what IS this thing?

BMCoupe_782 · 08-30-2011, 10:52 PM

Just had some m3 sideskirts installed and noticed these little "black flaps" underneath the car - near the sideskirt.

Just want to make sure I'm not crazy - what the hell are these little black flaps called and why are they there? Are they supposed to be?

Thanks

AndreyT · 08-30-2011, 11:13 PM

You are actually supposed to have 4 of these: 2 in the front and 2 in the rear. I'd guess that this has something to do with the wheel well aerodynamics. Maybe they reduce drag. Maybe they somehow reduce the amount of spray from under the wheels or something along these lines.

BMCoupe_782 · 08-30-2011, 11:20 PM

I actually think they look stupid. Wish I could remove. Maybe I'm just getting way too OCD over the car but I found myself staring at them from a distance and thinking they ruined the look of the car. haha.

Thanks for the input.

Ghoti · 08-30-2011, 11:22 PM

I think AndreyT has it ... they improve aerodynamics around the wheels, and help prevent debris from getting up in the wheel well.

hogbmw · 08-30-2011, 11:24 PM

Hmmm. mine are pretty thrashed from my intensely steep driveway. not sure if aerodynamics come into play in my case

Bme30 · 08-30-2011, 11:34 PM

gangster mud flaps lol

BMCoupe_782 · 08-30-2011, 11:36 PM

^ lol

tibra1 · 08-30-2011, 11:40 PM

They are mud flaps..but yours really protrude downwards..mine sit much more flush..weird

AndreyT · 08-30-2011, 11:59 PM

They are actually installed in front of each wheel well, not behind it. A rather unusual location for mud flaps (unless these are special mud flaps for driving in reverse).

schulrog · 08-31-2011, 12:05 AM

they are called mudflaps and do absolutely nothing for aerodynamics... the cars are so low that rocks don't get kicked up anyway. I had them on my E64 and they looked absolutely retarded so i just tore them off

AndreyT · 08-31-2011, 12:10 AM

Quote:

Originally Posted by schulrog

they are called mudflaps and do absolutely nothing for aerodynamics...

Incorrect. They are not called mudflaps (unless you are talking about some "opposite world" version of mudflaps). Mudflaps are installed on the rear edge of the wheel well, not on the front edge. These are mudflaps

http://www.google.com/search?rlz=1C1...=1920&bih=1113

BMW sells OEM mudflaps as well, as far as I know. Mudflaps have absolutely nothing to do with what is being discussed here. What you see in the picture in the first post is located in front of each wheel. It is there purely for the aerodynamics.

tibra1 · 08-31-2011, 12:20 AM

What aerodynamics?...to create more drag..

AndreyT · 08-31-2011, 12:26 AM

Quote:

Originally Posted by tibra1

What aerodynamics?...to create more drag..

Well, you see, how do I break this to you... er... aerodynamics is a bit more complicated than a mere "create more drag" and a smiley.

My first guess would be that these flaps are there to convert the laminar airflow into turbulent one right before this airflow hits the wheel well. It is quite possible that by intentionally disturbing and/or deflecting the airflow in front of the wheel well we will actually reduce the total drag (considering how non-aerodynamic various suspension arms are). Just an educated guess.

It is not the first time this question is asked here

http://www.e90post.com/forums/showthread.php?t=184575
http://www.e90post.com/forums/showthread.php?t=350865

Lots of theories... The last answer in the first thread is probably the right one.

P.S. And, finally, the correct answer: The technical name for this part is wheel spat (not necessarily the official BMW nomenclature). They have been used in various forms on various cars to reduce the aerodynamic drag for a while already. Here's some easily visible on a Toyota iQ

Apparently some fuel efficiency affectionados put some effort into tuning these things.

BMCoupe_782 · 08-31-2011, 09:07 AM

I'm definitely getting rid of these (now I realize they're not really necessary/functional in my eyes) it just gives the car a cleaner look from the side.

FRRYY · 08-31-2011, 01:48 PM

these always fake me out when i approach a steep driveway. I keep thinking i'm scraping my bumper, but its usually these that are the ones that scrape.

schulrog · 09-01-2011, 03:23 PM

ah yes i guess they are infront of the wheel instead of behind... regardless... they look out of place and i am sure there is minimal benefit in terms of aerodynamics

ZURICH · 09-01-2011, 03:56 PM

OK guys, here starts the first lesson in Areodynamics "short version"

the little flaps prior to each wheel were first introduced by honda, having been first trialed on their Formula one cars.

They are called: "Air Dams"

Reason for fitting: they reduce under floorpan turbulance and drag, a totally flat underside produces downforce, any other floorpan creates voirtices dragging debris and water off the road surface onto the underside of the car. reducing downforce

The Air Dams create specific and directed air flow eliminating the disturbing and unwanted iregular drag factor creating airflow and reducing the ammount of crap thrown up onto the underside of the car, OK! GOT IT? GOOD

edirtaynine · 09-01-2011, 03:58 PM

these are not mudflaps/mudguards/whatever. these are placed in front of each wheel/tire to help with the airflow go AROUND the wheel/tires.

mr_milo · 09-01-2011, 04:06 PM

Quote:

Originally Posted by ZURICH

OK guys, here starts the first lesson in Areodynamics "short version"

the little flaps prior to each wheel were first introduced by honda, having been first trialed on their Formula one cars.

They are called: "Air Dams"

Reason for fitting: they reduce under floorpan turbulance and drag, a totally flat underside produces downforce, any other floorpan creates voirtices dragging debris and water off the road surface onto the underside of the car.

The Air Dams create specific and directed air flow eliminating the disturbing and unwanted iregular drag factor creating airflow and reducing the ammount of crap thrown up onto the underside of the car, OK! GOT IT? GOOD

Believe it or not, they also help keep water out of the wheel wells and off of your brake. I had a wet breaking problem on my Audi A4 and after months of working with Audi they finally fitted my car with a version of these. Afterwards my wet braking problem was gone!

ZURICH · 09-01-2011, 04:13 PM

Quote:

Originally Posted by mr_milo

Believe it or not, they also help keep water out of the wheel wells and off of your brake. I had a wet breaking problem on my Audi A4 and after months of working with Audi they finally fitted my car with a version of these. Afterwards my wet braking problem was gone!

Exactly, correctly directed airflow is good engineers spend years designing,testing, throwing out and finally "hooray it works" fitting small details to cars, not to make them look cool but to improve stability under accelaration and breaking, these babies help enormously in straightline freeway, Autobahn cruising, by keeping the shit off all our important parts.

JS82 · 09-01-2011, 08:06 PM

Those things saved my front bumper from scratching.

NiVeDh · 09-01-2011, 09:11 PM

I cut them off.

08-30-2011, 10:52 PM	#1
BMCoupe_782 Bavarian Fever 34 Rep 1,108 Posts Drives: 08' e92 328xi TiAg Join Date: Oct 2007 Location: Queens, NY / North NJ iTrader: (4)	what IS this thing? Just had some m3 sideskirts installed and noticed these little "black flaps" underneath the car - near the sideskirt. Just want to make sure I'm not crazy - what the hell are these little black flaps called and why are they there? Are they supposed to be? Thanks Attached Images __________________ \| ESS n52 Tune \| BMW Performance Intake/Exhaust \| LUX H8 v3 AE \| GP Thunder 8500K fogs/corners \| LED: signals/interior \| V1 hardwired \| debadge \| AC pedals \| Performance shift knob/boot \| CF e-brake \| Aero lip \| m3 side skirts/spoiler \| MB kidneys \| Strut brace \| Painted reflectors \| Painted Calipers/Hubs \| 35% 3M tint \| Smoked tails \| CF Roundels \| 19" Miro 942 \| Conti DWS \| H&R Springs for xi \| Bilstein Shocks\| Nxt: Alpine Subs/Amps
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08-30-2011, 11:13 PM	#2
AndreyT Major 57 Rep 1,038 Posts Drives: 2011 335i Sedan, Sport Join Date: Feb 2011 Location: Northern California iTrader: (0)	You are actually supposed to have 4 of these: 2 in the front and 2 in the rear. I'd guess that this has something to do with the wheel well aerodynamics. Maybe they reduce drag. Maybe they somehow reduce the amount of spray from under the wheels or something along these lines. Last edited by AndreyT; 08-31-2011 at 12:02 AM..
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08-30-2011, 11:20 PM	#3
BMCoupe_782 Bavarian Fever 34 Rep 1,108 Posts Drives: 08' e92 328xi TiAg Join Date: Oct 2007 Location: Queens, NY / North NJ iTrader: (4)	I actually think they look stupid. Wish I could remove. Maybe I'm just getting way too OCD over the car but I found myself staring at them from a distance and thinking they ruined the look of the car. haha. Thanks for the input. __________________ \| ESS n52 Tune \| BMW Performance Intake/Exhaust \| LUX H8 v3 AE \| GP Thunder 8500K fogs/corners \| LED: signals/interior \| V1 hardwired \| debadge \| AC pedals \| Performance shift knob/boot \| CF e-brake \| Aero lip \| m3 side skirts/spoiler \| MB kidneys \| Strut brace \| Painted reflectors \| Painted Calipers/Hubs \| 35% 3M tint \| Smoked tails \| CF Roundels \| 19" Miro 942 \| Conti DWS \| H&R Springs for xi \| Bilstein Shocks\| Nxt: Alpine Subs/Amps
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08-30-2011, 11:22 PM	#4
Ghoti Second Lieutenant 9 Rep 289 Posts Drives: 335i Join Date: Aug 2011 Location: Toronto iTrader: (0)	I think AndreyT has it ... they improve aerodynamics around the wheels, and help prevent debris from getting up in the wheel well. __________________ SG e92 335i 6MT / Pure Stg2 DD / JB4 + MHD BEF / ETS FMIC / Dinan CAI / AR DPs / Stage 2 LPFP / Spec 3+ / Spec SMFW / MFactory LSD / KW V2 SCs / Vibrant 1792s e36 M3 ... gone but not forgotten
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08-30-2011, 11:24 PM	#5
hogbmw Private First Class 5 Rep 160 Posts Drives: '07 BMW 328i Join Date: Jul 2011 Location: Fayetteville, AR iTrader: (0)	Hmmm. mine are pretty thrashed from my intensely steep driveway. not sure if aerodynamics come into play in my case __________________ '07 328i-Saphire Black Murdeerrrrred-gone '08 335i-Black on Gold.. work in progress!-JB3-DCI
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08-30-2011, 11:34 PM	#6
Bme30 Major 88 Rep 1,039 Posts Drives: 335i coupe Join Date: May 2010 Location: 'Merika' iTrader: (2) Garage List 2007 335i [0.00]	gangster mud flaps lol
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08-30-2011, 11:36 PM	#7
BMCoupe_782 Bavarian Fever 34 Rep 1,108 Posts Drives: 08' e92 328xi TiAg Join Date: Oct 2007 Location: Queens, NY / North NJ iTrader: (4)	^ lol __________________ \| ESS n52 Tune \| BMW Performance Intake/Exhaust \| LUX H8 v3 AE \| GP Thunder 8500K fogs/corners \| LED: signals/interior \| V1 hardwired \| debadge \| AC pedals \| Performance shift knob/boot \| CF e-brake \| Aero lip \| m3 side skirts/spoiler \| MB kidneys \| Strut brace \| Painted reflectors \| Painted Calipers/Hubs \| 35% 3M tint \| Smoked tails \| CF Roundels \| 19" Miro 942 \| Conti DWS \| H&R Springs for xi \| Bilstein Shocks\| Nxt: Alpine Subs/Amps
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08-30-2011, 11:40 PM	#8
tibra1 Banned 127 Rep 6,773 Posts Drives: 2011 ZCP M3 - 2007 335i crashd Join Date: Apr 2009 Location: NYC iTrader: (4)	They are mud flaps..but yours really protrude downwards..mine sit much more flush..weird
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08-30-2011, 11:59 PM	#9
AndreyT Major 57 Rep 1,038 Posts Drives: 2011 335i Sedan, Sport Join Date: Feb 2011 Location: Northern California iTrader: (0)	They are actually installed in front of each wheel well, not behind it. A rather unusual location for mud flaps (unless these are special mud flaps for driving in reverse).
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08-31-2011, 12:05 AM	#10
schulrog First Lieutenant 14 Rep 318 Posts Drives: BMW 645CiC Join Date: Dec 2007 Location: Montana iTrader: (4)	they are called mudflaps and do absolutely nothing for aerodynamics... the cars are so low that rocks don't get kicked up anyway. I had them on my E64 and they looked absolutely retarded so i just tore them off
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08-31-2011, 12:20 AM	#12
tibra1 Banned 127 Rep 6,773 Posts Drives: 2011 ZCP M3 - 2007 335i crashd Join Date: Apr 2009 Location: NYC iTrader: (4)	What aerodynamics?...to create more drag..
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08-31-2011, 09:07 AM	#14
BMCoupe_782 Bavarian Fever 34 Rep 1,108 Posts Drives: 08' e92 328xi TiAg Join Date: Oct 2007 Location: Queens, NY / North NJ iTrader: (4)	I'm definitely getting rid of these (now I realize they're not really necessary/functional in my eyes) it just gives the car a cleaner look from the side. __________________ \| ESS n52 Tune \| BMW Performance Intake/Exhaust \| LUX H8 v3 AE \| GP Thunder 8500K fogs/corners \| LED: signals/interior \| V1 hardwired \| debadge \| AC pedals \| Performance shift knob/boot \| CF e-brake \| Aero lip \| m3 side skirts/spoiler \| MB kidneys \| Strut brace \| Painted reflectors \| Painted Calipers/Hubs \| 35% 3M tint \| Smoked tails \| CF Roundels \| 19" Miro 942 \| Conti DWS \| H&R Springs for xi \| Bilstein Shocks\| Nxt: Alpine Subs/Amps
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08-31-2011, 01:48 PM	#15
FRRYY First Lieutenant 25 Rep 399 Posts Drives: 2008 AW e92 Join Date: Aug 2011 Location: Los Angeles iTrader: (1)	these always fake me out when i approach a steep driveway. I keep thinking i'm scraping my bumper, but its usually these that are the ones that scrape.
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09-01-2011, 03:23 PM	#16
schulrog First Lieutenant 14 Rep 318 Posts Drives: BMW 645CiC Join Date: Dec 2007 Location: Montana iTrader: (4)	ah yes i guess they are infront of the wheel instead of behind... regardless... they look out of place and i am sure there is minimal benefit in terms of aerodynamics
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09-01-2011, 03:56 PM	#17
ZURICH Major 41 Rep 1,153 Posts Drives: E91 320d Touring M Sport Join Date: Jul 2011 Location: Wettingen iTrader: (0)	OK guys, here starts the first lesson in Areodynamics "short version" the little flaps prior to each wheel were first introduced by honda, having been first trialed on their Formula one cars. They are called: "Air Dams" Reason for fitting: they reduce under floorpan turbulance and drag, a totally flat underside produces downforce, any other floorpan creates voirtices dragging debris and water off the road surface onto the underside of the car. reducing downforce The Air Dams create specific and directed air flow eliminating the disturbing and unwanted iregular drag factor creating airflow and reducing the ammount of crap thrown up onto the underside of the car, OK! GOT IT? GOOD __________________ M Sport Package, (PDC), front / rear, Cruise control Mystic Blue Metallic, Beige Dakota leather, Alarm, Automatic transmission, Panoramic glass roof, Heated Seats, Lumbar etc etc "I don't Fuck around but when I do, I dont fuck around" Last edited by ZURICH; 09-01-2011 at 04:06 PM..
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09-01-2011, 03:58 PM	#18
edirtaynine Major General 81 Rep 6,092 Posts Drives: e92 Join Date: Mar 2011 Location: SoCal iTrader: (0)	these are not mudflaps/mudguards/whatever. these are placed in front of each wheel/tire to help with the airflow go AROUND the wheel/tires.
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09-01-2011, 08:06 PM	#21
JS82 Captain 29 Rep 659 Posts Drives: '08 E92 328i 6MT Jet Black Join Date: May 2010 Location: PA USA iTrader: (12)	Those things saved my front bumper from scratching.
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09-01-2011, 09:11 PM	#22
NiVeDh Major General 422 Rep 8,003 Posts Drives: '08 E90 335i, '99 E36 M3 Join Date: Apr 2009 Location: Houston, TX & Atlanta, GA iTrader: (132) Garage List 2008 BMW 335i Sedan [8.66]	I cut them off.
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