[gT-BMW]

Originally Posted by Rickyshucks

I am having my roundelwerks headers installed on Thursday... quite excited.

I'll be running with the stage 3 manifold, bimmerlabs 330i flash, and headers. Do you think things will run well with that 330i flash or should I look into getting an actual tune?

I have a similar setup except i have a 6spd manual, secondary cat deletes and 3.73 diff. over here in fl on a 2 lane highway when your blocked in by 2 cars doing 45mph in 55mph zone, when you finally get a chance the pass all of a sudden the other car wants to speed up. no offense but this happens alot with canadian drivers. i can easily pass those cars trying to speed up with ease without downshifting.

the greatest thing about the i6 it makes peak torque faster than its v6 counterparts even though they run a faster 1/4 mile. im always having fun when i encounter those a holes lol

[Rickyshucks]

Originally Posted by gT-BMW

I have a similar setup except i have a 6spd manual, secondary cat deletes and 3.73 diff. over here in fl on a 2 lane highway when your blocked in by 2 cars doing 45mph in 55mph zone, when you finally get a chance the pass all of a sudden the other car wants to speed up. no offense but this happens alot with canadian drivers. i can easily pass those cars trying to speed up with ease without downshifting.

the greatest thing about the i6 it makes peak torque faster than its v6 counterparts even though they run a faster 1/4 mile. im always having fun when i encounter those a holes lol

Hah, I can't deny it. Canadian drivers are ass. I live in an area called Brampton... can't get any worse than that.

I've got a 6 speed too and 2ndary cat delete but a stock diff.

[Wally_84]

Originally Posted by hassmaschine

No, this is wrong.

Modern DMEs run on models of the engine - models which assume fixed parameters, like the O2 sensor readings are an average of 3 cylinders per bank, not just one. This makes it cheaper to design and easier for the original calibrators to tune.

With that sensor placement, not only is the sampling rate 1/3 of the expected value, you're assuming that only cylinders #2 and #5 make any difference to the OEM model of the engine. That I can say for certain is false.

I'm not at all saying you should pay AA $800 (or whatever) to order the same thing for you (from China, because who's kidding, everything is unless you're SuperSprint). But sensor placement definitely matters.

Which goes back to my original reply. If you have a "header" tune (which means deleting error codes in the case of AA), just put the primary sensors in the bung after the collector, and plug the first one. No matter who tunes your car, the second sensor isn't doing anything once the cats are removed anyway.

So I did what Hass suggested. I pluged the first bungs on cyl 2 & 5, and moved those o2 sensors to the bungs at the merge. I wanned to test drive but check light came on so I had to check those erros first. I got 2C9E & 2C9F. What would you suggest now? Can I dive like that? Or should I remove those headers and weld extra bungs for post cat o2?

[hassmaschine]

Well you're going to get post cat sensor errors either way. You need a tune.

[Ethan Skinner]

Originally Posted by hassmaschine

Well you're going to get post cat sensor errors either way. You need a tune.

Ok update y'all I've got the Active autoweks tune and I'm running the O2 sensor delete awesome. The 300 dollar headers have perfect fitment and sound amazing. I am not running any of my O2 sensors.

[hassmaschine]

We've already explained why running no O2 sensors is a horrible idea.

[desertman123]

The O2 sensor delete is for THE CHECK ENGINE LIGHT.

It ***DOES NOT*** allow you to unplug your O2 sensors.

[Wally_84]

Originally Posted by Ethan Skinner

Ok update y'all I've got the Active autoweks tune and I'm running the O2 sensor delete awesome. The 300 dollar headers have perfect fitment and sound amazing. I am not running any of my O2 sensors.

Like everyone here have said, you need pre cat 02 sensors for a lot of reasons, you just don't need the post cat ones.

Hass I have BPC Tune from Bob from the time he worked there but i guess he assumed that I have headers from AA like everyone else in US and did not code out post cat sensors. Any one knows if Bob can still do some work via BPC handheld?

[Rmtt]

Originally Posted by Wally_84

Like everyone here have said, you need pre cat 02 sensors for a lot of reasons, you just don't need the post cat ones.

Hass I have BPC Tune from Bob from the time he worked there but i guess he assumed that I have headers from AA like everyone else in US and did not code out post cat sensors. Any one knows if Bob can still do some work via BPC handheld?

Unfortunately no from what I was told. You have to get a new cable from him because the files are locked to the old BPC tune and cable. Then download the software from his website. Basically the same process as before. Upload your file with the new cable and software, and then send in to him for re-work.

I had the 3SI tune, but will be installing my AA headers next week, so he is currently working on my new tune.

[Ethan Skinner]

Got the O2 sensor delete and header/burble tune from active autowerk. Car runs perfect and rips. Pops like crazy love it.

[Wally_84]

To summarize my experience with eBay headers.
I've bought eBay headers similar to those mentioned in first post.
Overall imho quality of those headers is great no problem here.
After install and tune I had lean mixture error code, but car run fine so I thought its o2 related problem (no CEL). It wasn’t and it took me a year to narrow it down to badly positioned header primary o2 bungs (they are on 2 and 5 cyl only). After I plugged primary bungs on 2 and 5 cyl and moved primary o2 sensors to the rear bungs lean mixture error disappeared. Off course it lead to another error caused by unplugged secondary o2 sensors (CEL was present).
At this time it was obvious that headers were responsible and need to be re-worked.
New bungs were welded in and headers with all 4 o2 sensors installed, no errors or any fault codes since.

[BalkanAvenger]

Hi. I have these headers on my car. No problems since day one. They've been on my car for 1.5 years.

I prefer the o2 sensors facing UP. It's much easier to replace them when they go bad. My bank 1 upstream failed on me, changed in about 30 mins. Second one failed later, that swap was easy too. 30 mins of work.

Car is a 2006 325i N52 4-Door, 6-Speed Manual.