Wasted Potential Posted November 5, 2017 Share Posted November 5, 2017 I installed a nameless 5" muffler axleback and need to replace the factory flange from the midpipe. I had to hacksaw it in half and it is too thin/weak and leaking... Measurement from bolt center to center of the gasket = 3 & 7/16th" Measurement from inner most portion of circle diameter = 2 & 1/8th" Measurement from outer most portion of inner circle diameter = 2 & 1/4th" You can see the OE gasket within the picture just below the paper - notice the inner (reinforced) circle portion. I am presume that I need a "Stamped (not formed) flange with a 3 & 7/16th" bolt hole - center to center, with a 2 & 1/8th" inner diameter, OR 2 & 1/4th" diameter? I presume that I will have to angle grinder off the OE flange, and just weld the pipe to the flange - the welded portion will be outside (around) the pipe onto the outside of the hole for the new flange correct? Or, is the intent to have the pipe fit INSIDE the flange partially, and to weld the pipe outside to the flange... This seems simple, but I overthink everything. Thank you. Link to comment Share on other sites More sharing options...
Max Capacity Posted November 5, 2017 Share Posted November 5, 2017 There is a standard gasket from any auto parts store that will fit, they are like $7 each. I've used them a number times for that muffler to mid pipe joint. 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Wasted Potential Posted November 5, 2017 Author Share Posted November 5, 2017 I ended up purchasing the OE ones (were fairly cheap from Heuberger Subaru when I purchased the PCV cross over and vent rubber hoses. I am trying to find the actual metal flange at the moment though - not sure if to get a flange that is stamped or formed, and a confirmation that these measurements dictate a flange of 2 & 1/8th" ID Link to comment Share on other sites More sharing options...
59ctd Posted November 7, 2017 Share Posted November 7, 2017 https://fxexhaust.com/products.html Link to comment Share on other sites More sharing options...
Max Capacity Posted November 8, 2017 Share Posted November 8, 2017 Did you asked a local auto parts store what they can get ? 305,600miles 5/2012 ej257 short block, 8/2011 installed VF52 turbo, @20.8psi, 280whp, 300ftlbs. (SOLD). CHECK your oil, these cars use it. Engine Build - Click Here Link to comment Share on other sites More sharing options...
Wasted Potential Posted November 8, 2017 Author Share Posted November 8, 2017 Their books less them to obsolete part numbers in their systems. Ended up ordering I believe 31947 (?) From Amazon. I will update this when I have the flange in my hand next to the exhaust gasket. I'm worried the amount of weld bubble on the pipe to flange will not allow the nut to go all the way down on the bolt. Checked, it is 31947. Hope it won't rust away! Link to comment Share on other sites More sharing options...
JazzAvi8r Posted November 8, 2017 Share Posted November 8, 2017 since we are on the subject (yeah, totally threadjacking this for a sec), what gasket can I use to go from the Cobb catted DP to a borla CBE? the gasket that came with the grimmspeed gasket kit doesn't fit. something about a donut gasket? Link to comment Share on other sites More sharing options...
rougeben83 Posted November 8, 2017 Share Posted November 8, 2017 standard flange design is to have it slip over the pipe. Measure the outer diameter of your pipe and get the flange with the matching inner diameter. It will be more stable that way. EDIT: if you had to cut off additional pipe w/ the flange, you may have better luck with an intermediate pipe that can slip over your current exhaust pipe. Link to comment Share on other sites More sharing options...
Wasted Potential Posted November 9, 2017 Author Share Posted November 9, 2017 Link to comment Share on other sites More sharing options...
Wasted Potential Posted November 9, 2017 Author Share Posted November 9, 2017 I feel these flanges are 1/8th" too wide in regards to inner diameter, therefore, I hope the pipe will fit into it partially and I will tack it in place then supply a proper bead around it. The OE gaskets for these mid section to axle backs has an inner diameter of 2", not 2.125" it seems. However, I could not find a flange that had adequate bolt center to center diameter, so I will attempt to utilize these with a minor amount of copper gasket maker. Additionally, notice the slight bend to the flange face, I believe they were not cooled quick enough OR just poor craftsmanship... We will see how it goes... EDIT: after thinking about how the gasket may impede flow, I think back to the mid section that is one pipe at 2.5" diameter.... Two tail sections at 2" will not compromise any flow compared to a factory cat, or even a hi flow cat at a 2.5" diameter... Link to comment Share on other sites More sharing options...
Wasted Potential Posted November 9, 2017 Author Share Posted November 9, 2017 standard flange design is to have it slip over the pipe. Measure the outer diameter of your pipe and get the flange with the matching inner diameter. It will be more stable that way. EDIT: if you had to cut off additional pipe w/ the flange, you may have better luck with an intermediate pipe that can slip over your current exhaust pipe. I also worry that the bend going to this section will be to severe to purchase a flange with a straight section... But, then again, it has been a few weeks since I looked at it! Link to comment Share on other sites More sharing options...
59ctd Posted November 9, 2017 Share Posted November 9, 2017 I also worry that the bend going to this section will be to severe to purchase a flange with a straight section... But, then again, it has been a few weeks since I looked at it! If you get one of the exhaust flanges with short pipe you can probably cut the pipe shorter so that it works with the curve/bend that you mention. Link to comment Share on other sites More sharing options...
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