does the rear wing on a BX really do anything

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Mike P
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Post by Mike P »

I'm with Kitch, they don't do anything.

LOOS in a 16v :lol:

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Post by Defender110 »

citronut wrote:i think the plastic at the front edge of the rear wings is more to stopnstoe chips,
Or sausages????? :lol:
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Des Smith
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Post by Des Smith »

johnbird wrote:this is a proper spoiler
Is that because it spoils the view? :)
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Des Smith
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Post by Des Smith »

Or sausages????? :lol:
Definitely not sausages. It'll be deepfried dogleg and chips
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BX Meteor
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Post by BX Meteor »

I always thought the wing was for show, but I'm not so sure after reading some of the posts.

I don't think that Citroen would really bother to add something like a rear wing for cosmetic reasons. I knew someone in 1990 who worked at Gaydon on the Rover ECU (MEMS) and he told me that for every £1 saved on the cost of a part, that was a considerable saving to Rover over the number of cars made. I would think that when Citroen became part of PUG, they had to think the same way.

So to add a lump of plastic at the back of a car for purely cosmetic reasons would be unjustifiable, unless engineering or marketing (or both) could justify it.

Having read bits on the internet and what some of you have put, the airflow over the top of the car is laminar so the flow is fast. Without the wing, the flow breaks up at the edge below the rear windscreen, creating a large amount of vacuum (drag) behind the rear number plate, and maybe some undesirable lift at the edge. By placing a diffuser in the stream of air, it is possible that whilst creating turbulence off the rear edge of the diffuser (the "wing"), the laminar flow over the rear windscreen is disrupted and so the amount of vacuum behind the rear number plate is reduced, as well as reducing the lift effect. Possibly less drag and less lift. They certainly would not add it if it increased drag as well as cost ?

I always thought the wing was for show, to make it look intimidating, but as I say I don't think that PUG would allow this on cost, unless it serves some benefit. At 85mph, a typical crusing speed in France at the time, it may have been shown to increase fuel efficiency by a small l/km (1mpg equiv) which would look good to marketing.

I suppose the Citroen engineers involved would sill be alive, maybe still at Citroen, it would be interesting to know the reality.

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Post by KevR »

BX Meteor wrote: I always thought the wing was for show, to make it look intimidating, but as I say I don't think that PUG would allow this on cost, unless it serves some benefit.
The benefit would be that it persuaded a small but significant percentage of punters to pay well over the odds for an illusory performance benefit. You can make more money persuading someone to pay £100 extra for a bit of bling that costs you a tenner than by saving a couple of quid elsewhere. Depends on markets too: sad though it may be, by the time the BX sprouted spoilers in the UK Citroën were no longer pushing technological innovation as a plus point. Instead they were tarting them up with fripperies to try and flog them to sceptical buyers who were terrified of funny suspension in particular and of anything that didn't come with an oval blue badge on it in general. That's why so many BXs in UK are high spec, with electric windows, sunroofs, central locking, extra trim - it was the only way to sell them... In France, where people still kept buying them anyway so they didn't need to discount them, you were much more likely to end up with an absolute base model - until the very end of production you'd be lucky to get electric start let alone electric windows.

Which is a long (and half-pissed) way of saying: BX rear spoiler? Cosmetic, pure and simple. If it helps keep your rear screen clear you can bet it's a bonus, not part of the design. :wink:
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Post by BX Meteor »

Yep, you are almost certainly right, I think I was trying to convince myself the wing did something by using a bit of science.

There are 3 ways to look at this logically:

(i) the wing does nothing at all to drag or anything else. If this is true then it's a purely marketing idea dictated down to engineering to implement. If PUG did market research (it is possible) then they had probably found that the BX Mk1 was looking tired. Indeed back then I would not have bought another BX as I began to think it looked jaded, but when I saw the rear wings on the BX I thought it looked better. I seem to remember that the PUG equivalent, the 405, also started sprouting a wing on its boot lid.

(ii) the wing increases drag slightly but otherwise does nothing. Similar argument as (i).

(iii) the wing actually reduces drag a tiny bit. If true then it's an engineering idea, but marketing would not give a damn about it unless it made a significant improvement that could be used in advertising, so a tiny improvement would not be worth implementing.

I don't necessarily think that the extra cost of the lump of plastic enabled Citroen to bump up the price, I think it enabled them to reduce a decline in sales i.e. over the lifetime of the BX, the lump of plastic mid-way through the product's lifecycle means that more cars were sold over that lifecycle

So yes, the BX rear wing was probably a small cost to marketing if it made the car look more competitive at the time. Today I think the BX looks daft with the wing in place, a bit like a wide-mouthed-toad looking for trouble, so I am tempted to remove it.

Any ideas, apart from blu-tack, to fill the holes ?

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Post by citronut »

or maybe even dog leg sausages and chips :roll: :oops:


citroen have always been airodinamicly minded, so it is probaly to do with this in some way,


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Post by Des Smith »

BX Meteor wrote:I am tempted to remove it.
Me, too. Some seriously erudite comments on airflow and downforce, but I keep coming back to reduced rear view vision. There are enough blind spots on the BX without adding another across the back that can potentially mask a fast moving bike or car if you look at the wrong time.

The wing on my BX is in need of a makeover and a respray, so it has to come off anyway. Whether it goes straight back on depends more on finding some aesthetically pleasing blanking grommets than enhancing adhesion or drag reduction.

As mentioned above, it would be good to find out from the horse's mouth ie the citroen design engineers of the day, whether there was any science behind the pose value of a wing.

Des
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Matt H
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Post by Matt H »

Des Smith wrote:
BX Meteor wrote:I am tempted to remove it.
Me, too. Some seriously erudite comments on airflow and downforce, but I keep coming back to reduced rear view vision. There are enough blind spots on the BX without adding another across the back that can potentially mask a fast moving bike or car if you look at the wrong time.
You should try driving a latest gen Honda Civic or CR-Z... Anything modern TBH. I find the biggest limitation on rear-view visibility is the sloping roofline, although it might just affect me because I'm tall?

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Post by Brian »

I posed this same query some time back. and IIRC, there was no definate conclusion.

So, I still maintain that the spoiler/wing does have one main use:
stops the shopping falling off the tail gate, but in doing so adds extra load onto the gas struts !!!.

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Des Smith
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Post by Des Smith »

Brian wrote:stops the shopping falling off the tail gate
No Brian, You're supposed to lift the tail gate and put the shopping inside!
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rayfenwick
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Post by rayfenwick »

IMHO it's fashion, pure and simple. Back in the 80's, funny wings, vents etc were everywhere - they differentiated the performance models from the cooking models for Joe Public: "It must be fast - look at that spoiler..."

A spoiler's name is a big clue to its purpose - it spoils (geddit?) the airflow. In most cases this is to provide extra downforce onto the rear wheels, which in most cases where necessary are the driving wheels.

It's there to reduce oversteer, to prevent the rear sliding out under cornering - given the BX is front wheel drive (excluding the 4x4, naturally...) the spoiler isn't likely to do anything positive for the handling. (I can believe that it helps on a CX, because they are VERY nose-heavy, but I don't think that applies to the BX?)

It is certainly negative as far as drag coefficient and therefore fuel consumption are concerned. But it looks cool...to some.

Personally, I like the purity of the early BX, but also like the skirts and spoiler looks of the GTi's.
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Post by Way2go »

rayfenwick wrote: they differentiated the performance models from the cooking models for Joe Public: "It must be fast - look at that spoiler..."

Personally, I like the purity of the early BX, but also like the skirts and spoiler looks of the GTi's.
True - the spoiler originated on the GTi & 16v but seemed to become such a reason to buy that it was devalued really by migrating it to the less-responsive cars.

Strange that now so many years later many are posting their dislike of it. It's almost as if some now think it's fashionable to dislike it.

I still like it and disagree that it impedes rear vision by much as I only see it's thickness & no more- perhaps if your head/eye height is different in the car to me then the vectoring creates a larger apparent thickness.

It may even have a purpose in help keeping rain off the rear window as it's always clear of rain when the cars moving. :D :wink:
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Post by BX Meteor »

At a set of traffic lights, when a modern Golf Diesel comes alongside, my 1.6 BX with its wing is a wide-mouthed-toad ....

One day a wide-mouthed-toad decided to leave his pond and see the world.

He came across a big brown animal and he said "I'm very hungry, what animal are you and what do you eat". The animal replied "I'm a cow and I eat grass". The toad replied "I'm a wide-mouthed-toad and you sound like a loser" and he scuttled off.

Next he came across a big black animal and he said "I'm very hungry, what animal are you and what do you eat". The animal replied "I'm a black bear and I eat berries and sometimes fish". The toad replied "I'm a wide-mouthed-toad and you sound like a loser" and he scuttled off.

Next he came across a big greenish animal and he said "I'm very hungry, what animal are you and what do you eat". The animal replied "I'm a crocodile and I eat big animals but I also find toads rather tasty". The wide-mouthed-toad screwed up his mouth and said "I'm just a little frog, must go" and he hopped back to his pond.

...... Why keep a posey wing on the back of a 1.6 BX (rhetorical) , in the 90's the 1.6 was fairly quick, by today's standards its performance is mediocre and the wing is too attention-seeking for my liking. It's coming off, I'll go to B&Q and see if I can find any grommets, that way I can drive my BX and feel that I have a modest car that is just simple to maintain and nice to drive.