Tired of searching for individual exhaust system components. Time to consolidate info:
The exhaust system starts at the head, with its five exhaust ports (note location and number of the exhaust manifold studs, there are 16, one is hidden):
Photo courtesy of Tom S. of RS2 America fame
The exhaust manifold to head studs are Item 9 in this diagram:
The OE 3B, AAN and ABY manifold and gaskets:
The OE 3B, AAN and ABY Manifold has runners from Cylinders 1 and 5 that rise up to connect to the EM just under the WG flange. This is not good for flow and may be a cause for burning exhaust valves on 1 and 5 when adding a chips set, e.g. MTM Stage 1+ without changing the EM for an upgraded unit, e.g. RS2 manifold:
Photo courtesy of Tom S. of RS2 America fame
Here is a photo that shows the RS2 EM on top and the OE AAN (and 3B and ABY) EM on the bottom to show the difference in the way cylinders 1 and 5 are handled:
Photo courtesy of GoHeels on Audiworld
Here are some OE AAN (and ABY) EM flow numbers courtesy of 034:
The RS2 Exhaust manifold is much flatter and eliminates the two separate runners from Cylinders 1 and 5. This is a serious upgrade from the OE AAN exhaust manifold.
RS2 EM Flow photo courtesy of 034
RS2 EM PNs:
Installation of an RS2 manifold requires some studs to be shortened:
Other options include the Wagner/034 RS2 HO manifold and a cast log manifold from STR. Beware that all of the aftermarket OE manifolds including the RS2, the Wagner EMs and even the STR manifolds have been copied and are out there on eBay to catch the unware.
The Wagner/034 RS2 HO manifold:
Photo courtesy of 034
An STR cast log EM:
The AAN exhaust system after the exhaust manifold includes the WG dump pipe connection and a down pipe that starts out as a single pope but splits as a "Y" and goes to the two catalytic converters(Note: The "Y" portion of the downpipe comes with a metal insulation cover when new. By now, most of these have corroded and fallen off, at least partially. Common source of rattle). Here is the C4 front exhaust details:
Here is the 3B S2 equivalent:
Here is the ABY S2 equivalent:
Here is the RS2 equivalent (note: the down pipe is bigger than the ABY in the A80Q chassis):
Here is a photo of Dan T's (Ringbearer's) old OE AAN downpipe "Y" and catalytic converters showing the last reminant of the OE insulation cover:
Here is some C4 AAN middle and final exhaust system info:
Here is one photo of the stock C4 AAN exhaust system:
Photo courtesy of Dustovich in Edmonton, Alberta, Canada.
REF for flow numbers: Exhaust Manifold Flow Numbers courtesy of 034.
Thanks to those not named who posted up the photos and diagrams used in this post.
The exhaust system starts at the head, with its five exhaust ports (note location and number of the exhaust manifold studs, there are 16, one is hidden):
Photo courtesy of Tom S. of RS2 America fame
The exhaust manifold to head studs are Item 9 in this diagram:
The OE 3B, AAN and ABY manifold and gaskets:
The OE 3B, AAN and ABY Manifold has runners from Cylinders 1 and 5 that rise up to connect to the EM just under the WG flange. This is not good for flow and may be a cause for burning exhaust valves on 1 and 5 when adding a chips set, e.g. MTM Stage 1+ without changing the EM for an upgraded unit, e.g. RS2 manifold:
Photo courtesy of Tom S. of RS2 America fame
Here is a photo that shows the RS2 EM on top and the OE AAN (and 3B and ABY) EM on the bottom to show the difference in the way cylinders 1 and 5 are handled:
Photo courtesy of GoHeels on Audiworld
Here are some OE AAN (and ABY) EM flow numbers courtesy of 034:
The RS2 Exhaust manifold is much flatter and eliminates the two separate runners from Cylinders 1 and 5. This is a serious upgrade from the OE AAN exhaust manifold.
RS2 EM Flow photo courtesy of 034
RS2 EM PNs:
Installation of an RS2 manifold requires some studs to be shortened:
Other options include the Wagner/034 RS2 HO manifold and a cast log manifold from STR. Beware that all of the aftermarket OE manifolds including the RS2, the Wagner EMs and even the STR manifolds have been copied and are out there on eBay to catch the unware.
The Wagner/034 RS2 HO manifold:
Photo courtesy of 034
An STR cast log EM:
The AAN exhaust system after the exhaust manifold includes the WG dump pipe connection and a down pipe that starts out as a single pope but splits as a "Y" and goes to the two catalytic converters(Note: The "Y" portion of the downpipe comes with a metal insulation cover when new. By now, most of these have corroded and fallen off, at least partially. Common source of rattle). Here is the C4 front exhaust details:
Here is the 3B S2 equivalent:
Here is the ABY S2 equivalent:
Here is the RS2 equivalent (note: the down pipe is bigger than the ABY in the A80Q chassis):
Here is a photo of Dan T's (Ringbearer's) old OE AAN downpipe "Y" and catalytic converters showing the last reminant of the OE insulation cover:
Here is some C4 AAN middle and final exhaust system info:
Here is one photo of the stock C4 AAN exhaust system:
Photo courtesy of Dustovich in Edmonton, Alberta, Canada.
REF for flow numbers: Exhaust Manifold Flow Numbers courtesy of 034.
Thanks to those not named who posted up the photos and diagrams used in this post.
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