Does it ever stop??....plus de flap?

[patphnx]

No flap in mine either!

:beer:

[GregorFuk]

I think running without a flap does decrease the life span of your air filter. It tends to get dirtier faster. I also worry about driving in hard rain, will it cause the filter to get wet? On that one I have no idea.

It's funny this subject has come up as I am currently flap-less but I have a log drive to LeMans coming up. I was considering reinstating the flap for this journey, what are people's thoughts on this?

[MisterCorn]

I haven't looked at removing the flap, but if it really as easy as you say I might give it a go myself, I don't think driving in the rain will be a big issue.

MC

[alexk]

I think running without a flap does decrease the life span of your air filter. It tends to get dirtier faster. I also worry about driving in hard rain, will it cause the filter to get wet? On that one I have no idea.

Yes rain will likely go inside the intake manifold.
That's another reason of not using the sport button in heavy rain, avoid rain going inside the intake

[select]

I haven't looked at removing the flap, but if it really as easy as you say I might give it a go myself, I don't think driving in the rain will be a big issue.

MC

I removed my flap a couple of weeks after i bought my csl roughly a 1 year ago. I didn't have a single issue since.

Here is how you remove it:
You have to unscrew the flap motor then manually turn the flap open to reveal the 3 hex screws. Remove these and then manouver the flap out of the airbox and then simply screw the flap motor back in.

Btw, does somebody know if removing the flap motor will throw a code? If not i will see what happens when you do, in the next couple of days.

Yes rain will likely go inside the intake manifold.
That's another reason of not using the sport button in heavy rain, avoid rain going inside the intake

I don't think rain will get sucked up as far as the air filter. I think the rain drops will hit the first bend of the plastic tube.
Besides i think if they would manage to reach the filter, BMW would have told people in the manuals.

In my opinion the flap is simply used as a means to comply with noise emission laws.
If i remember correctly its actually called "Geräuschklappe", which translates to "Noise Flap", in the ECU.

[alexk]

Besides i think if they would manage to reach the filter, BMW would have told people in the manuals.

I can think of at least 10 things that are not written in the owner's manual :hahaha:

The flap is definitely for torque boost in low rpms - fact.
It's not just for noise.
This is also due to the fact that the CSL gives you full throttle control, something that doesn't exist anymore (in other words, when you hit full throttle with 1500rpm, the CSL will open the throttle butterflies to 100%).
If you were controlling/restricting the throttle opening, you don't need a flap anymore (bikes had additional throttle butterflies to restrict airflow then newer generation had controlled/restricted throttle control).
I personally love the full throttle control the CSL gives to the driver.

Not removing the flap due to performance and risk of rain is my opinion and what I do when there is heavy or torrential rain.
If you check the intake when driving with heavy rain and 120-140, we can discuss again. The water can go to the intake.
Each one can decide for their own of course, since they own their cars :thumbs:
I mentioned my point of view since someone asked and I just give facts.

[cslsuperfan]

I think running without a flap does decrease the life span of your air filter. It tends to get dirtier faster. I also worry about driving in hard rain, will it cause the filter to get wet? On that one I have no idea.

It's funny this subject has come up as I am currently flap-less but I have a log drive to LeMans coming up. I was considering reinstating the flap for this journey, what are people's thoughts on this?

I don't drive in the rain unless of course it's a euro/long drive and the weather turns against you.

The filter certainly gets dirty quick and that's with the flap in place. Not sure if removing the flap increases the level of dirt but it may increase the volume of air passing into the airbox with sport off.

I've been flapless for 5 years and driven in some heavy rain. (Munich 2013 springs to mind). Never had an issue with water ingress.

[terra]

I thought Sport opened the flap all the time.. Does it just open it earlier then ?

From the software, this is when the flap opens in non-sport and sport modes:

Non-sport:

0000 0001 0002 0003 0004 0005 0006 0007 - Gear
2328 2328 2328 1770 1770 1770 1770 2328 - RPM (Hex)
9000 9000 9000 6000 6000 6000 6000 9000 - RPM (Dec)

Sport:

0000 0001 0002 0003 0004 0005 0006 0007 - Gear
0CE4 0CE4 0CE4 0CE4 0956 0780 0640 0CE4 - RPM (Hex)
3300 3300 3300 3300 2390 1920 1600 3300 - RPM (Dec)

In this context, gear 0 means neutral and 7 means reverse. So in non-sport, the flap doesn't open at all in neutral, 1st, 2nd, or reverse. It opens at 6000 in the rest of the gears

In sport mode, it opens at 3300RPM N, 1, 2, 3, and R. 4, 5, and 6 have progressively lower opening points. For gears 3-6, the opening points corresponds to approximately 40mph or 65 km/h

As you can imagine, it is possible to alter this behavior by adjusting the software. On my own car (not a CSL, but running CSL software), I simply set the opening points to 100 RPM in both modes (so flap is always open, but closes when engine is off). Also, I've found the flap still stays closed while the cat-heating function is running (approximately 2 minutes from a cold start).

[Olive]

This is very interresting ! Thanks terraphantm.
I was wondering why it was so difficult to see if the switch was working well. Now with your RPM value I understand better the behaviour => it works well :beer:

Following a problem with the switch, I ordered a new one and have removed the flap in the awaiting of receiving it. I has been received and repaired it...but I never replaced the flap. It was more than 2 years ago.

Today I do not know if I will put on the flap again. I never using my car under rain and ... it is very easy to clean the filter with a vacuum without flap. I guess it is more clean without flap.

Concerning torque. That is the point. I probably do not need to feel it more but I will may be again one day to see if I can really feel the difference.

[cslsuperfan]

This is very interresting ! Thanks terraphantm.
I was wondering why it was so difficult to see if the switch was working well. Now with your RPM value I understand better the behaviour => it works well :beer:

Following a problem with the switch, I ordered a new one and have removed the flap in the awaiting of receiving it. I has been received and repaired it...but I never replaced the flap. It was more than 2 years ago.

Today I do not know if I will put on the flap again. I never using my car under rain and ... it is very easy to clean the filter with a vacuum without flap. I guess it is more clean without flap.

Concerning torque. That is the point. I probably do not need to feel it more but I will may be again one day to see if I can really feel the difference.

Agreed. My ITG filter was boggin' as a result of going flapless.

Never thought of vacuuming! will give it a go!!

[GregorFuk]

Just to add to this thread. I bought my CSL with the flap in a box in the boot, along with the standard brakes. I ran it for over six months flap-less with no real issue but curiosity got the better of me so I sourced a working motor and reinstated the flap. Having now ran for a few weeks with a working flap I would say that the car is much smoother driving round town and at 'normal' road speeds. Even though I miss the full time noise I plan on leaving the flap in place. If it were just for noise control then I'd whip it back out but the car is obviously happier with it in place.

[Olive]

hum ... difficult to know what I will do ...
I will probably try to reflap duing the summer holiday and try to see if I can really fell a difference of behaviour on low rpm.
It is pity to confirm that flap is never open in std mode on 3 first gears :banghead:

[select]

Well my car came the flap in place and i removed it 2 months after i bought it.
I love that low deep rumble it produces in the low rev range. You don't need to drive it like you stole it all the time.. surely helps me keeping my driving license :hahaha:
Altough it has a tendency to produce reactions from bystanders, both positive and negative :hahaha:

Plus you don't have to use the sport button all the time which is way too twitchy imho.

Although i liked that moment when all of a sudden the flap opens and all hell breaks loose :thumbs:

@terra can you shed some insight into the exact function of the sport button?
As i understood it only changes gas pedal sensitivity at least on the normal m3.

Thanks and sorry for my essay.. i am a bit bored at the party, can you tell? :hahaha:

Julian

[Olive]

@terra can you shed some insight into the exact function of the sport button?
As i understood it only changes gas pedal sensitivity at least on the normal m3.

Hello Julian, the last time I connected my ISTA I was looking for an update of the SMG2 and I was reading some lines concerning the "sport button". It seems that not only the gas pedal sensitivity is modify, but also the gearbox reaction. Honestly I have some big doubts about that...
I will make a print screen next time to show it. I need to investigate further on that topic.

[select]

Hi Olive,


Thats interesting, never heard that before albeit i've read dozens of threads about the functionality of the sport button. From what i gathered is, that, at least in the normal e46 m3 it just changes the throttle sensitivity from linear to a more "fake" mapping. e.g. when you push the throttle 50% the butterfly valves are actually open at 70%. (i made those numbers up, but you get the point)

Would be great if someone can shed some insight in what the sport button on the csl actually does.