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Author Topic: N249 delete  (Read 10507 times)
nautica
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« on: October 12, 2015, 12:56:27 PM »

Hi all. I need help to completly delete N249 from the bin.
Audi S3 BAM engine. I have located maps but not working, maybe i'm wrong. Please somebody help me.

ESKONF     10BF4
CWDLDUV  19978
TMDLDUV  1997D

Here is attached file, thank you.
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vwaudiguy
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« Reply #1 on: October 12, 2015, 07:22:45 PM »

What is your goal with this modification?
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adam-
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« Reply #2 on: October 13, 2015, 12:45:07 AM »

Don't start this patronising "what's your goal for this".  There's already a massive thread about deleting the N249 and why it's "bad", so he can go read that if he wishes. 

http://nefariousmotorsports.com/forum/index.php?action=printpage;topic=3828.0

PRJ sums this up near the end:
Still tons of crap said and not a single scientific explanation posted by the "delete everything" posters.
Just taking lots of things out of context. For the final time, the turbos are not going to explode even if you remove dump valves altogether.

They will just experience more surge. Just as they will experience more surge with removal of N249.
Lending examples from motorsport teams is completely irrelevant, as on a motorsport car the N249 is useless, as that car is driven to very high RPM's all the time where the generated vacuum will instantly open the dump valves anyway. Not to mention motorsport teams really don't give a damn about long term turbo life.
Part throttle issues only exist on cars with messed up tunes - even then, if you feel it intervenes too much for some reason you can easily tune the negative pressure gradient required for the boost to drop.

The N249 is a device that is there to prevent stalling the compressor at low transient loads in a day to day car. It can also function as a safety device in case of wastegate stuck shut.
This:
* Eliminates compressor stall on the turbo at low loads thus extending it's service life
* Prevents air from moving backwards through the intake tract and oil mist building on the MAF.
* Somewhat improves fuel economy by reducing pumping losses.
* Can save you from a grenading turbo and engine damage in case the wastegate actuator becomes stuck for some reason.

On any motorsport car this device is useless because:
* The motorsport car is not driven at low transient loads.
* Because of how little time it spends at low transient loads this is not going to have any measurable effect on the turbo life
* Fuel consumption is completely irrelevant.
* Most likely you are running PCV that is vented to atmosphere or has a catch tank, as without it you will have very high oil consumption, so there is not going to be any oil vapors in the intake air.
* Turbos are not mounted on motor sport cars for 10+ years, so there is almost no chance that the actuator is going to be stuck.

Removal of it makes nothing better, besides saving 300 grams of weight, if that, assuming the torque management of the ME7 ECU is tuned correctly.

To remove the DTC's associated with the N249 valve you will need to:
* Find the relevant bits in ESKONF (on the 1.8T this is the 2nd to last bits in the fourth of the seven bytes) and set them to 11 - that will kill end stage diagnosis and the open circuit code.
* To remove the plausibility diagnosis you can for example FF DLDUVES or TMDLDUV - this worked fine for me on 1.8T
« Last Edit: October 13, 2015, 02:29:25 AM by adam- » Logged
Snow Trooper
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« Reply #3 on: October 13, 2015, 02:04:28 AM »

Bravo adam, bravo! Who cares what and why, this site is for info, nothing more. Maybe he is building a damn racecar.
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justindcady
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« Reply #4 on: October 13, 2015, 07:06:15 AM »

It seems to me that the N249 is an early version of what's currently being done on the newer engines: Direct Actuation of the dump valve.  The only difference is that the 1.8T and 2.7T's ECU communicates to a solenoid to manipulate the vacuum signal to the DV, instead of the ECU communicating to a solenoid that *IS* the DV.

Granted, I'm nothing more than a lurker because I enjoy the knowledge that's shared here, but it seems to me that the advantage of the direct actuation (even in the 'old' N249 method) is to have your DV open because the ECU is able to determine within your lifting of the throttle that you're going to come off of it...thus releasing the pressure a *bit* sooner than waiting for the actual vacuum.  On the new setups not using a vacuum signal at all, I'm sure there's also a benefit to the DV being closed upon increased load being requested, not when a positive pressure signal is received.  There is another thread floating around where a few people have retrofitted a new style DV onto a 1.8T with fairly decent results.
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vwaudiguy
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« Reply #5 on: October 13, 2015, 10:35:53 AM »

Don't start this patronising "what's your goal for this".  There's already a massive thread about deleting the N249 and why it's "bad", so he can go read that if he wishes.  

http://nefariousmotorsports.com/forum/index.php?action=printpage;topic=3828.0

PRJ sums this up near the end:

I asked because merely suggesting he code it out with ESKONF I was looking for what issue he was trying to resolve...I also don't assume everyone on here has read every thread on the topic.
« Last Edit: October 13, 2015, 10:42:14 AM by vwaudiguy » Logged

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nyet
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« Reply #6 on: October 13, 2015, 10:38:42 AM »

Bravo adam, bravo! Who cares what and why, this site is for info, nothing more. Maybe he is building a damn racecar.

While I admire the spirit in which this was posted, experience tells us you are being delusional Smiley

100% of the people who post on an internet forum asking how to delete the N249 have no clue why they are deleting it.

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ME7.1 tuning guide
ECUx Plot
ME7Sum checksum
Trim heatmap tool

Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
adam-
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« Reply #7 on: October 13, 2015, 12:01:30 PM »

While I admire the spirit in which this was posted, experience tells us you are being delusional Smiley

100% of the people who post on an internet forum asking how to delete the N249 have no clue why they are deleting it.

I totally agree with you!  When I first got my 1.8t, I read "The Ultimate SAI, N249... etc" delete, and because it was well-written and every did it, I followed too.  No-one had documented why they were deleting it, just that they experienced smoother part-throttle.

Now I understand the valve and it's purpose, I should have probably kept it.  But, since I prefer the cleaner bay look, it's staying out.  I'm going to kill my turbo with NLS well before I do from compressor stall.

That thread I posted gives excellent understanding as to the valves workings, and the OP can make his own choice from there.
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JustGav
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« Reply #8 on: February 24, 2020, 06:07:11 AM »

Having read the http://nefariousmotorsports.com/forum/index.php?topic=9141.0 thread regarding the good idea / bad idea bits of removing the N249, I've taken the decision to remove it and deal with the issues that occur. Mainly because I simplified the engine bay on the ropey car by removing a lot of the hoses which were perished.

If I find any disastours side effects I will plumb back in an N249, however for now I'm going live with it.

From reading this thread and the the above mentioned ones, the conclusion I've come to is that I need to change

ESKCONF, CWDLDUV and TMDLDUV, is this thinking still correct in 2020? or have the internets found a better way?

Thanks
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JustGav
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« Reply #9 on: February 24, 2020, 07:06:44 AM »

One thing I have noticed, is that I'm now getting the P1297 error code (pressure between throttle...) and it limits the boost. So will need to work out how to prevent this code being thrown
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nyet
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« Reply #10 on: February 24, 2020, 09:45:15 AM »

Plumb in a n249, call it a day.
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ME7.1 tuning guide
ECUx Plot
ME7Sum checksum
Trim heatmap tool

Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
JustGav
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« Reply #11 on: February 24, 2020, 09:54:43 AM »

Pipe work was all perished on my shed, so will need to get a new N249 and pipe work.... Off to buy some bits I guess Tongue
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adam-
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« Reply #12 on: February 24, 2020, 12:02:52 PM »

Or just lift FPDKLDUS.
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nyet
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« Reply #13 on: February 24, 2020, 02:39:15 PM »

Or just lift FPDKLDUS.

not advisable IMO, but we can agree to disagree Smiley
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ME7.1 tuning guide
ECUx Plot
ME7Sum checksum
Trim heatmap tool

Please do not ask me for tunes. I'm here to help people make their own.

Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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