Comments on Stainless Steel Exhaust Manifold
Comments on Stainless Steel Exhaust Manifold
(OP)
I started to make Stainless Steel exhaust/ turbo charger manifolds for the Cummins Turbo Diesel found in the Dodge pickups. I saw a prototype and the comments were that the use of this piece vs. the stock cast iron piece was a drop in exhaust gas temperatures by several hundred degrees F. The fabricator had used Schedule 10 stainless steel 1 1/2 inch elbows and pipe to make his piece. I have done the same on the manifold in the attached picture. Schedule 10 SS comes in 304 and 316 alloy. I have both available and made my first prototype from 304. So far so good. I have it on my test mule (2000 Ram 2500 2WD, with bigger than stock turbo and injectors and custom air box, 271,000 miles). One of the performance ss exhaust material suppliers suggests using 321 alloy for applications like mine. Exhaust gas temperatures can exceed 1400 F. I am wondering if using readily available, and reasonably priced schedule 10 304 or 316 alloy elbows makes sense? I have purchased some 2 inch .065 wall 321 tubing from the supplier. It allows me to build a much less restrictive manifold, is lighter in spite of being larger and seems to hold up fine. Comments?
Flying Hammer LLC a hot rod fabrication facility in Lincolnton, NC
www.flyinghammerllc.com





RE: Comments on Stainless Steel Exhaust Manifold
RE: Comments on Stainless Steel Exhaust Manifold
Well I completely typed that sentence wrong! What I meant was that carbon will form a carbide with titanium before it does with chromium. Sorry for the misprint.
RE: Comments on Stainless Steel Exhaust Manifold
Clark
Flying Hammer LLC a hot rod fabrication facility in Lincolnton, NC
www.flyinghammerllc.com
RE: Comments on Stainless Steel Exhaust Manifold
2. The lighter the walls the better. The tubing may distort a bit more, but there will be less stress and less risk of thermal fatigue cracking.
If there is a way to open up the center bridge between the flanges so that it is not in contact with the tubes it would further help. You don't care if the tubes distort.
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Plymouth Tube
RE: Comments on Stainless Steel Exhaust Manifold
1- The first design uses the Schedule 10 304/304L SS 1 1/2" elbows and pipe. The OD is 1.88, with 0.109 wall thickness. I can tolerate some small amounts of warpage or distortion. I simply resurface the exhaust and turbo flange on a Zirconium belt. In the orignal configuration, limited distance between the exhaust mounting surface and the turbo flange, this smaller pipe is all that will fit.
2- The second design uses 321 alloy 2" tubing with a .065 wall. I use the 347 filler rod when tig welding 321. I use this design when I can move the turbo flange away from the cylinder head. This allows the use of non-stock larger diameter turbo compressors. In many of these applications, spacers have been used to move the turbo away from the manifold.
Flying Hammer LLC a hot rod fabrication facility in Lincolnton, NC
www.flyinghammerllc.com