[timothy2001]

At the risk of, well you know, the graphic below.

It's been my experience when an 'out of parameter' condition exists that will set a code for O2 sensors, it often takes time and/or miles after the code is cleared for it to set again. Depends on load etc.

From what I have read, installing a catless DP ensures that is not the case. With a catless DP, the code is a 'hard code' and even with JB4 or Cobb constantly clearing it so the driver does not see it, the code stays. NFW it will pass emissions inspection.

I have seen doohickeys, spacers etc but no fix is out there from what I gather.

My conclusion is get the car inspected prior to installing the DP and that gives a year for 'someone' to come up with a real fix. Removing the DP and re-installing the stock piece ain't gonna happen unless I install a lift and my Mrs. BMW......well I am not gonna even float that one.

Summing up all the posts out there, can someone weigh in if I have it straight? Just ordered my DP.

Thanks

[Jsoboti]

Sounds about right to me

[JETmn]

It sounds like you can get by when using a minicat and driving a short distance nicely to the testing station. Once you get on it, then it will throw a code.

[335m]

If you are really in Houston you can easily find someone in a local car group who will pass you through inspection. Check the Eurotic of Houston facebook group.

[timothy2001]

Originally Posted by 335m

If you are really in Houston you can easily find someone in a local car group who will pass you through inspection. Check the Eurotic of Houston facebook group.

Yep, in Houston and that's great news! Thank you.

[335m]

Originally Posted by timothy2001

Yep, in Houston and that's great news! Thank you.

No problem, happy modding

[wgknestrick]

Originally Posted by timothy2001

At the risk of, well you know, the graphic below.

It's been my experience when an 'out of parameter' condition exists that will set a code for O2 sensors, it often takes time and/or miles after the code is cleared for it to set again. Depends on load etc.

From what I have read, installing a catless DP ensures that is not the case. With a catless DP, the code is a 'hard code' and even with JB4 or Cobb constantly clearing it so the driver does not see it, the code stays. NFW it will pass emissions inspection.

I have seen doohickeys, spacers etc but no fix is out there from what I gather.

My conclusion is get the car inspected prior to installing the DP and that gives a year for 'someone' to come up with a real fix. Removing the DP and re-installing the stock piece ain't gonna happen unless I install a lift and my Mrs. BMW......well I am not gonna even float that one.

Summing up all the posts out there, can someone weigh in if I have it straight? Just ordered my DP.

Thanks

If you can understand my post in the original thread, spacers don't do shit for helping this issue.

We need voltage (waveform) measurements FIRST before we can develop a fix. We need someone with a scopemeter to pull waveforms from a stock car AND from a catless car. Once we have those, we can design a simple electronic fix. These work, but must be tuned to convert the waveform to stock.

The mechanical fixes do not work because they change the response time in the wave form, not the peak Volts. It's not hard, we just need someone with the right equipment to step up. There has to be an EE on here somewhere that has access to a scopemeter.

http://www.amazon.com/HDS1021M-Handh...rds=scopemeter

Originally Posted by wgknestrick

I agree with others that this got off track, and I apologize. If you want to create an intake design thread, I can move the posts in there.

Back on catless CEL track:

Do we have any update on the N55 CEL fix for catless downpipes? I am very skeptical of the solution posted working long term because I know how hard it can be to fool the electronics. We probably need someone with a scope-meter to see the transient voltage the ECU wants to see (and when) from the O2 sensor(s). I would LOVE to find something that works though. It would also help if BMS could help share their past efforts here and why they didn't work. I would guess they spent a good deal developing their N54 solution and just tried that on the E9x N55. It didn't work and they probably scrapped it due to low volume.

The path I see a solution developing is to scope the O2 voltage on a stock car and then compare that transient graph with a catless O2. Once we know the offset, then we can start to develop an electronic solution to shift the V waveform.

for example:


Generally the voltage interceptors work best IMO over the mechanical. The mechanical tend to have too much delay (longer wave periods) in V readings. They don't always shift the waveform (up or down) into the acceptable zone.

[timothy2001]

Originally Posted by wgknestrick

If you can understand my post in the original thread, spacers don't do shit for helping this issue.

We need voltage (waveform) measurements FIRST before we can develop a fix. We need someone with a scopemeter to pull waveforms from a stock car AND from a catless car. Once we have those, we can design a simple electronic fix. These work, but must be tuned to convert the waveform to stock.

The mechanical fixes do not work because they change the response time in the wave form, not the peak Volts. It's not hard, we just need someone with the right equipment to step up. There has to be an EE on here somewhere that has access to a scopemeter.

http://www.amazon.com/HDS1021M-Handh...rds=scopemeter

I completely understand this and it is not rocket science. Hopefully someone has the time and O Scope and can do this.

[stormshadow335]

Guys I just went through this on my 335. I installed catless dp's about a year ago and of course the car generated the check engine light. I recently needed to pass inspection and tried a dp fix which didn't work. After a month of frustration a friend suggested that I install 02 extenders on the secondary 02's. I bought two extenders and since the dp's are tight I had a local exhaust guy bung the 02 inserts on the dp and create two inserts right below the cats on the catback section of the exhaust.

I took the car out that night and drove it hard with no check engine sell. All monitors were ready with the exception of the evap system. Took it to the inspection shop the next day, Tuesday, and passed. I checked the evap status today and that's also now ready and still no code. The extenders cost about $45, plus $200 to relocate the 02 sensors, install the extenders and he may have extended the 02 sensor wires as well. For roughly $250 I think this fix is more than worth it because I was about to go insane trying to complete the drive cycle with hybrids cutting me off and giving me the finger lol. Also totally drove the car normally and achieved readiness within about a half an hour run.

Hope this helps.