I wanted a stainless steel exhaust system for a reasonable price for it to last the lifetime of my vehicle. Here is a comparison chart of exhaust materials from Summit Racing website
https://help.summitracing.com/app/answers/detail/a_id/4773/related/1
a1
My experience with the Walker aluminized steel connector pipe in Boston MA was 3 years which is the bottom of the range expressed in the chart. Best longevity is 304 stainless steel (which is non-magnetic) but I could not find a manufacturer that made a quiet OEM style replacement exhaust system for the Envoy 4.2L. The ones I saw were performance orientated and pricey. Next in the chart is 409 stainless steel (which is magnetic) with an expected life of 8 years. That looked good to me with much better lifetime than aluminized steel.
I could find only one manufacturer, Northeastern Exhaust, that made a stainless steel quiet / family / no growl type exhaust system. I wanted a clear unambiguous statement of what the connector pipe is made of. I did not want a repeat of Walker’s deceptive description of a stainless steel system where the connector pipe is actually made of aluminized steel. Distributor UPSW.com (mentioned in post #1 of this thread) did not respond to my inquiry.
The only seller I could find that clearly stated their product was an all 409 stainless steel system was Time Auto Parts on ebay.
http://rover.ebay.com/rover/1/711-5...0001&campid=5338077216&icep_item=282742894871
I sent them a private message for confirmation (shown below).
B1
C1
D1
Here is a picture of the exhaust system. It came nicely packaged in a box and arrived undamaged. I got it fast on the 2nd day after ordering on ebay.
001
002
003
004
All the pieces, except the pipe clamps, were marked stainless steel. Of particular interest was the connector pipe also marked stainless steel. I wish there was a simple definitive test for 409 stainless steel. It contains a lot of iron and is magnetic. It is called stainless steel because it contains 11% chromium and so, will resist rust better than plain steel or aluminized steel. My method for confirming if the parts were if fact made of 409 stainless steel was visual. On the connector pipe, I could see a glistening, where the tubing is clamped to form the bends, as if diamond dust was on the metal. I believe this is chromium sparkling, and so conclude to my satisfaction that it is indeed 409 stainless steel. On the muffler and resonator, I could see the tell tale soft dull sheen that only stainless steel sheet metal makes. I was satisfied everything, except the 2 pipe clamps, were made of 409 stainless steel. Also take note that the bends in the connector pipe are smooth inside mandrel bends compared to the Walker wrinkle bends.
005
006
007
Here are the part numbers:
008
009
010
The pipe outside diameters are as follows:
Catalytic flange pipe 2.855
Muffler entry 2.420
Muffler exit 2.625 .057 wall
Connecter pipe 2.495 .056 wall
Resonator entry 2.475 .056 wall
Resonator exit 2.530
Tailpipe 2.710
There is a neck down at the muffler entrance. The dimensions are no different than the old Walker system including the neck down.
011
012
I got an exhaust pipe tool set loaner from Advance Auto Parts. Thank you Advance Auto Parts. The Powerbuilt Kit 42 4pc. Exhaust Pipe Tool Set. A very nice high quality tool kit. I was tempted to buy it.
013
014
I tested the pipe fit and used the large expansion tool to get it to slip in. Better to do this on the shop floor rather than under the vehicle. I also marked the pipe full insertion length with a sharpie pen. It is always a wonder if you have fully inserted the pipe before clamping tight.
I jacked the vehicle on the passenger side and set the jack stands.
Removed the rear tire
Removed the frame cross bar that runs under the muffler.
I used the Powerbuilt cutter to sever the pipe near the muffler outlet. I was surprised how easy it was to cut.
Removed the two nuts from the muffler flange and tilted the muffler while wriggling the mounting bar from the rubber hanger. Came off without a problem.
Wriggled the connector pipe from the rubber hanger in similar fashion.
The resonator had fallen off all on its own from a rotten connector pipe.
Here is the old Walker Quietflow stainless steel exhaust system, 3 years in service in Boston MA. Note the connector pipe is aluminized steel and not stainless steel as name might imply. The muffler is pitted but solid, and the resonator is in excellent condition. I assume Walker used 409 ss to make the muffler and resonator.
015
016
Continued in next post