Flap or no flap - Does it effect performance ?

ac427 · 12-11-2015, 11:13 AM

Aplolgies if this has been covered before but....

Lots of non CSL owners keeping banging on about the CSL snorkel flap and low down torque.

I know loads of you guys remove the flap because it can be a bit problematic.

Is the flap just for noise reduction or does it actually help low down torque?

Have you guys noticed any real difference with and without the flap?

GregorFuk · 12-11-2015, 01:11 PM

I find my car runs better with the flap on and working. Without it it seems to lack low down torque and I experience the odd bout of jerkiness from the engine. Situations where I'd notice it the most were for example; slowly turning off a junction onto a steep hill in say second gear.

**shimmy** · 12-11-2015, 02:24 PM

Flap on flap off no difference in performance but a bit easier to drive cold

Broken flap 0-30 bhp less.

ac427 · 12-11-2015, 02:41 PM

Quote:

Originally Posted by shimmy

Flap on flap off no difference in performance but a bit easier to drive cold

Broken flap 0-30 bhp less.

Ta Shim, So it's easier to drive when warming up the engine or when the air temp is low ?

select · 12-11-2015, 03:04 PM

It is a little more jerky to drive when its cold.. but i think once its warmed up there is no real difference. But you get a deep growl below 3000RPM when you push the noise pedal... i love it

The flap's main job is to reduce noise emissions.
When you read your DME with tool32, it even is called "Geräuschklappe" which literally translates to "noise flap".

**Mike R** · 12-11-2015, 04:00 PM

It may be called the "noise flap", but I believe it is also used to tune the intake volume to regulate the intake air speed for driveability at low rpm speeds (hence why it is reported that below a certain rpm, flapless (oh er

) it creates hesitations at certain rpms / throttle sweeps as the change in air speed is too great for the ECU to regulate / deal with.

**shimmy** · 12-11-2015, 05:44 PM

Quote:

Originally Posted by Mike R

It may be called the "noise flap", but I believe it is also used to tune the intake volume to regulate the intake air speed for driveability at low rpm speeds (hence why it is reported that below a certain rpm, flapless (oh er

) it creates hesitations at certain rpms / throttle sweeps as the change in air speed is too great for the ECU to regulate / deal with.

I think you are correct......but I only drive mine FLAT OUT so I would never know the hesitation exists.

Looking at your Snett vids, you probably feel the hesitation at a number of points

**Mike R** · 12-11-2015, 05:50 PM

Quote:

Originally Posted by shimmy

I think you are correct......but I only drive mine FLAT OUT so I would never know the hesitation exists.

Looking at your Snett vids, you probably feel the hesitation at a number of points

Harsh

.

I'm sure I could do a 2.09 with a clear track

.

**shimmy** · 12-11-2015, 07:10 PM

Quote:

Originally Posted by Mike R

Harsh

.

I'm sure I could do a 2.09 with a clear track

.

post it up Mike, post it up. (oif its Harrys LAptimer it needs to show 2.0

cslsuperfan · 12-11-2015, 10:15 PM

5 years flapless without any issues

NZ_M3 will know all the techno pro's and con's to running with/without the flap.

drop him a PM.

12-11-2015, 11:13 AM	#1
ac427 S2 - Picking it up Join Date: Feb 2011 Posts: 71 Casino cash: $977	Flap or no flap - Does it effect performance ? Aplolgies if this has been covered before but.... Lots of non CSL owners keeping banging on about the CSL snorkel flap and low down torque. I know loads of you guys remove the flap because it can be a bit problematic. Is the flap just for noise reduction or does it actually help low down torque? Have you guys noticed any real difference with and without the flap?

12-11-2015, 02:24 PM	#3
shimmy CSL Register Uber-poster! Join Date: Apr 2008 Location: Uk Posts: 14,646 Casino cash: $43909	Flap on flap off no difference in performance but a bit easier to drive cold Broken flap 0-30 bhp less. __________________ .

12-11-2015, 03:04 PM	#5
select S5 - Full Throttle Join Date: Oct 2014 Location: Germany Posts: 475 Casino cash: $6813	It is a little more jerky to drive when its cold.. but i think once its warmed up there is no real difference. But you get a deep growl below 3000RPM when you push the noise pedal... i love it The flap's main job is to reduce noise emissions. When you read your DME with tool32, it even is called "Geräuschklappe" which literally translates to "noise flap". __________________ Greetings, Julian.

12-11-2015, 04:00 PM	#6
Mike R S6, Sport On, Traction Off Join Date: Dec 2010 Location: Norwich Posts: 1,585 Casino cash: $17591	It may be called the "noise flap", but I believe it is also used to tune the intake volume to regulate the intake air speed for driveability at low rpm speeds (hence why it is reported that below a certain rpm, flapless (oh er ) it creates hesitations at certain rpms / throttle sweeps as the change in air speed is too great for the ECU to regulate / deal with. __________________ Mike R Sarcasm is just a free service I provide. Nordschleife, there's only two barriers to worry about - the ones on the left and the ones on the right . CSL number 044

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12-11-2015, 01:11 PM	#2
GregorFuk S5 - Full Throttle Join Date: Nov 2014 Posts: 318 Casino cash: $11097	I find my car runs better with the flap on and working. Without it it seems to lack low down torque and I experience the odd bout of jerkiness from the engine. Situations where I'd notice it the most were for example; slowly turning off a junction onto a steep hill in say second gear.

12-11-2015, 10:15 PM	#10
cslsuperfan Driving it like I nicked it Join Date: Apr 2008 Location: wales Posts: 2,222 Casino cash: $19520	5 years flapless without any issues NZ_M3 will know all the techno pro's and con's to running with/without the flap. drop him a PM.