If you have aftemarket AA Headers..Please stop in

[carscatscoffee15]

Originally Posted by markslc1

Just installed the AA headers and am about ready to load the AA tune. Fingers crossed that I won't have worse idling issues than prior. Sometimes the car would die at a stoplight when the ac was on

Which tune revision should I be using for n52?

unless you can get to AA and get it on their dyno, I wouldn't go with their OFS tune

[markslc1]

Originally Posted by carscatscoffee15

unless you can get to AA and get it on their dyno, I wouldn't go with their OFS tune

Originally Posted by carscatscoffee15

unless you can get to AA and get it on their dyno, I wouldn't go with their OFS tune

The good news is that the revised tune seemed to do the job for me. The car runs great!

[wolfe]

1. N51 or N52 Engine?
N52

2. Exhaust setup from headers back...eg (Secondary Cats, no Secondary Cats, etc) ?
Secondary cats, BMW PE, flap vacuum line plugged

3. Who is your tune from?
BPC

4. How long have you had them installed?
~3 years

5. Do you still have an idle issue, or did you finally get it resolved?

The idle does still pulse a little sometimes, within about +/-50rpm. Barely noticeable with the A/C on. BPC said if I wanted they could raise the idle a little (which I expect would solve it since A/C on does the same thing). It's so slight that I never bothered to do that.

I have the P3 gauges vent gauge and as the idle is pulsing I see the AFR fluctuating slightly with each pulse.

[Majestic128i]

I am strongly considering getting these headers along with the StageFP tune. How bad is this issue? Is it worth dealing with in a daily driver? Once in a blue moon, at a red light or stop, my idle might drop and stumble for a second or two and be fine right after so I'm also worried doing this would just make it much worse. I also have an n51.

[xshadowspy]

Originally Posted by Rmtt

I am just trying to gather some information as I am frequently seeing these posts. So if you have AA Catless headers installed on your car, would you please answer as best as you can. This is about the "Idle Stumble" issue.

Thanks.

Do you have an idle issue after installation?
If so:

1. N51 or N52 Engine?

2. Exhaust setup from headers back...eg (Secondary Cats, no Secondary Cats, etc) ?

3. Who is your tune from?

4. How long have you had them installed?

5. Do you still have an idle issue, or did you finally get it resolved?

What did you end up doing if you did get it resolved.

I know all of this is vague, but just trying to gather some information on why some people could be seeing this issue, and why some are not. You know how the internet works, most of the people with the problems will let you know, but others with no issues typically don't post about it unless they are posting about their gains!

Thanks guys!

N51 engine

AA headers secondary cat deletes resonator delete 3inch piping and a vibrant Muffler

Custom tuned with AA

2 months

I only ever had idle issues when I had to reflash my car Everytime I got a update from my dataloging for E40 fuel. The car sounded like it would want to die I even have videos of these weird idles but they always went away after 50miles or so of driving so I'm saying in my theory is it just takes time for the car to relearn the new tune and requires throwing on some miles.

[onefastredsc]

Originally Posted by Rmtt

I am just trying to gather some information as I am frequently seeing these posts. So if you have AA Catless headers installed on your car, would you please answer as best as you can. This is about the "Idle Stumble" issue.

Thanks.

Do you have an idle issue after installation?
If so:

1. N51 or N52 Engine?

2. Exhaust setup from headers back...eg (Secondary Cats, no Secondary Cats, etc) ?

3. Who is your tune from?

4. How long have you had them installed?

5. Do you still have an idle issue, or did you finally get it resolved?

What did you end up doing if you did get it resolved.

I know all of this is vague, but just trying to gather some information on why some people could be seeing this issue, and why some are not. You know how the internet works, most of the people with the problems will let you know, but others with no issues typically don't post about it unless they are posting about their gains!

Thanks guys!

1) N52

2) AA Headers, completely stock exhaust otherwise.

3) StageFP

4) Roughly 1 month

5) No idle issues

The car initially had the fluctuating idle issue after header install on the stock tune. It also initially had the fluctuating idle issue after applying the StageFP flash. But after ~20 miles of highway driving post flash it cleared up and started to idle normally. It has now been approximately 200 miles total since the flash and i still don't have any idle issues.

[Rmtt]

Just to update my experience. N52 and never had any issues after the tune from the headers. Since then I have also done Milvs, re-tune, and still no issues.

All tunes from Bob. The car runs smooth as silk.

[smeard]

Originally Posted by Rmtt

I am just trying to gather some information as I am frequently seeing these posts. So if you have AA Catless headers installed on your car, would you please answer as best as you can. This is about the "Idle Stumble" issue.

Thanks.

Do you have an idle issue after installation?
If so:

1. N51 or N52 Engine?

2. Exhaust setup from headers back...eg (Secondary Cats, no Secondary Cats, etc) ?

3. Who is your tune from?

4. How long have you had them installed?

5. Do you still have an idle issue, or did you finally get it resolved?

What did you end up doing if you did get it resolved.

I know all of this is vague, but just trying to gather some information on why some people could be seeing this issue, and why some are not. You know how the internet works, most of the people with the problems will let you know, but others with no issues typically don't post about it unless they are posting about their gains!

Thanks guys!

Figured i'd give my budget experience a go:

1. N51

2. Full straight pipe, no cats muff or res (obnoxious)

3. Never got the chance to tune it

4. eBay headers were on til car was totaled

5. Never had an idle issue other than cold start and revs dropping back to normal was sometimes exaggerated

[Blau]

has anyone run the headers on their n51 w/o a tune?

[Bimmer-Bob]

Man, I haven't posted on these boards in forever, but just wandered in and this thread caught my eye. Anyway, figured I'd add my $0.02.

Do you have an idle issue after installation?

Yes! Not all the time. Was worst immediately after header install but before flashing software. Improved with first flash and subsequent updates, but not entirely eliminated. I notice some idle hunting at stoplights. I've gotten really used to it, so it's hard to say how often it occurs - probably daily, but it's not super dramatic. Pretty annoying if I think about it, though.

1. N51 or N52 Engine?

N52

2. Exhaust setup from headers back...eg (Secondary Cats, no Secondary Cats, etc) ?

BMW Performance intake --> DISA 3-stage intake manifold --> engine --> Active Autowerke catless headers --> OE secondary headers --> Magnaflow cat-back exhaust.

3. Who is your tune from?

Active Autowerke. I don't even know what version. I feel like there must be an update since I last checked a couple of years ago, but last time I tried to load the software it said it was out of date and I couldn't find a new version. Will try to remember to take another look this week.

4. How long have you had them installed?

I think since 2016?

5. Do you still have an idle issue, or did you finally get it resolved?

Still there. Improved, but not resolved.

Anyway, I don't know what else I can try. It did seem to get a little worse 2 or 3 years ago, right before I replaced the eccentric shaft sensor. I've considered just replacing the VANOS solenoids for the heck of it, since I read somewhere that might help, but last time I checked error codes everything was fine and I'm not inclined to just start spending money on replacing random parts.

[Rmtt]

Originally Posted by Bimmer-Bob

Man, I haven't posted on these boards in forever, but just wandered in and this thread caught my eye. Anyway, figured I'd add my $0.02.

Do you have an idle issue after installation?

Yes! Not all the time. Was worst immediately after header install but before flashing software. Improved with first flash and subsequent updates, but not entirely eliminated. I notice some idle hunting at stoplights. I've gotten really used to it, so it's hard to say how often it occurs - probably daily, but it's not super dramatic. Pretty annoying if I think about it, though.

1. N51 or N52 Engine?

N52

2. Exhaust setup from headers back...eg (Secondary Cats, no Secondary Cats, etc) ?

BMW Performance intake --> DISA 3-stage intake manifold --> engine --> Active Autowerke catless headers --> OE secondary headers --> Magnaflow cat-back exhaust.

3. Who is your tune from?

Active Autowerke. I don't even know what version. I feel like there must be an update since I last checked a couple of years ago, but last time I tried to load the software it said it was out of date and I couldn't find a new version. Will try to remember to take another look this week.

4. How long have you had them installed?

I think since 2016?

5. Do you still have an idle issue, or did you finally get it resolved?

Still there. Improved, but not resolved.

Anyway, I don't know what else I can try. It did seem to get a little worse 2 or 3 years ago, right before I replaced the eccentric shaft sensor. I've considered just replacing the VANOS solenoids for the heck of it, since I read somewhere that might help, but last time I checked error codes everything was fine and I'm not inclined to just start spending money on replacing random parts.

We have the same exact build....exhast and all. The only difference is I have a tune from Bob....and installed MILVS about 3 months back.

But after the header tune.....no issues.....then retune for MILVS.....and still runs smooth as silk.

But the exhaust setup sounds sweet doesn't it?

[Bimmer-Bob]

Originally Posted by Rmtt

We have the same exact build....exhast and all. The only difference is I have a tune from Bob....and installed MILVS about 3 months back.

But after the header tune.....no issues.....then retune for MILVS.....and still runs smooth as silk.

But the exhaust setup sounds sweet doesn't it?

It is a sweet sounding exhaust!

So it's sounding like the idle issues might be an AA thing...

[Rmtt]

Originally Posted by Bimmer-Bob

It is a sweet sounding exhaust!

So it's sounding like the idle issues might be an AA thing...

From what I've seen and read....it does seem to be the tune. I have only read of 1-2 people that still had idle issues after a tune from Bob....abd even then it was very minor.

[Rmtt]

Originally Posted by WeShallCallHerBlau

has anyone run the headers on their n51 w/o a tune?

I have never heard of anyone doing that. Without a tune, you are leaving most of the gains you would see on the table. And headers can be a PITA to install.

I did mine...and after getting through that I wouldn't bother if I wasn't ready to tune afterwards.

Also there is no telling how it would affect everyday driving.

[Blau]

Originally Posted by Rmtt

I have never heard of anyone doing that. Without a tune, you are leaving most of the gains you would see on the table. And headers can be a PITA to install.

I did mine...and after getting through that I wouldn't bother if I wasn't ready to tune afterwards.

Also there is no telling how it would affect everyday driving.

Thanks for the responses man. I'm still on the fence on the headers. Thinking that the risk of idle issues isn't worth it.

[lucaspm98]

Originally Posted by WeShallCallHerBlau

Thanks for the responses man. I'm still on the fence on the headers. Thinking that the risk of idle issues isn't worth it.

I just got headers and MILVs installed plus a tune on my N51 128i from Bob at StageFP a few days ago. He warned me I could have a rough idle for a tank of two of gas as the car relearns. I definitely noticed it, but after two hours of driving it seems to be gone. I’d go for it if I was you.

[Rmtt]

I've mentioned before, but I've had 3 tunes from Bob....all spot on from the start.

He's a great guy....I have talked with a few times on the phone.

[Rmtt]

Originally Posted by lucaspm98

I just got headers and MILVs installed plus a tune on my N51 128i from Bob at StageFP a few days ago. He warned me I could have a rough idle for a tank of two of gas as the car relearns. I definitely noticed it, but after two hours of driving it seems to be gone. I’d go for it if I was you.

I bet that was a nice difference. I did mine incrementally, and although I could definitely tell a difference each time.....I bet combining them was a blast.

[lucaspm98]

Originally Posted by Rmtt

I bet that was a nice difference. I did mine incrementally, and although I could definitely tell a difference each time.....I bet combining them was a blast.

I figured I would get it all done at once so I could get a dyno tune while I was there. Picked up 25 wheel horse power which is a massive difference on a car like this!

[spidertri]

Originally Posted by spidertri

I purchased Rowsdower's car back in July 2019. The car still has the headers and BPC tune installed. Only "power" change I've made is adding a Euro airbox.

I did two things which I believe helped seriously calm down the idle issue on this car. It is still present but it doesn't fluctuate as often or as much as it did.

1) The car stalled at a stop light one day and threw a shadow code for the small DISA. When I swapped it out the DISA flap was stuck in a 30 deg position and did not move at all. When actuated through INPA, the motor would spin but the flap was stuck.

2) I installed a set of Eldor coils (p/n 12138657273) they aren't listed as compatible with the N51/N52 yet but they install and work great in my car. Prior to this, I checked the coils that were in the car and they were the unmarked Delphi coils that others have reported to cause weird electrical issues.

My next step, will most likely be to pull the large DISA and see if it is operating correctly. I probably should have done that by now but the car has been behaving so I kind of forgot about the idle bounce.

I will say that the only time the car idle bounces now, is when I clutch-in roll to a stop. Even then it's not every time. It probably happens the most when going at slow speed in a parking lot and rolling into a spot.

Update to my car's idle issue. I've been driving my normal commute for the past two weeks and it hasn't been bouncing at all at the stop lights where it was most likely to before. If anything, it does a single weird dip like it wants to bounce but then stops itself from bouncing.

The only changes I made were updating the DME using WinKFP and then flashing a stage FP tune over the new DME software. The car previously had BPC tune but I really attribute the idle fix to the DME update.

[OneBigDougie]

Originally Posted by desertman123

Nope, only before I got my tune.


N52


AA headers and muffler delete. Still retain secondaries


BimmerLabs, custom made


According to my maintenance log, almost a year (since April 2018)


Resolved once I switched from a 3-stage only tune to a custom tune to account for the headers



Custom tune

Data point because I don't have issues. Not bragging, but helps narrow down the subset of people with issues. Seems this is an N51 problem.

I have a muffler delete and am inquiring about doing catless headers. I got it tuned 2 days ago and tuned the O2 sensor out thinking I’d do the headers down the road. My question is will it be too loud? I love the way the muffler delete sounds but I’m looking to get the performance benefits of the AA headers. Trying to not sound raspy or tinny.

[Rmtt]

Originally Posted by OneBigDougie

I have a muffler delete and am inquiring about doing catless headers. I got it tuned 2 days ago and tuned the O2 sensor out thinking I’d do the headers down the road. My question is will it be too loud? I love the way the muffler delete sounds but I’m looking to get the performance benefits of the AA headers. Trying to not sound raspy or tinny.

My opinion.....you will want to get a muffler back on. It will be loud. You can always try it out first...but I had a muffler delete and ended up going with a MagnaFlow catback system.

It has a different resonator than stock, and of course the muffler.

But it sounds awesome now!