Flap or no flap - Does it effect performance ?

[ac427]

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]

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]

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

Broken flap 0-30 bhp less.

[ac427]

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]

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:smt055


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 RT4]

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 :bigcry: ) 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]

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 :bigcry: ) 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











:bigcry::whistle:

[Mike RT4]

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











:bigcry::whistle:

Harsh :bigcry:.

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

[shimmy]

Harsh :bigcry:.

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 2.08)

[cslsuperfan]

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.

[NZ_M3]

Fairly sure the USA guys that have been disassembling the CSL software have discovered a specific VE map related to the flap opening and closing and yes it does affect the tune of the car.

[shimmy]

Fairly sure the USA guys that have been disassembling the CSL software have discovered a specific VE map related to the flap opening and closing and yes it does affect the tune of the car.

are you saying if i put the flap back in, my CSL will go faster?

[alexk]

are you saying if i put the flap back in, my CSL will go faster?

Yes like mine does :blalalala:

[s1csl]

Showing 2 snorkels left with BMW, so if your motor is not working you need to buy

[shimmy]

Showing 2 snorkels left with BMW, so if your motor is not working you need to buy

cost?