Anaconda 02 bung placement. What gives?
- Thread starter Anthony
- Start date
Blue Moon Sonic
New member
It's because the primary cat does all of the work when cleaning the exhaust of anything poisonous while the secondary cat is there to make make sure everything is clean. There will be no O2 sensors by the secondary cat. I do honestly think the secondary cat is only there as a sound damper for the exhaust. I could be wrong but there are 2 catalytic converters in this bloody thing.
Last edited:
Blue Moon Sonic
New member
The anaconda down pipe is actually catless. If you look at the stock one, there is a catalytic converter between the 2 sensors.. The first O2 sensor is for air that is leaving the exhaust manifold. The second O2 bung is the outflow after the initial reading from the first sensor to make sure that the cat isn't plugged up or reading the same as the first o2 sensor. The 3rd bung is for a wide band sensor. Like I said before. I could be wrong.
But there needs to be a sensor after the high flow cat in order to get a reading for emissions, no? It just seems like the utility of the system would vastly improve if there were an 02 bung AFTER the cat as well as before it. How am I supposed to test emissions with it like this?
Dubbs_RS
New member
2 of the holes are basically there so you have something to hook your existing O2 sensors into. The 3rd is for a wideband O2 sensor. Unless you have one of those, you'll simply plug the 3rd.
From MPFab's site: "This “competition” downpipe deletes the restrictive primary catalyst and replaces the secondary catalyst with extremely high flowing 100 cell MPFab unit." You are not going to get a clean emissions reading because you are running a catless downpipe (this is the same for ZZP's and BNR's catless downpipes). Even if there was a hole after the secondary cat for you to plug an O2 sensor into you probably wouldn't get a clean reading because the primary cat is responsible for most of the cleaning of the exhaust.
So you have a few options... 1) Live with a perpetual CEL... 2) Disable the O2 sensors using Trifecta's software (if you're tuned)... 3) I have had success running a Vibrant J-Fitting. This moves the second O2 sensor out of the exhaust stream and tricks it into reading clean.
Hopefully this clears things up for you a bit. 2 of those holes are where they are simply because they have to be to accommodate existing sensors.
From MPFab's site: "This “competition” downpipe deletes the restrictive primary catalyst and replaces the secondary catalyst with extremely high flowing 100 cell MPFab unit." You are not going to get a clean emissions reading because you are running a catless downpipe (this is the same for ZZP's and BNR's catless downpipes). Even if there was a hole after the secondary cat for you to plug an O2 sensor into you probably wouldn't get a clean reading because the primary cat is responsible for most of the cleaning of the exhaust.
So you have a few options... 1) Live with a perpetual CEL... 2) Disable the O2 sensors using Trifecta's software (if you're tuned)... 3) I have had success running a Vibrant J-Fitting. This moves the second O2 sensor out of the exhaust stream and tricks it into reading clean.
Hopefully this clears things up for you a bit. 2 of those holes are where they are simply because they have to be to accommodate existing sensors.
I think you've answered my question. Thanks a lot. If anyone has any other opinions or something to add, please. I'll be checking back.
Preloader
The M32 Martyr
The stock exhaust has two o2 sensors,
1st- immediately after turbo/before primary cat:
Reads air-to-fuel ratio for the computer to adjust fuel duty.
2nd- after primary cat/before 2nd cat:
Detects failure of primary cat. Has nothing to do with readings for fuel adjustments.
1st- immediately after turbo/before primary cat:
Reads air-to-fuel ratio for the computer to adjust fuel duty.
2nd- after primary cat/before 2nd cat:
Detects failure of primary cat. Has nothing to do with readings for fuel adjustments.
ScarabEpic22
Member
You need to think of the Anaconda as a catless downpipe that retains the factory midpipe cat configuration. I.e. the upstream and downstream O2 sensors do NOT have the primary catalytic converter between them (as you've noticed). Realistically, you could remove the rear O2 sensor as it's only purpose is to check primary catalytic converter performance and use it as a WBO2 bung.
As Dubbs said:
1) Remove the codes with every flash if you have the Trifecta tune
2) buy a j-pipe extension
3) turn them off via HPTuners/EFILive.
4) live with the CEL? (Wouldnt recommend this, you'll never know if you have another issue...)
The 2nd/rear catalytic converter that the Anaconda has is (IMO) for reducing smell and does some cleaning of the exhaust. Coming from a (different) catless vehicle, I know how annoying it can get in stop and go without any cats. Walker would have to chime in, but Im betting this is his rationality for including one with the Anaconda.
As Dubbs said:
1) Remove the codes with every flash if you have the Trifecta tune
2) buy a j-pipe extension
3) turn them off via HPTuners/EFILive.
4) live with the CEL? (Wouldnt recommend this, you'll never know if you have another issue...)
The 2nd/rear catalytic converter that the Anaconda has is (IMO) for reducing smell and does some cleaning of the exhaust. Coming from a (different) catless vehicle, I know how annoying it can get in stop and go without any cats. Walker would have to chime in, but Im betting this is his rationality for including one with the Anaconda.
Dubbs_RS
New member
Really I was never suggesting that either... Just was saying it is technically an option. I got the J-Fitting specifically to eliminate that nasty CEL.
Thanks guys for the help clarifying this for him. Ya'll taking your own time to help my customer is pretty amazing.
I've said exactly the same stuff in the PMs I've received from him on the subject. His mechanic thinks I'm a dummy for building it this way, and apparently, his mechanic keeps pushing that with Anthony. This has lead to several PMs asking why I did it like this and that "the system doesn't make any sense")his mechanic's words.
The rear catalyst is there to clean up the crap that comes out of a modified turbo car because I do have a soft spot for Mother Nature, and because it will outflow the engine until roughly 428hp... Everybody wins.
I've said exactly the same stuff in the PMs I've received from him on the subject. His mechanic thinks I'm a dummy for building it this way, and apparently, his mechanic keeps pushing that with Anthony. This has lead to several PMs asking why I did it like this and that "the system doesn't make any sense")his mechanic's words.
The rear catalyst is there to clean up the crap that comes out of a modified turbo car because I do have a soft spot for Mother Nature, and because it will outflow the engine until roughly 428hp... Everybody wins.
94383Z71
New member
Great post and thread, but I want to expand on this a bit- so we could cut or simply pack up the rear bung and not use it at all. This would leave that bung viable for WBO2 down the road.
Obviously you would still have to deal with the CEL, but that's no different anyways.
If you have a tune, you could just unplug it and remove it entirely from the exh. system. You could in fact use that for a WB.
Using this exact setup right now, the wideband is a tad sloww on idle but every other time it gives good response
ReeseLightning
New member
Correct threads, but I've never used a "J" so I can't say 100% that it will clear everything under there. It should, but hopefully someone using a "J" will chime in.
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