stupid question: what does this flap do?

andy · 08-25-2006, 05:14 AM

hi all, sorry if this has been discussed before, i searched for "flap" but couldn't find anything that refers to this particular one. it's located under the car, in front of the wheels. i've always assumed it's some kind of mud guard, but shouldn't mud guards be placed behind the wheels? is it there to protect your car from spashes of mud when you go in reverse really fast?

i'm going nuts trying to figure it out

if there has been a previous thread about it please do post the link.
thanks!

Stronie · 08-25-2006, 05:17 AM

No Idea, I've wondered that myself, I've got clumps of grass stuck there riding in the country.

Dante · 08-25-2006, 05:56 AM

1. Aerodynamic purposes.

2. Prevents saltwater from getting onto the brakediscs in wintertime.

Josh49 · 08-25-2006, 06:10 AM

Aerodynamics

330m · 08-25-2006, 06:12 AM

Many cars have these, probably as Dante says to break up air flow before it hits the rear tyre / suspension parts.

txusa03 · 08-25-2006, 06:48 AM

Quote:

Originally Posted by Josh49

Aerodynamics

my guess as well...

Josh49 · 08-25-2006, 06:50 AM

Quote:

Originally Posted by txusa03

my guess as well...

I'm not guessing.

txusa03 · 08-25-2006, 07:20 AM

Quote:

Originally Posted by Josh49

I'm not guessing.

never mind then

Gitta · 08-25-2006, 07:25 AM

If you look underneath there is another set of air dams in farther too.

larsssss · 08-25-2006, 09:04 AM

Cool. I was wondering the same thing.

pauly1 · 08-25-2006, 09:17 AM

The flap is known as a kickdown. As a tire rotates it creates what's know as aero turbulence, the flap helps deflect air around the turbulent wheel and wheelwell. Hence, reducing drag on the car, which helps with performance and fuel consumption.

txusa03 · 08-25-2006, 11:18 AM

Quote:

Originally Posted by pauly1

The flap is known as a kickdown. As a tire rotates it creates what's know as aero turbulence, the flap helps deflect air around the turbulent wheel and wheelwell. Hence, reducing drag on the car, which helps with performance and fuel consumption.

cool...I was going to take them off (reduce weight)

SoYank · 08-25-2006, 11:30 AM

Airbrakes.

obLu · 08-25-2006, 11:32 AM

OT - Andy, those 18" or 19" CSLs?

Asiann · 08-25-2006, 11:32 AM

I thought they were like curb alerts or something since they make this aweful noise when you get too close.

andy · 08-25-2006, 02:09 PM

Quote:

Originally Posted by obLu

OT - Andy, those 18" or 19" CSLs?

19" CSLs

Golfguyjax · 08-25-2006, 03:42 PM

Quote:

Originally Posted by txusa03

cool...I was going to take them off (reduce weight)

How much could they possibly weigh? You may as well empty out your spare change instead.

ImUrGoDaK · 08-25-2006, 03:57 PM

the flapgs reduce the airdrag created by the tires... says my mechanical enignering friend haha only works at high speeds... its probably not doing anything in the states

davide · 08-25-2006, 04:36 PM

Quote:

Originally Posted by ImUrGoDaK

the flapgs reduce the airdrag created by the tires... says my mechanical enignering friend haha only works at high speeds... its probably not doing anything in the states

exactly!!

just4kickz · 08-25-2006, 05:31 PM

LOL i scratched my front ones the first day i got it... was still getting used to the length of my car while parking... geez lols

CnoteMD · 08-25-2006, 06:25 PM

I am very glad that those flaps are there!!! About 2 months after buying my car, I saw a 8-10 inch piece of metal hanging off of one of those flaps (it was like a long metal wire, but about as thick as a coffee stirring straw). I took it too the dealer to see if something had broken off of my car.

When they got down there, they saw that it was something from the road that actually punctured through the flap and ended up "attached" to my car. They simply pulled it out and threw it away.

If it wasn't for that flap, it would have gone straight to my expensive and hard to find rear runflat tire!

gr8sho · 08-26-2006, 01:47 PM

Quote:

Originally Posted by pauly1

The flap is known as a kickdown. As a tire rotates it creates what's know as aero turbulence, the flap helps deflect air around the turbulent wheel and wheelwell. Hence, reducing drag on the car, which helps with performance and fuel consumption.

Never mind the flaps, gimme those awesome tusks BMW was running on their F1 cars!!!

BTW, in case you missed it, BMW pipped Mercedes in qualifying today at the Turkish GP.

08-25-2006, 05:14 AM	#1
andy Sabaku SouSou 5 Rep 171 Posts Drives: Arctic E90 320i Join Date: May 2005 Location: Manila iTrader: (0) Garage List 2005 320i [0.00] 2006 Toyota Hi Lux [0.00] 2006 Ford Focus Mk2 ... [0.00]	stupid question: what does this flap do? hi all, sorry if this has been discussed before, i searched for "flap" but couldn't find anything that refers to this particular one. it's located under the car, in front of the wheels. i've always assumed it's some kind of mud guard, but shouldn't mud guards be placed behind the wheels? is it there to protect your car from spashes of mud when you go in reverse really fast? i'm going nuts trying to figure it out if there has been a previous thread about it please do post the link. thanks! Attached Images __________________ andy Arctic 320i: Black Dakota Leather, Silver Trim MODS: OEM rear deck spoiler, chrome exhaust tip, window trim and grille, 8.5 x 19 CSL reps all around, Dunlop Le Mans 245/35/R19s, 10mm H&R spacers rear, OEM style front splitters, Bi-Xenons
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08-25-2006, 05:17 AM	#2
Stronie Major 314 Rep 1,453 Posts Drives: 2017 F80M3 Comp. 6MT Join Date: May 2006 Location: Instagram: @Atlantis_S55 iTrader: (0)	No Idea, I've wondered that myself, I've got clumps of grass stuck there riding in the country. Last edited by Stronie; 08-25-2006 at 06:02 AM..
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08-25-2006, 05:56 AM	#3
Dante Enthusiast 468 Rep 1,791 Posts Drives: F87 M2 / F31 330d Join Date: Nov 2005 Location: Bavaria iTrader: (0) Garage List 2004 E46 BMW M3 [0.00] 2017 F87 BMW M2 [10.00] 2013 F31 330d Touring [9.50] 2009 E89 Z4 Sdrive 30i [9.00] 1989 E30 320is 2-door [10.00] 1986 E28 M535i [9.00]	1. Aerodynamic purposes. 2. Prevents saltwater from getting onto the brakediscs in wintertime.
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08-25-2006, 06:10 AM	#4
Josh49 Major General 252 Rep 6,664 Posts Drives: E90 325xi Join Date: Jan 2006 Location: Boston, MA iTrader: (33)	Aerodynamics __________________ E90 325XI, MYSTIC BLUE ON BLACK/ALUM, STEP, NAV, PDC, CWP, XENON, SIRIUS, ALARM, MUD GUARDS, CLEARBRA, CHROME GRILLS AND TIPS, VALENTINE 1 (HARDWIRED), HO CERAMIC 40%, 161'S, REAR FOG MOD, LUX 4.0, BLACKLINES, OEM PEDALS, MTEC FOGS, GRUPPE-M REP INTAKE. 156'S AND RUBBER MATS FOR THE WINTER.
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08-25-2006, 06:12 AM	#5
330m First Lieutenant 6 Rep 364 Posts Drives: 330i Join Date: Feb 2006 Location: Manchester iTrader: (0)	Many cars have these, probably as Dante says to break up air flow before it hits the rear tyre / suspension parts. __________________ *330i M-sport* SG + black leather :rocks:
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08-25-2006, 07:25 AM	#9
Gitta Kelly's 330i 11 Rep 413 Posts Drives: 330i Join Date: Feb 2006 Location: E PA iTrader: (0) Garage List 2006 330i (current ... [0.00] 2006 330i (new) [0.00] 2006 330i (interior) [0.00]	If you look underneath there is another set of air dams in farther too. __________________ '06 330ix \| 6MT \| TS-BDL-BW \| ZSP \| ZPP \| heated seats \|... mods \| cf splitters painted TiAg \| spoiler \| blacklines \| short shift knob \| cf trim \| *** winter setup: 17" ASA JH3 & Dunlop WinterSport M3 DSST * . '01 325xi \| auto \| TS-GDL-BW \| ZPP \| heated seats \|........... mods** \| spoiler \| mudguards \| blackout grills \| clear lights \| halo projector headlights \|
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08-25-2006, 09:04 AM	#10
larsssss Enlisted Member 0 Rep 49 Posts Drives: E91 325xi TiAg Join Date: May 2006 Location: Sweden iTrader: (0)	Cool. I was wondering the same thing.
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08-25-2006, 09:17 AM	#11
pauly1 Enlisted Member 1 Rep 45 Posts Drives: Nikes Join Date: Jul 2005 Location: ny iTrader: (0)	The flap is known as a kickdown. As a tire rotates it creates what's know as aero turbulence, the flap helps deflect air around the turbulent wheel and wheelwell. Hence, reducing drag on the car, which helps with performance and fuel consumption.
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08-25-2006, 11:30 AM	#13
SoYank Major General 571 Rep 7,519 Posts Drives: 2009 E90 335i MT Join Date: Mar 2006 Location: Vinton, Virginia iTrader: (1) Garage List 2009 BMW E90 335i S ... [9.00]	Airbrakes. __________________ **2009 E90 335i Montego Blue · Black Leather · Burl Walnut · 6MT · US Spec** SatNav • ZPP • ZCW • 6FL • TPMS • iDrive • PDC • HWS • Xenons • BMW Assist • Power Rear Sunshade • Logic 7 European Taillights • Rear Foglamp • OEM Alarm • PicoTray • DataToys XM-DVR • Multi-view Processor Quaife ATB LSD • Short Shift Knob • Hartge Anti-Roll Bars • AP Racing Front Brakes • 19" Style 269
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08-25-2006, 11:32 AM	#14
obLu Major 50 Rep 1,159 Posts Drives: 330i 6MT ZSP Join Date: Jun 2005 Location: Kirkland, WA, USA iTrader: (1)	OT - Andy, those 18" or 19" CSLs?
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08-25-2006, 11:32 AM	#15
Asiann Got Seoul? 116 Rep 2,862 Posts Drives: 2012 535i MSport Join Date: Dec 2005 Location: Honolulu iTrader: (0) Garage List 2012 BMW 535i [0.00] 2008 750Li [0.00] 2006 BMW [0.00]	I thought they were like curb alerts or something since they make this aweful noise when you get too close. __________________ Can you say Alooooha? [SIGPIC][/SIGPIC]
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08-25-2006, 03:57 PM	#18
ImUrGoDaK Private 12 Rep 63 Posts Drives: 05 325i to 08 335xi :) Join Date: Jul 2005 Location: SF iTrader: (1)	the flapgs reduce the airdrag created by the tires... says my mechanical enignering friend haha only works at high speeds... its probably not doing anything in the states
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08-25-2006, 05:31 PM	#20
just4kickz boku no namae ha... 336 Rep 11,025 Posts Drives: 2006 BS 330i Join Date: Feb 2006 Location: S. Bay Area, CA + Newark, NJ + ChiCity + True Blue iTrader: (11) Garage List 2006 E90 330i [0.00]	LOL i scratched my front ones the first day i got it... was still getting used to the length of my car while parking... geez lols __________________ looking for a PreLCI Black Sapphire e90 front bumper without license plate holes "Akimbo shotguns. Broken wrists anyone? And don't give me that 'it's just a game' bull**. Where the are my akimbo interventions then?! One scope on each eye mother**er!!"
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08-25-2006, 06:25 PM	#21
CnoteMD Commander in Chief 37 Rep 1,034 Posts Drives: 2008 BMW 535i Join Date: May 2005 Location: Atlanta, GA iTrader: (0) Garage List 2008 M5 [0.00] 2006 330i [0.00]	I am very glad that those flaps are there!!! About 2 months after buying my car, I saw a 8-10 inch piece of metal hanging off of one of those flaps (it was like a long metal wire, but about as thick as a coffee stirring straw). I took it too the dealer to see if something had broken off of my car. When they got down there, they saw that it was something from the road that actually punctured through the flap and ended up "attached" to my car. They simply pulled it out and threw it away. If it wasn't for that flap, it would have gone straight to my expensive and hard to find rear runflat tire! __________________ 2008 BMW 535i Space Gray, Black Leather, Dark Bamboo Trim\| Sport Automatic with Paddles \| Sport Package 2008 BMW M5 (gone, but not forgotten) Space Gray, Silverstone Merino Leather, Madeira Walnut Wood Trim \| 7speed SMG \| All options Mods: Corsa Exhaust \| RPI Ram Air Intake \| H&R Sport Springs \| Rogue Engineering 12mm spacers
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