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Thread: When does a spoiler become useful?

  1. #1
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    Default When does a spoiler become useful?

    When would you sa a spoiler becomes useful? How fast do you hafta be going? and what height of spoiler do you think is the best?

    Im thinkin a low profile wing is nice, not those over sized pizza trays but thats my opinion heh.

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    It's the angle of the wing that creates downforce. At what speed depends on the size of the wing and the angle it's set at.

    Are you looking at a wing for a track car? They don't do much on the street (assuming you're driving within legal limits).
    Originally posted by SEANBANERJEE
    I have gone above and beyond what I should rightfully have to do to protect my good name

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    when the pros use aluminum wings, they spend tons of time in the wind tunnel testing, tuning, adjusting the wing for a specific amount of downforce at a certain speed for track use. this level of precision is nearly impossible to achieve on a street car, and wings generally dont affect the car much until over 100kmh.

    make no mistake, spoilers on street cars are more for looks than anything else. nobody really buys a spoiler as a performance mod..

    and if u wana get down to it, they dont actually make downforce, they just deflect air to prevent underbody turbulence.

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    When does the speed limiter on your car kick in? You should notice a difference at about this speed.

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    Alrighty,

    Wings on FWD cars:

    Misconception: It is effective at moderate speed.

    The wing wont keep your front tight on the ground in any real difference whatsoever. It creates downforce over the rear wheels so that in a RWD car it provides better traction/stability.! Any downforce provided on the front wheels is far exceeded by the force applied to the rear of the vehicle.

    Unless the FWD car has a mad front spoiler like an indy F1 car or huge tunnels under the car or something creating the Bernoulli effect, traction provided by downforce will not be extensive.

    Here, I'll get a bit more tehnical for you just so we can all fall in love with science.:

    We can start off with the theroy that The Aerodynamic efficiency of a car is determined by its Coefficient of Drag, I will refer to that as (Cd).

    The Coefficient of drag is independent of area, it simply reflects the influence to aerodynamic drag on the shape of object.

    For example, Theoretically a circular flat plate has Cd 1.0, but after adding the turbulence effect around its edge, its CD becomes nearer to 1.2.

    For those who care, the most aerodynamic efficient shape is a water drop, whose Cd is 0.05. However, we dont all run out and build a everyday street car in this shape so a typical modern car is around 0.30 (Cd).

    Actual drag is proportional to the drag coefficient, frontal area and the square of vehicle speed.

    Hence a car going at 80 mph has 4 times the drag of a car traveling at 40 mph.

    This influences the top speed. If a company needed to raise the top speed of Car with 390hp and a Cd of 0.36 from 180 mph to 200 mph without altering its shape, it would need to raise its power from 390 hp to about 535 hp!

    or the company can blow far less time and money on engine and drivetrain improvements and use it in the wind tunnel, advancing its Aerodynamics. All the car manufacturer would have to do is decrease its Cd from 0.36 to 0.29. This would achieve the same result without having to put in a beast of a motor.


    And Lift, just so we can get everything on the table:

    Like I mentioned about drag, lift is proportional to area (but total surface area rather than just frontal area, the square of vehicle speed and Lift Coefficient, and so I'm going to make that easy and call it (Cl), which is determined by the shape.

    At high speed, lift may be increased to such an extent that the car becomes very unstable. Which is really not what you want to happen now is it.

    Witness Mercedes Group B Racers doing the loop de loop at Le Mans to see what becomes its obvious conclusion. We've all see the video of the Mercedes that does the nice lift off and backflip into the trees at the LeMans a few years back.

    At more mundane speed Lift is particularly serious at the rear, since a low pressure area exists around the rear window, kinda like a waterfall churn. If the rear lift is not adequately countered, the rear wheels will not provide adequate grip and the car will go into Over steering mode, just the opposite of what is required for good Stability. This is why in most cases huge wings on a car dont make much diff at speeds less than 160km/h, or 100mph for the americans on the forum.

    Even worse, a Fastback design is particularly bad in this aspect, because it has a very big surface area in contact with air flow. Porsche introduced the big Whale Tales to nullify this.

    Paradoxically It would seem that achieving good drag and low lift are mutually exclusive, Its all a big trade off, Automotive race teams do it all the time trading top speed off against cornering grip. There are however are some solutions to help achieve a good balance of both, its just a matter of R&D to see what works best for your car.

    Okay, so now we are all filled in on how Lift and drag works.

    Unless the fwd car has a wild body kit providing some downward force to the front wheels, its not much use to apply a massive spoiler, or any spoiler for that matter.

    When it comes to cornering at high speeds the spoiler can be effective on a FWD car, keeping the ass end planted better and stabilizing an oversteer situation and having the car spin out. This is of course only really effective at speeds greater than 1 and a half times that of deerfoot.

    HTH.

    never thought I would use any of that junk I learned in Physics30AP

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    wow, u must have a lot of free time on your hands j/k

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    LOL hahahaha, u obviously know ur shit..... or it's all a bunch or shit..... either way... u have alot of time on ur hands!

    :tongue:

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    haha only one thing to add to bennys post...most bodykits actually make a car less aerodynamic and serve no performance functions.

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    no way man...my car felt so much more twitchy after my spoiler fell off

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    right from rest

    A good solid rear wing or spoiler can make a nice push bar.

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    on my peeon i felt a small difference on how the car felt at high speeds, once i got my airdam on...It used to feel like the car was almost floating once i hit 150...not saying they're really usefull, and yes most of them are completely useles...just happened that the peeon liked it and it helped a bit...

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