Bajie

Bloody Miniscule ***** !
Parked in Heathrow a few months back a 22B was next to my Terzo.
His spoiler wasn't there.
It didn't look good.

Neil F

They wouldn't fit them to the WRC cars if they served no purpose (weight penalty).
I believe they generate downforce from around 50mph but I could be wrong (although that would be rare ;o) ).
Also, look how much difference the spoiler on an Audi TT makes; you can now take a long sweeping left-hander at 45 without going backwards!

Mike Rainbird

It serves as an excellent place to put your tea when cleaning the car....
LOL
Mike

KevMac

I’ve always wondered does the rear spoiler really make a difference or is it just for show?

I can see how it might keep the back stuck down on an autobahn at 100 plus but is it a waste on British and Irish roads where max legal speeds are 70.

The M5 has a tiny, tiny lip of a spoiler and that seems to be suffice.

Any ideas?

I Stancer

Yes of course it has a purpose , It reflects the size of the drivers' genitalia !!

You mention that( girls car )BMW . I rest my case

Ian

Paul Wilson

It also lowers the Cd of the car.
I know sounds stupid doesn't it.
But it is down to the effective angle between the back of the roof and the highest point at the back of the car (i.e. the spoiler) the angle without the spoiler is about 30 degrees which is the worst angle from a drag point of view. Go higher or lower and the Cd gets better.

The downnforce is more a reduction of the upthrust caused by the low pressure area at the rear of the car. The reduction happens because the pressure at the rear is now higher with the wing as the air is following a better path than the 30 degrees without the spoiler.

The shape of the wing acounts for only a tiny amount (if any) of the downforce as most of the air goes over the top of the wing, but an aerofoil shape is very "slippy".

Obviously the higher you go with a wing the more important the section of the aerofoil is (eg. Escort Cossie Whale Tail)

So yes, keep the wing you'll get better fuel economy and be able to go faster

At least thats what you can tell everybody

Paul

p.s. I knew that lecture would come in handy one day

steve McCulloch

Lets face it - it looks bloody good and everyone loves it

The only female that didnt like it was my gran!
And it brightens up anotherwise boring car.

As far as BMW goes all their cars are ****e anyway - do they do a sports car? test drove an M3 about 5 montsh ago and thought it had had a 1.6litre transplant!

Tommy

The standard spoiler (Pre MY99) definitely reduces drag. It does this because it provides a clean cutoff between the turbulent air behind the car and the air moving smoothly above it. By making the turbulent area smaller you reduce drag, and you can see that it works because the water runs smoothly down the rear window in the rain.

I'm not convinced that the bigger spoiler on a MY 99 works as well, as the rain on the back window moves all over the place, so there must be more turbulent air and so more drag. It ought to be better than a small one at reducing lift but won't be if it is in turbulent air.

In theory the twin spoilers on new STis and Prodrives should be much better, the bottom spoiler keeping the turbulent air behind the boot reducing drag and the top one able to work as an inverted wing in clean air. I've never diven one in the rain to see.

Glen Stenhouse

The only spoiler that is of any worth is the 22Bs. It is the only true inverted airfoil and the only one capable of creating downforce.

The low spoilers on WRXs are purely cosmetic as they create lift. The taller STi ones are indifferent.

On the other hand a Cosworth spoiler generates around 180kg of downforce at 200kph. Might look a bit funny on a Type R though.

Gethin

A Subaru employee once told me the 22b's spoiler needs to be properly set up in a wind tunnel and tweaked or it messes up the airflow properties quite badly....hmm..

RoShamBo

iTrader: (1)

Doesn't the P1 spoiler "save" 3bhp @ 100mph or something....?
But again that is adjustable so would need to be set up right.

Ro

Paul Wilson

Looks can be decieving.
which two of the following have roughly the same Cd?

Scooby
Jaguar D-Type
VW camper van

answer tommorow

mike_nunan

Tommy,

My car came with the MY00-type spoiler, but I swapped it for the old-style low spoiler for purely cosmetic reasons (see, not everyone thinks it looks good!)

Anyway, I can confirm that the behaviour of water on the rear screen is the reverse of what you describe. With the low spoiler, the water hangs about, running in circles around the middle of the screen. With the higher spoiler, it still had a tendency to hang about at bit, but not as badly as it does now. Sometimes it almost looks like there's a big puddle forming on my rear window!

I don't know about the effect of the 22B spoiler (or the ScoobySport one, which also has a proper aerofoil shape) but it would certainly be interesting to do a with-and-without comparison at a track day sometime.

TTFN

-= mike =-

Andy_T

In Australia, the spoiler serves no real purpose as the speed limit of 110 km/h is enforced using draconion measures. So the lip spoiler on e.g. the M5 is really there only because it is there in other markets - Germany, for example. And for the person above who asked if BMW makes sh*te sports cars, or something, well if the M3 isn't enough (someone must have stitched you up mate!) the abovementioned M5 will probably do. 0-60 in 4.6 sec, assuming that this is the most important measurement for you.

Andy T

Tommy

When I got my MY99 I noticed the water in puddles on the back window, and thought I'd never noticed it on my previous MY96, so I concluded that it must have been smoother.

Obviously not scientific enough!

Diablo

Guys, its not about reducing drag, its about reducing lift.

Spoilers do just that, they spoil the airflow thus reducing the lift effect of the air flowing faster accross the top of the car. The little ones on the Audi TT are for this purpose. Wings create downforce, or at least they are supposed to.

Thus, lip type spoilers are to create turbulence, Wing type spoilers are to create downforce. In each case, drag is increased.

D.

sunilp

Forget all the theory, it looks damn impressive and makes the drivers **** 18 inches larger...erm, which gives me 18.5 inches

DocJock

Sounds like the best answer to me Sunilp.

Err...where can I fit it on my 5door ???

sunilp

Doc, on a 5dr it has to be roof mounted!
By doing this, you will have an even greater manhood than any 4dr owner!

Diablo

Sunil,

We can always rely on you to lower the tone, eh?

Reading too much Max Power again. Makes you go blind, you know.......

D.