[tke344]

I was doing some research on the topic and obviously the n55 is difficult when it comes to a catless downpipe and obdII readiness. We all know the tunes will clear the codes but for those of us who need to actually pass emissions inspection that won't work.

I found this http://www.o2simulator.com/2013-c-79...tes-p-219.html
device that actually gets spliced in between the upstream and downstream o2 sensors altering the signal between the two. The directions I linked are for a 2013 M6 but it seems the only difference is that motor has 2 pairs of sensors. Wiring should be the same, in both cases it's Bosch o2 sensors. They don't give too many details on the site but I'm guessing this simulator doesn't put out a static voltage but actually takes the input and adjusts it, then outputs to the vehicle side of the downstream sensor.

I currently don't have a catless downpipe but I've never seen anyone mention this option.. If it actually works on an 2013 M6 I imagine it would work on the N55.

From their "functionality" page:

We performed data logging various cars and obtaining information from manufactures on how the catalytic converter intrusive tests are performed and graded. We spent number of years building various prototypes and trying different approaches. Our goal was not to create O2 simulator for a specific car but build a device with mathematical model of the catalytic converter, so it can be applied to any car. So what we built is Smart O2 simulator which should be called “Catalytic Converter Simulator” since it takes signal from the upstream oxygen sensor and figures out what would the downstream oxygen sensor output should be if the catalytic converter would be present.

Our new generation Smart O2 simulator works on virtually all car models. It can take input from Zirconia, Tatania, Ratio and 5/6 wires wideband sensors covering all the types used by car manufactures.

Smart O2 simulator connects between one upstream and one downstream sensor. Cars with two downstream oxygen sensors would require two O2 simulators. Besides connecting two wires to upstream and two wires to downstream sensors, separate connection would need to be made to power (ground and +12v source).

O2 simulator has monitoring LEDs for inbound signal from upstream oxygen sensor and output signal for downstream sensor. Monitoring upstream oxygen sensor LEDs helps to quickly troubleshoot connection to the sensor, making sure connections is properly done and sensor type is correctly set.

[divisionbell77]

You can pretty much bank on it not working for the N55.

[Sidewinderpb]

Well that would be amazing if it worked

[Subaru335i]

Originally Posted by divisionbell77

You can pretty much bank on it not working for the N55.

Why do you say that? Seems plausible.

[tke344]

The logic is definitely there, take the input, modify it according to what an actual catalytic converter would do to the exhaust gases and send it to the ECU side of the downstream sensor. I don't think o2 sensors are as magical as people make them out to be, wideband is more difficult to fool because the voltage range is larger and thus more precise. Mini cat spacers could potentially work but they'd need to allow just the right amount of flow to hit that expected value, anything outside what appears to be a very small range will throw a code.

Like I said, I don't have a downpipe yet, waiting until after the winter when my original warranty is up. I hope someone gives this a try, the instructions seem very simple, it'll take longer to pull the covers to actually get to the o2 sensor plugs. What's nice is the fact that you don't even modify anything on the vehicle's wiring harness, just the o2 sensor wires themselves.

[divisionbell77]

Originally Posted by Subaru335i

Why do you say that? Seems plausible.

Completely different engine and ECU.

If you could just grab an O2 fix from any other engine, we would all have one for our N55's.

[nyfg56]

Anyone ever try this?

[Dark_Knight_335]

I don't know about anybody else on here, but I would actually want to know when my O2 sensors are going bad.

Just the fact that none of our cars play nice with downpipes pretty much keeps me away from them altogether.

[Johnny Boost]

Originally Posted by Dark_Knight_335

I don't know about anybody else on here, but I would actually want to know when my O2 sensors are going bad.

Just the fact that none of our cars play nice with downpipes pretty much keeps me away from them altogether.

Care to elaborate? My car runs just fine with a downpipe and I'm sure I'm not alone. The only problem is that the DP fixes don't work. But then again I don't need a DP fix.

[Dark_Knight_335]

Driving around with a CEL just isn't for me- and any hack that will satisfy the system and not let me know if and when my O2 sensors are truly going bad just doesn't make sense for me Johnny...besides there's no fix for Dinan.

Doesn't a CEL get thrown with DPs out of the box? I notice you have a 2011 like me- is there a chance I might not have an issue?

[Johnny Boost]

Originally Posted by Dark_Knight_335

Driving around with a CEL just isn't for me- and any hack that will satisfy the system and not let me know if and when my O2 sensors are truly going bad just doesn't make sense for me Johnny...besides there's no fix for Dinan.

Doesn't a CEL get thrown with DPs out of the box? I notice you have a 2011 like me- is there a chance I might not have an issue?

After a certain amount of miles, yes the CEL will come on if you don't have a JB4 or Cobb. I wasn't sure what you meant by not playing nice. I think for your set up, high flow catted down pipes would be the best bet.

[Dark_Knight_335]

Originally Posted by Johnny Boost

After a certain amount of miles, yes the CEL will come on if you don't have a JB4 or Cobb. I wasn't sure what you meant by not playing nice. I think for your set up, high flow catted down pipes would be the best bet.

Thanks JB! But the gains won't be nearly as much, is that true? Thanks again bud- hope you had a great Thanksgiving.

[Johnny Boost]

Originally Posted by Dark_Knight_335

Thanks JB! But the gains won't be nearly as much, is that true? Thanks again bud- hope you had a great Thanksgiving.

Happy Thanksgiving to you too. A catted downpipe would add about 10 whp/15wtq with no tune. So with your set up probably 10-15 whp/15-20wtq. It would be a noticeable gain in power.

[nyfg56]

The codes can be cleared with a jb4 or Cobb. The problem that is that even though the code is gone it will still fail emissions and I believe we need them in NY?

[Jsoboti]

Originally Posted by nyfg56

The codes can be cleared with a jb4 or Cobb. The problem that is that even though the code is gone it will still fail emissions and I believe we need them in NY?

Once the tune clears the code the car thinks all is fine... Until you floor it and and enough pressure builds that the non-scrubbed air passes into the mini cat spacer (that you should add to the downstream 02 sensor) and it gets a full breath of the dirty air. If you clear the code, disable the JB4 (map0 for OBDII pass through), and drive like a grandma to the test center, you will pass the OBDII tests.

Someone on here just posted that it worked for them and they passed.

[tke344]

Originally Posted by Jsoboti

Once the tune clears the code the car thinks all is fine... Until you floor it and and enough pressure builds that the non-scrubbed air passes into the mini cat spacer (that you should add to the downstream 02 sensor) and it gets a full breath of the dirty air. If you clear the code, disable the JB4 (map0 for OBDII pass through), and drive like a grandma to the test center, you will pass the OBDII tests.

Someone on here just posted that it worked for them and they passed.

This is what I plan to do basically, and I'm still curious what the Cobb does with regards to clearing the "downpipe" code.. In NY we're allowed one monitor in the "not ready" state, which is what should show for the catalyst efficiency monitor when allowing Cobb to clear the code. I dont' expect any others to be effected. In theory it should pass fine, so long as all of the other monitors go to a ready state.