  At 2  1/2 inches and
with a monolithic cat, there was a noticeable performance improvement. 
Some can hear a slight bit of "ting" noise from SS, I don't really notice
it.  Picture, the guy I sold it to is still very happy with it, on its 3rd car. 

I think a complete 5.7 diesel system would perform as well if you can
find one, and don't have inspection for the cat.  A system built from
400 series SS will last quite a while and can be bent on regular machines.
304 requires a mandrel bender.  Fed up with replacing exhaust systems,
I bought a Mig welder set up for SS and special bandsaw blades.  U
shaped pre bent 304 sections can be bought, which I cut off at the
needed angle and welded onto straight sections, to come with a
complete system.  For a DIY its a little more costly than a standard
system,  but pays for itself the first time you don't need to replace it. 

The 304 mufflers I used were off the shelf and not a particularly
great fit, my resonator is actually bigger than the muffler, to help
keep things quiet. 

The 79s had a Y pipe under the engine/trans, but some later years
used a cross over pipe ABOVE the trans, can't tell you which. 

Now my 79 Eldo has a 403 engine and TH425 trans, (from 78 Toronado),
so I built a 3 inch system, complete from manifolds to tail pipe.  Same
method, but it would not fit the original drive train.  The 4 hangers
were custom, took a bit of machine work and welding also. 

My own experience is, purchased systems usually don't fit perfectly,
something always need modification.  304 systems don't rust together,
I made punch marks (line of 4, 4 inches from end) to check that pipes
weren't working apart over the long term.  good luck, Bruce Roe

bcroe

About the picture of a SS 79 system.  The Y pipe sections shown are
factory.  They end at an angle for the 79 style cat, I bolted on my own
SS angle to straighten it out for this app.  All 304 SS from there back,
the discoloration could be polished off and they would look new. 

Bruce Roe

bcroe

#7
Quote from: bcroe
Now my 79 Eldo has a 403 engine and TH425 trans, (from 78 Toronado),
so I built a 3 inch system, complete from manifolds to tail pipe.  Same
method, but it would not fit the original drive train.  The 4 hangers were
custom, took a bit of machine work and welding also. Bruce Roe

I found these pictures of the 79 Eldo 3 inch system, of more interest may
be the hangers mostly fabricated to suspend it.  There is a hanger at each
end of each muffler, making sure the SS system stays in place.  Remember
SS may tend to work apart over the miles.  Biggest mufflers possible make
it quieter and flow better.  Note straight and curved sections welded
together, since the 304 can't be bent here.  Anyway, it proves even a terrible
welder can build an exhaust system (that nobody can see). 

The OX sensors allow monitoring the mixture delivered by the stock
fuel injection, not part of it.  Bruce Roe