G35 High Flow Cats And Test Pipe
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Test pipes replace the OEM catalytic converters (cats) which are the part that connect the cat-back exhaust to the headers... They are not a replacement for an exhaust.
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Veronatron (09-11-2019)
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Replace either the cats OR the cat-back and you will notice improvements.
Replace both and you will notice more improvements.
But yes, the stock cat-back is still restrictive if you just swap out the cats but you've removed a bunch of the restriction and its a lot easier for the engine to push the exhaust out.
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Yeah, I understand that the cats are very restrictive/dense... I'm not all too familiar with the G35 exhaust set up yet (noob to the Gs
). But you know, closer to the exhaust valves you are in the system, the hotter the exhaust, so I would think the further it gets away and cools off (and then expands) you would want the piping to get progressively bigger, and so I was thinking that if HFCs for the Gs have bigger inner diameters than OEM, and then you go from let's say a 3" HFC to a 2.25" catback section, it would be a restriction in the system.
But, if the cat honeycombs are a much bigger impediment to flow than just sheer diameter, that would make sense.
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But, if the cat honeycombs are a much bigger impediment to flow than just sheer diameter, that would make sense.