spoiler makes you go fatser ?

OK, I am 99.9% against this theory but a friend told me this and me not being 100% sure it was wrong decided to get proof before I just up and tell him hes dumb:biggrin:

ok, this is how it started.

I was just driving down the road and saw a car(I knew it was a pontiac cuz of lights) coming up on me, not gaining quickly, but i thought it was someone else, so I dropped to 2nd and took off. he obviously stomped it cuz he kept right up with me. then I still didnt know who it was so I would drop to the speed limit and then take off in 2nd to see if I could smokie this guy. but all 3 times it was about dead even. when we get to the parking lot he pulls up next to me and it is my friend who just bought a new car, its a 03 sunfire with the 2.2 ecotec. it is an automatic which sureprised me a auto domestic kept up with my dual cam swapped little hatch.

then on my way home I called this guy and told him "SUNFIRESA ARE QUICK! I just can barely stay ahead of an auto one. and he told me thats just because he was behind me, wqhich makes sense, I am taking most of his wind resistance. and I beleive it cuz in nascar you can get drafted. which I thought was cuz faster moving air has less pressure. so I fiugured, get behind someone, and thew air that goes around their car moves fastre so when you pass them you go through the fastre moving air and have less resistance. he says its cuz the air that goes behind you swirls and pushes them forward. I told him it sounded kinda wrong. then he said its like when you have a spoiler. I said downforce on a RWD, he told me thats a side benefit and that it is mostly to make your car faster cut the air swirls and pushes you forward. I just laughed in my head cuz it sounds insane, but he said he was SURE. now hen you blow out smoke and move you hand through it quickly, it does swirl, but never catches back up and hits the back of your hand until you stop your hand. It would be the same principlke with the air moving past a car correct?



please leave a response telling whos correct and "WHEN":tongue: i turn out right Ill send him the link.

Ahhh, an age old question, heres a bit I wrote a long time ago...

A spoiler can add drag (porsche 911 turbo, the 'whale tail' years).
A spoiler works on the Coanda effect. That is, air (or any gas or liquid) flows along like the surface it was on. Therefor, on a car, it goes DOWN the back, meeting the air from the bottom. This increses drag, but the air moving that way kinda (a little bit) decreases lift. Now, as far as I understand it, a spoiler causes the air to go up momentarily, flowing STRAIGT behind the car, not as much going down. This decreases drag. Now, the air UNDERNEATH the car has to come UP to the rear of the car, increasing the distance it has to travel, and therfor increasing speed and decreasing pressure going up (lift).
Now you see how it works. (they are in capitals just to highlight important stuff, not trying to make you look dumb. I have done that unintenially in the past )

That is a spoiler, the small 'lip' thing on the back of a car. It has nothing to do with aviation (actually, it does, but not for this reletively simple stuff)
A wing is a device that is an upside down airfoil. It decreases lift, but increases drag. If it is small enough, the drag will be slight. Sometimes it can actually decrease drag by letting the air out quicker and more efficiently. This all depends on a gazillion factors that are hard to understand.

Most magazines call small wings spoilers, which they are not.

Heres another example. On the 911 Turbo, it has a spoiler at first. Then it rises up into uninterupted air, in effect a wing. A true definition is hard to come by, as most people us the terms when they shouldn't.



So, basically, if done subtly, a small wing can decrease drag and make your car faster. However, essentially all wings on standard mass produced cars do not do anything for your car, except to slow you down. They are not shaped correctly to even add downforce, let alone reduce drag. They are dead weight, and add air resistance. On real sports cars, they are usually there for the downforce, so, they slow you down in a straight line, but, make the car able to round corners faster.

Oh, and that swirling behind the car, that is exactly what a spoiler or wing trys to eliminate. Because for every current pushing you forward, there are some sucking you back.

Found the article on spoilers. It is in the September 1998 Car and Driver, from pages 147-153. A very good article. Go read it now:icon16:

OK, so MOST spoilers dont help your cars speed and even the ones that do it isnt because the air swirls, turns around and then pushes you forward, correct?

Yes, correct. In fact, Ive never even heard of a wing increasing speed, their aeryodynamic drag more than overpowers their small 'streamlining' affect, but, that is their purpose.
A spolier does increase speed, pretty much all cars have one, its just a little rise at the end of the car.

But yes, you're correct:smile:

ok, well I showed the kid this and he thought you contradicted yourself where you said youve never heard of a spoiler increasing speed and then later in the post you said a spoiler does increase speed. but I read it as they are 2 different things like you also had explained(if I read it right)

but there was another guy there who tryed and acted like he knew everything which he doesnt. we watched a video of the races when we went to the track earlier that day and you couldnt barely hrear the cars and they were pretty far away when they took off cuz the film crew was at the furthest bleachers from the tree and he kept saying that it was obvioius that guy couldnt drive when he hadnt even tok off yet, and he was wrong on about all his guesses ogf the outcome of each race. and he agreed with this kid how the airl swirls back down towards the rear of your car. he started talking about how you never wanna lead for a long time in a race cuz you use lots more gas, so he does know something, but he probably only knows that cuz the announcers say it like at leats 20 times each race on TV.

but I tried tellimg him(using your explanation) that the spoiler kicks the air up past the car and the air from under the car hasa to travle further faster so it lowers the air pressure holding the car back. he told me it doesnt even matter if you have a spoiler its just cuz your car is angled up in the back and it kicks it up but it swirls back down and helps you go faster.

now I am not against that a properly designed wing can reduce drag and help you.

I a,m just trying to prove that it isnt cuz the air swirls and pushes you and it also doesnt go bhind the guy behingd you and push them, the reason why a guy can be faster behind someone is cuz the giuy in front is taking all the wind resistance and giing the guy in back alot less pressure to push through.

kk, heres a top of the line pic i made....not sure if I contradicted myself.
As you can see, its generally better to have a spoiler or wing rather then nothing.
And after looking at my drawings, ive reasoned that wings slow down cars because they already have spoilers. So the wing does reduce drag as much as the spoiler, but then adds drag by being up in the way. It does make for a bit less drag then a wing and spoilerless car. Depends on how big it is.

Also, having a wing or spoiler creates much less turbulent air behind the car, which makes it more stable at speed, which is always good.

The first pic didnt show the wing very well, heres a better example of the wing.

Ok...I really have nothing of value to add here, butttt....THOSE PICTURES ARE FREAKING HILARIOUS!!! HAHAHA! You need to learn to use the shape creation tools man!:biggrin: :biggrin: :biggrin: :spit:

Shape creation tools take away from the natural artistic-ness that permeates every aspect of my life.
In other words, Im far to lazy to make a pretty picture, ill just work along in paint, with a ball mouse that is dirty. And, meh, it works :smile:

ok, so a wing is good for down force, a spoiler is good for reducing drag and with nothing it is les stable at high speeds.

Here's a quick question for you, In Nascar, IMSA,NHRA,open wheel racers, why is so much emphasis put on the shape, size, and angle of the spoilers, anything over 150 mph will benefit from the downforce, by making the car more stable and in effect stuck to the track. This doesn't really apply to the front wheel drive cars. An air dam in the front may help by planting the front tires better but may also increase the frontal area to to a point where mph suffers, a rear wing is just for show on a front driver. Top Fuel funny cars and dragsters can create as much as 3,000 psi on the rear tires to keep 6,000 hp on the track. Loose the wing and it's gonna do a 1/4 mile burnout without the downforce.

Actually, a front air dam does nothing but improve a cars performance. It still has the same frontal area, only now, the air goes around the car, not into the front suspension, where is creates a lot of drag. So, it reduces drag, but increases front lift (bernoullis principle, fast air has lower pressure, more air over the top, must go faster, so, lower pressure), so, steps need to be taken to creat front downforce, which is not easy. An air dam is often shaped metal/plastic, which is just directing air up (every action has an equal and opposite reaciton, air goes up, pushes car down)

At high speed, you want your spoiler to give the best balance of low drag and downforce...more speed in the straigts for slower around corners, or slower top speed for faster around the twisties.

so now when i send him this link, basically, spoilers can make you go faster, and faster acceleration as well as tops speed if it is designed properly for less drag. but most spoilers that you put on your car like the ones you buy from body kit companies are more for looks, not EVERY spoiler makes you go faster. and it is NOT from the air swirling back down and pushing you forward.

A couple of people mentioned the 911 whale tail.

The top speed on a 911 (I'm talking Carrera 1's here, not the newer stuff) is indeed faster without the rear spoiler. However, at speeds above 220km/h (140mph), the shape of the 911 Coupe's roofline (not so much the Targa and Convertible), causes lift, much like a wing does. This lift has a tremendous amount of influence, especially on the rear axle. At higher speeds, the rear end gets very light, which isn't much of a problem while driving in a straight line, but rapidly becomes a problem when a curve comes along. The light rear end causes a tremendous amount of oversteer when one gives even a slight amount of steering input at high speeds. (I don't mean "oversteer" as in a drift, but oversteer as in a dramatic shift in the rear end to the left or to the right.) It can really catch you off guard when you're not used to it, because even at slightly slower speeds (say 200km/h) the car handles very predictably again.

Aside from reducing turbulence behind and around the car, reducing lift and providing downforce, some spoilers/wings/tails are also added to provide straight line stability (on the sides of the top-fuel wing, Plymouth Superbird). These large vertical surfaces are great for keeping the car going in a straight line at high speed, until you hit a strong crosswind.

Another thing to note is that all these effects that wings have are only noticable at high speed.

you also mentiond in your post something about this guy trying to draft you like in NASCAR. Well rember NASCAR cars are bigger than your car so they push more air out infront of them also they are going almost 200 MPH. going that fast and moving that much air out of the way thoes cars almost create a vacume behind them pulling the other car. Aero dynamcs also don't play a real big role in your cars rate of acceraltion. it comes into factor at about 80-100 MPH depending on your car i highly doubt that guy was drafting you

Andy

ok. well, he was just trying to tel me he kept up much easier cuz he was behind me which i beleive cuz i can almost keep up with my friends mid 15 second teg with my mid 16 second hatch when im behind him but side by side it is much worse for me, but he was trying to tell me that a spoiler makes you accelerate faster because the air swirls around and pushes you forwards. and that sounds kinda weird cuz if it was true every car maker would put one on all their cars so that they were faster IMO

get one if you like the way it looks...stay away from the two foot tall wing though...

I dont want one, I have a hatch now and think they look kinda :uhoh: on it, and my next cra is an integra and i used to have one and I liked the spoilerless look more than thje ones buzzin around wiht wings. they do look nice though, just cleaner wihtout it.

maybe Ill check the link out sometime but you do realize my last post in this thread was...

almost..

TWO years ago.

didn't even notice