Ractive 4 into 1 Headers are available NOW!!!

[tonkabui]

no way? there's no lower O2 bung? weird....

anyway, back to the question. if you use a MIL eliminator, you won't have to plug it in. if you want to tap the back of the exhaust to put the second O2 sensor in, where would you tap? the section of piping behind the cat is too short to put a bung in.

 

[Maxx Mazda]

no way? there's no lower O2 bung? weird....

Not really because Mazda has it there because it's right after the Cat. Putting it in without a Cat in place will still throw a CEL, so having a bung there is pointless.

 

[tonkabui]

Not really because Mazda has it there because it's right after the Cat. Putting it in without a Cat in place will still throw a CEL, so having a bung there is pointless.

i see what you are saying which makes perfect sense... but as with other headers, they are made for "race applications," ie. you're messing with your emissions equipment, which is illegal, so they include the second o2 bung so that it is a true "bolt-on" mod. it's actually more convenient this way though. finding a bolt to fill a dummy o2 bung is a pain in the arse.