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  1. #1
    Fellow Frogger! 30780Y's Avatar
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    Hi guys
    Just a silly ques.....
    I have a spoiler on my car, which i added as an option when i 1st purchase the car...... i wanted it because i thought will look good......But is it all it does, the LOOKS??? Is there any idea other use???

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    I might be slow... DRTDVL's Avatar
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    i'd say it (the factory one) would have a very small effect on the cars handling, but not to much...

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    Fellow Frogger! 206 RC's Avatar
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    Quote Originally Posted by 30780Y
    Hi guys
    Just a silly ques.....
    I have a spoiler on my car, which i added as an option when i 1st purchase the car...... i wanted it because i thought will look good......But is it all it does, the LOOKS??? Is there any idea other use???
    Well, on a 307 I would be very surprised if the provided down force of a spoiler is required. Generally on road cars they are all about looks.

    On sports cars, for instance the 405 T16 a spoiler is required to prevent the vehicle from becoming a short range ground to air missile.
    Last edited by 206 RC; 30th May 2005 at 05:02 PM.
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    Banned orestes's Avatar
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    As others have said spoilers in genral create downforce. On a 307 however it would be purely for show

  5. #5
    I might be slow... DRTDVL's Avatar
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    if you where after more downforce, you could get a aftermarket spoiler and sell the original to fund it...

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    Fellow Frogger! 206 RC's Avatar
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    Quote Originally Posted by DRTDVL
    if you where after more downforce, you could get a aftermarket spoiler and sell the original to fund it...
    More downforce = more drag = more petrol consumption = zero handling benefits.

    Would probably be negligible however in theory that would be the outcome
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  7. #7
    I might be slow... DRTDVL's Avatar
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    i'd tend to dissagre with the zero handling benifits, depending on the spoiler and it's design they can be very funtional, i've drivin a few cars with aftermarket spoilers (designed for functionality not for looks) and you can definatly notice the differance

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    Fellow Frogger! 206 RC's Avatar
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    Quote Originally Posted by DRTDVL
    i'd tend to dissagre with the zero handling benifits, depending on the spoiler and it's design they can be very funtional, i've drivin a few cars with aftermarket spoilers (designed for functionality not for looks) and you can definatly notice the differance
    At low speeds I would be very suprised. At high speeds I would agree.
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  9. #9
    I might be slow... DRTDVL's Avatar
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    obviously they work better at speed as there is more force attacking on the spoiler therefore generating more force...

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    Quote Originally Posted by ashvsaod
    On sports cars, for instance the 405 T16 a spoiler is required to prevent the vehicle from becoming a short range ground to air missile.
    yeh i cant wait to be rolling in one o them...

    the simple fact is most cars arent ever going to go fast enough or corner hard enough to need a spoiler

    in my case im almost certain the 405 spoiler is purely for looks

    isnt there also some fact that front wheel drives dont need spoilers anyway? im no aeronautical engineer but ive heard that somewhere i think lol

    but lets be honest, some spoilers just look plain cool
    '92 405 mi16

  11. #11
    I might be slow... DRTDVL's Avatar
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    the type of drive don't really matter...

    for example if you where to put a say front spoiler (be it a adjustable lip, wings on the side of the bumpers, etc..) it would push the front of the car downwards... this helping to provide more grip to the front end, this would help with understear...

    It depends on the angles and size of the wing.... just think about your hand out the window when the car is moving, even at 50kph your hand still gets moved around... now apply that to the front of the car or the rear of the car...

    next time your driving stick you hand out the window and tilt it at different angles, you then will get an idea of why the angle of the spoiler matters soo much...

    my friends drag car, if he runs an extra 2 degrees on his rear spoiler he will lose if i remember correctly a couple of kph at the top end but gains more traction allowing him to put the power fully down earlier... depending on the track's grip at the time he can run more or less angle on the spoiler... same applies for road and track use...

  12. #12
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    A rear spoiler on a hatchback will not only not provide significant handling benefit, it may provide extra drag which will decrease fuel efficiency.

    The idea of a spoiler is to provide a downward force, it's true. In a drag racing car which is light, has fat wheels and a ridiculously powerful engine it makes all the difference. The tradeoff is between wind resistance and tyre grip. In a street car which has narrow wheels, is heavy, and has a very large body anyway, there is already a good deal of wind resistance and downward force and you won't get significantly more tyre traction with a small spoiler. The spoiler would have to be ridiculously large - almost as big as the car - to make a noticeable difference. Furthermore as nick86 mentioned already, if a rear spoiler that is behind the rear wheel does provide downward force, then it will actually serve to push down on the rear wheel and lift up on the front, which is where the drive wheels are. So nick86's comment does stand in theory, even though it really won't make a measurable difference.

    The good news is that hatchbacks look good with a spoiler, and small spoilers don't provide too much drag, especially if factory fitted.

    Edit: Oooh check this out:
    http://www.answerbag.com/q_view.php/3725
    • In nearly all instances where spoilers are mounted on regular street cars, the spoiler is mounted to the trunk lid. How strong is that trunk lid? What do you think would happen if the spoiler, mounted on the trunk lid, really did exert an amount of force comparable to a significant portion of the car's weight. Let's say, several hundred pounds at least. Do you think the effect would be anything other than to violently rip the trunk lid off of the car?

    • Most modern cars — including nearly all of those on which you ever see spoilers mounted, are front-wheel drive. You'd want the extra downward force to be on the FRONT wheels; yet spoilers are nearly always mounted on the rear.
    Last edited by Matt Ray; 30th May 2005 at 11:30 PM.
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  13. #13
    Moderator Alan S's Avatar
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    I think spoilers can have more effect on a car than at first we might think based on my own experiences with them.

    On a CX where I fitted a spoiler, I could feel it start to work at around 80KPH. The rear would sink and then as the speed rose, the hydraulic suspension would self level. What good did it do? Give me more bite on the rear wheels on a FWD car that doesn't tail wag to begin with.

    Second effort was a people mover a Ford Spectron high roof XLT that had a factory fit front air dam. At 110KPH the front got very light. One night, very late I am passing an island cab style timber truck at Gunalda and I am doing about 110+ as I approach hime and quick as a wink as the air from the underbody tunnel on the truck hits me, I feel the front wheels leave the road Fortunately I have had enough years of experience to bring it down safely, but in either of these cases I have o ask, do I really need them?
    I'd feel safer with a factory fit rather than an after market job, but in the case of the Ford, this was fitted by Ford as a method of decorating a badge engineered vehicle so obviously wasn't considered as a performance article as much as a decorative one. Result could have been disastrous.

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  14. #14
    I might be slow... DRTDVL's Avatar
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    as alan said, a spoiler will do more than you will think, anything that creates and force will effect the cars handling, that the reason why the design of the bonnet, wing mirrors, windscreen angles, etc... will effect the cars handing...

    it doesn't really matter how small the spoiler is it will have some effect on the cars handling as it's still generating some force... look at the f1 cars with the mid-car mounted little spoilers on the intake housing...

    i argree that most people only concentrate on rear spoilers as they are more visiable and tend to look based... but for all cars a spoiler in the front would be benifishal (spelling - ugh mind is being fried with assignments) as front end grip is how you turn corners...

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    1000+ Posts cruiserman's Avatar
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    Most of them are for looks, but as a good selling point they are great places to stick the "please return to woolworths" sticker, just to reinforce the fact that lots look like shopping trolley handles.
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    Fellow Frogger! chris's Avatar
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    While on the whole I'd agree that spoilers on road cars mostly just suggest something about the driver, some of the factory jobbies are very carefully designed and actually reduce drag. Take a look at this page:

    http://www.citroen.mb.ca/citroenet/html/a/aero01.html

    Scroll down a bit and there's a blurb about how adding a small spoiler and a few other minor changes knocked 7% off the drag of the GSA, which is a pretty slippery car to begin with.

    The back of most cars actually generates a lifting force while in motion, and where you induce lift you generally induce drag too. If a spoiler interferes with the lift component it can reduce the amount of drag induced...

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    Fellow Frogger! casnell's Avatar
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    Quote Originally Posted by chris
    While on the whole I'd agree that spoilers on road cars mostly just suggest something about the driver, some of the factory jobbies are very carefully designed and actually reduce drag. Take a look at this page:

    http://www.citroen.mb.ca/citroenet/html/a/aero01.html

    Scroll down a bit and there's a blurb about how adding a small spoiler and a few other minor changes knocked 7% off the drag of the GSA, which is a pretty slippery car to begin with.

    The back of most cars actually generates a lifting force while in motion, and where you induce lift you generally induce drag too. If a spoiler interferes with the lift component it can reduce the amount of drag induced...

    Cheers,
    Chris
    Some spoilers are certainly designed to provide down-force, the EVO one is definitely designed this way and does work well at speeds as low as 60-70 ks. This is evidenced by the photos from Canberra where the dust is swirling up a lot, and at WRC level it's amazing to see the dust etc flung up into the air by the updraft when cars pass. However, at normal speeds this is probably irrelevant, and lots of spoilers actually are designed to lower drag. The vortex generators fitted to new BMW's and the EVO9 are classic examples of something designed to stick out and actually lower drag, not cause it...
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  18. #18
    Real cars have hydraulics DoubleChevron's Avatar
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    My old CX has a massive boot spoiler and a front air dam. I think original cars were plenty stable enough at 100mph, though I've been told by the guys in the UK that hammer there CX's up and down the auto-barns and motorways that the car is far more stable at 140mph with the boot spoiler in place (They had tried removing them). At 100km/h it's probably working, however the car is so incredibly composed and stable to begin with the spoiler is almost pointless.

    Now it does have one good point. It's a fantastic picnic table when your pulled over on the side of a road for a cuppa

    The spoiler it interesting. Check this out:



    See the little plastic windows in the spoiler (they should be clear). In my head they would act like air brakes by trapping air, however apparantly the car is nowhere near as stable at extreme speeds with them removed There must be an explanation for them being there .... Please explain

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  19. #19
    I might be slow... DRTDVL's Avatar
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    it's just creating more force with them in place... if the air was able to pass through there it wouldn't create as much force...

    think of it this way, are you able to scoop more water with your hand with the fingers spread or with a cup hand? the same princables apply to this except your "scooping" air, so to speak...

    if you hav a look at a person with a spoiler on the back of the car with no mid-support (the 95+ maxima's, mazda famila's (hatchbacks), some accords,etc...) you can see where the force has been acting on them as they are sagging under the constain stress over the years... newer spoilers are firmer and made of better matterials. i've followed my friends maxima and you can see the spoiler sag more and more as the speed increases.

    some spoilers are designed to decrease drag... i concure

  20. #20
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    i read somewhere, that spoilers offer neglegible downforce during normal speeds.


    case in point would be the audi tt. you boys might remember that with its recent update it copped a pissy lil spoiler on its arse to help with high speed stability... think it was in the order of the 240km/h stability for the krauts over in van tromp land!

    so yeah, it didnt carry some 747 wing etc, etc. it kind of gives you an idea of the type of spoilers that are on offer these days. almost all are aesthetic aids as opposed to any downforce aid.
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  21. #21
    I might be slow... DRTDVL's Avatar
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    i really depends on the design of the wing, and it's placement in air path that the car creates, what works on one car will not always work on anouther to the same extent

  22. #22
    1000+ Posts U Turn's Avatar
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    Quote Originally Posted by DRTDVL
    obviously they work better at speed as there is more force attacking on the spoiler therefore generating more force...
    The force is strong in this one, guide him we must. Sorry, getting caught up in the star wars hype.

    Anyhoo, that style of lip spoiler on the 307 (and in fact, most hatchbacks) is exactly that..a SPOILER. That is, it 'spoils' the flow of air that would otherwise wrap around the rear of the hatch, otherwise known as a 'vortex' or 'eddies' which causes lift and drag. That's right this turbulent vortex that forms at the rear of hatchbacks is an area of low pressure which results in a sucking force on the hatch i.e opposite to the direction of the travelling car. This is why if you're riding closely behind the back of a truck, it's very easy as the huge vortex is pulling you behind the truck. So what a 'spoiler' does is minimise that vortex so you get somewhat of a cleaner separation of airflow at the lip of the spoiler. So there you have it, most spoilers don't create any downforce whatsoever, at best they reduce lift caused by turbulence.

    A WING as found on racecars is different and that actually does create downforce because it functions as an upside down aeroplane wing i.e with a negative pressure differential between the bottom side and topside of the wing. With a wing you obviously do get added drag.

    Getting back to the 307, I don't think that lip spoiler is going to make any real difference to anything. Even if it is the right size and correct placement to actually do 'something', it certainly won't be adding any downforce, and at best and only at very high speeds will it be actually minimising any lift due to turbulence. However you can rest assurred that if it is working to minimise this turbulence, it won't be creating any extra drag and in fact minimising it.
    Take the long way home....

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    1000+ Posts PeterT's Avatar
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    Quote Originally Posted by 30780Y
    But is it all it does, the LOOKS??? Is there any idea other use???
    Somewhere to rest your coffee cup.....

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  24. #24
    Demannu-facturing! Demannu's Avatar
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    I read an article once on the Pikes Peak version of the 405 T16. That has MASSIVE spoilers on it, and apparently they have absolutely no effect until they are doing AT LEAST a hundred miles per hour (160kms/h).

    So as far as I'm concerned, anything else is just a handlebar for the shopping trolley.

    Note also that many supercars don't have spoilers. Their aerodynamics are far more subtly incorporated.
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  25. #25
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    Thinking back to the sixties-
    research on aerodynamics indicated that the teardrop was the most efficient shape, but too long. They discovered that if you cut the end off the teardrop square you could fool the airflow into thinking the rest was still there and nearly as efficient -refer Fiat 850 fastback and other performance cars of the period. Modern aerodynamics is much more advanced so subtle lips to aid separation are probably very efficient if done properly. These would be small, barely noticeable but could be very efficient if done for aerodynamics instead of style, but how many companies leave the engineers work alone when the sales and stylists get in on the act.

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