Swirl Flaps delete

dang2407 · 02-17-2021, 02:23 AM

A lot of people have done the swirl flaps delete, including me. My motivation at the time for doing it was the fact that the gaskets were leaking, and also making things simpler is always attractive. I certainly don't believe there was any performance gain.

But now I see people talking about whether it is a good idea:
1) Part-load combustion and hence soot is affected which affects the DPF.
2) I see on ISTA that there is a check on the swirl flaps relevant to DPF performance.

OK, if you're deleted then you dont need to worry but for the rest of us where it isn't a viable option - is there a downside to the flap-delete?

I've had my X5 nearly a year and after the swirl-flap delete, I started having DPF clogging issues. I dont know if it is coincidence - like I say, I didn't have the car long enough to establish a base-line....

Just wondering what other people's experiences are...

RL18 · 02-17-2021, 06:54 AM

I have both the swirl flaps and egr deleted, not tuned or deleted, and my dpf still regens just fine like before. I've probably put on 20k like this. If your having issue regening you might want to look elsewhere to fix the issue...

Is your coolant temp reaching 180f?
Are your vacuum lines still stock?
Pressure converters and EUVs stock?
Any engine codes?

The swirl flaps if anything will take away some lowend torque, and you might get some more top end due to better flow. But the loss/gain is barley unnoticeable. And if you left the motor installed and plugged in the car has no idea they're missing.

sunny_j · 02-17-2021, 11:29 AM

i personally would not delete swirl flaps on a stock motor for exactly what you mentioned. My friend noticed increased regens after deleting the swirl flaps on a stock motor.

POBEP · 02-20-2021, 01:35 AM

I deleted flaps at 30K.
86K as of today (56K since delete):
- no seal leak of any kind
- no DPF regen issues (I replaced tstat though)
- no noticeable power output change
- no noticeable fuel consumption change.
- no issue with passing inspection

Both NOx sensor's failed (75K), followed by failed SCR cat(79K).
(I still think it has nothing todo with flap delete)

02-17-2021, 02:23 AM	#1
dang2407 Private 9 Rep 60 Posts Drives: 2010 BMW X5 E70 35D MSport Join Date: Dec 2020 Location: France iTrader: (0)	Swirl Flaps delete - retrospective A lot of people have done the swirl flaps delete, including me. My motivation at the time for doing it was the fact that the gaskets were leaking, and also making things simpler is always attractive. I certainly don't believe there was any performance gain. But now I see people talking about whether it is a good idea: 1) Part-load combustion and hence soot is affected which affects the DPF. 2) I see on ISTA that there is a check on the swirl flaps relevant to DPF performance. OK, if you're deleted then you dont need to worry but for the rest of us where it isn't a viable option - is there a downside to the flap-delete? I've had my X5 nearly a year and after the swirl-flap delete, I started having DPF clogging issues. I dont know if it is coincidence - like I say, I didn't have the car long enough to establish a base-line.... Just wondering what other people's experiences are...
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02-17-2021, 06:54 AM	#2
RL18 Major 274 Rep 1,054 Posts Drives: 2011 335d sport Join Date: Nov 2017 Location: Maine iTrader: (0)	I have both the swirl flaps and egr deleted, not tuned or deleted, and my dpf still regens just fine like before. I've probably put on 20k like this. If your having issue regening you might want to look elsewhere to fix the issue... Is your coolant temp reaching 180f? Are your vacuum lines still stock? Pressure converters and EUVs stock? Any engine codes? The swirl flaps if anything will take away some lowend torque, and you might get some more top end due to better flow. But the loss/gain is barley unnoticeable. And if you left the motor installed and plugged in the car has no idea they're missing. __________________ 2011 335d tuned by B.R.R. 2011 X5 35d tuned by B.R.R.
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02-17-2021, 11:29 AM	#3
sunny_j Lieutenant 211 Rep 433 Posts Drives: 2012 X5d Join Date: May 2012 Location: Vancouver, British Columbia iTrader: (0)	i personally would not delete swirl flaps on a stock motor for exactly what you mentioned. My friend noticed increased regens after deleting the swirl flaps on a stock motor. __________________ 2012 X5d \| Deleted & BRR Tuned \| DWR TCU Tune \| 10.25" Android 8.1 Screen Build Thread https://www.xbimmers.com/forums/show....php?t=1529213
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02-20-2021, 01:35 AM	#4
POBEP Lieutenant 366 Rep 553 Posts Drives: E70 E90 E91 Join Date: Mar 2016 Location: Christmas Valley, CA iTrader: (0) Garage List 2011 E90 335d [9.33] 2013 E70 xDrive35d [5.00] 2009 E91 328i [10.00] 2016 F25 xDrive28d [0.00]	I deleted flaps at 30K. 86K as of today (56K since delete): - no seal leak of any kind - no DPF regen issues (I replaced tstat though) - no noticeable power output change - no noticeable fuel consumption change. - no issue with passing inspection Both NOx sensor's failed (75K), followed by failed SCR cat(79K). (I still think it has nothing todo with flap delete)
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