We all know that the OEM spoilers rear wings provide little to no aerodynamic downforce, but with an adjustable GT wing or spoiler, at what speed and angle of attack does it actually provide down-force and drag? Is it 80mph where angular adjustments can provide extra grip? It seems the larger the wing surface area is, the sooner its effects can be felt (Look at Outlaw sprint cars).

What I’m trying to say is….what is the optimum angle at the lowest speed where the effects of an aerodynamic wing improve handling and grip without causing extra drag, and what is the overall best setting for street/highway use? Or is it really impossible to get some functionality out of these aero devices unless you're on the track?

 

IMO you don't need a wing unless you race I think most people get them strictly for looks. Most of the large aftermarket wings would adversely affect handling at higher speeds.

 

For the looks we can all agree on, and I can see where you would need some front down-force to prevent it from getting light with a rear wing at very high speeds. Ever put your hand out the window at 80-90mph?

 

Wings don't do a damn thing untill you are at very high speeds, somewhere around 150+. Unless you plan on racing at those speeds I wouldn't worry about it.

 

Really? Then why don't Stock Car crews just take them off at the short-tracks when they don't ever corner over 90mph???

I wonder if anyone is going to reply to this post who knows what they are talking about. It's a good question.

 

well, if it's generating downforce, it's also generating drag, so the combination of added downforce without added drag doesn't exist.

secondly, the wing adds *rear* downforce, therefore it will help oversteer; some suspension tuning will do the same thing (especially at highway speeds), hell, you can change tire pressures to help with that if you really think it's necessary.

What I'm getting at is that a wing will do you no good on the highway for anything other than reducing your gas milage.

 

Toadman, the problem is the angle would vary for each individual wing and your desired characteristics. BTW, how do you know the OEM wing and spoiler do not add downforce. They lower the Cd from 0.29 to 0.31.

BTW, contrary to popular opinion, you can add downforce without raising the Cd. In fact, the new Infiniti G35 coming out has an aero package that reduces rear lift AND lowers the Cd from 0.27 to 0.26!

 

the gt wings....shows the laptime improvements on a race course...there is no doubt about it...it can be seconds per lap...which is HUGE...

 

The OEM spoiler adds downforce at the front and hardly affects Drag
the OEM wing adds loads of drag and reduces Lift slightly (see the 200mph fd thread) the wing is mostly responsible for RAISING the Cd from 0.29 to 0.31. A properly shaped wing can be effective a speeds as low as 20mph BUT a wing that works at low speed will just creat loads of drag at high speed. Look at the diff between speedway wings and road race wings on CART cars.

 

As somebody else has posted, you can't have downforce and no drag added on. In a perfect world this would be ideal but unfortunately.....

The OEM "wings" help reduce lift at elevated speeds. You can actually feel the difference if you get to ride in a base RX-7 with no wings and ones with wings. The wings are effective as low as 70km/h I believe.....

Which means, at the speeds that we travel here in Ontario, having wings is very effective in keeping the car on the ground. We usually cruise at about 140km/h up here. With the "fast" lane occasionally reaching speeds as high as 180km/h. And that's with a normal Accord or Camry! Little do these people know that at those speeds their cars are basically floating on a cusion of air and if anything "jumps" in front of them there's no way their going to have brakes because their tires are basically not on the ground.

The 99 spec front lip is a bit more effective than the previous lip. And having a 99 spec rear wing would be beneficial I personally think having the previous OEM rear wing is enough. I hate it when they start to put those "rice" parts on cars.

I wouldn't be so quick to point out that our OEM wings don't help reduce aero lift.....

Later,

 

Agreed, and I know we are really splitting hairs here for closed-course racing. And I'm not smacking on the OEM rear wing in the least, although the surface area is smaller, rounded and there is no upturned lip or adjustability to speak of. Just looking for a balance where functionality may come into play at highway speeds for those considering an adjustable wing, and I've never seen a post addressing this with the FD and the velocity it can achieve.

/me wonders if the Mitsu VR4 was truly functional, let alone 911

Any aerodynamics or open-wheel racing gurus?

 

My driving school instructor at Lime Rock have the GTC wing on his FD. He re-adjusted his wing to the steepest angle hoping to get more downfoce on his rear so he can fly down, maxed out on the last turn going downhill to the main straight. Well, he came back after a couple of laps and he said the rear end bottom out in the turn. In his case, just a bit too much. I would say he is doing about 80 in the turn, so the wing definitely work even with moderate speed.

We also discussed about the effectiveness of the OEM wing. The trunk area creates a low pressure area sucking air from the roof as well as the side of the car. The way the wing angles actually smooths the air and creates downforce. Obviously not as direct as the GTC wing would.

Both wings works, with the GTC being more efficient. Personally I am more concern with aftermarket ones since I highly doubt they run through the wind tunnel and test it like Mazda did.

By the way, there was a local accident with a riced out Integra with the shogun wing pulling over 120mph, and the darn wing pull the whole hatch out....I guess he's making up force instead of down.

 

Lost time,

There is a huge difference between the design of stock cars in comparison to the style wing that is being discussed in this topic. In order to take advantage fully of a gt style wing you must be going at high rates of speed. Wings for the street are purely for looks and are never needed for any kind of downforce/drag purposes, and if they do make a difference it is so slight you will never notice, just ask any serious racer. I say forget the gt-style wing and put some suspension on the car.

 

Aerodynamics start to affect the general dynamics of the car at 45 mph. At 70+ mph, the effect can really make a difference. My friend that used to build solar car told me this. As you know, solar car has to be really aerodynamic and efficient.

A rear SPOILER can help to channel the wind flow and minimize turbulance. This can reduce your Cd. A rear WING adds lots of downforce (a couple hundred lbs at 70 mph). It also makes the car less aerodynamic. The front spoiler increase your Cd bc it adds frontal cross section area. However, the front spoiler reduces the wind under the car which makes the car more stable at high speed.

No it does not need 150 mph to make downforce. If that's true, all Indy car racing on street circuit don't need wings then.

 

I never said the car had to go 150 to make downforce. Yes they might make some drag and downforce at 45mph, but they are not efficient and serve no purpose what so ever.

 

While on this topic, I thought you guys might want to see this:


Those are aftermarket wheels causing all that turbulance, and it's an aftermarket wing (Racingbeat?).

 

'Wings don't do a damn thing untill you are at very high speeds, somewhere around 150+. '

'I never said the car had to go 150 to make downforce.'

I think you just contradicted yourself! BTW, I still say that you don't need 150 mph to make downforce that's affects the dynamics of the car.

 

Cd and lift numbers for the FD are available here:
http://www.scuderiaciriani.com/rx7/body.html#SPO

Aerodynamic Coefficients of (1993-)1995 Mazda RX-7

Baseline RX-7 RX-7 R2(R1)
Cd, drag coeff. 0.29 0.31
Clf, lift coeff FRONT 0.16 0.10
Clf, lift coeff REAR 0.08 0.08

This leads me to believe that the front lip spoiler reduces lift in front, and that the stock (U.S. model) rear wing is nothing but eye candy. I have since added a lip spoiler to my base model.

A propely designed wing can surely help in back, too. Several of the FDs that are campaigned by M2 and other tuners have wings because the shops tried them and they worked -- lower lap times.

Wings can make a difference at low speeds. If you follow the Formula SAE competition, there has been a trend toward adding big wings to generate downforce. Those cars drive at speeds almost exclusively under 70 MPH. My brother was on the UofMichigan team that had the first big wing, and it provided a bunch of downforce as low as 35 MPH. The recent winning Cal Poly Pomona car had big wings on it, too. If they didn't work, these teams wouldn't use them or at least they wouldn't win.

-Max

 

Not true. Guess you've never heard of ground effects

 

Should a rear wing have an airfoil cross-section? Or just a symetric one, with the wing in a position with the rear edge slightly up?
It would seem to me the airfoil would be best, but the toy wings I've seen don't seem to have that. I'm thinking up-side-down airplane wing, flat on top, curved part down.

-Les

 

Les, your intuition is right -- you want a "wing" turned upside down. A symmetrical wing would not do much more than add drag. A true wing works on the same principles as an airplane wing.

 

go here to see the numbers on the 99spec front lip and rear wing

http://www.rx7.net.nz/newrx7.htm

 

Here's a quote from Garry Waldon, who drove the SP version of the FD that won at Bathurst. ".

'We tested the rear spoiler in three different guises out here (Eastern Creek),' informed Garry Waldon: no spoiler at all, the factory spoiler and the high mount version - which won favour. 'The small standard spoiler proved it was faster around Eastern Creek than no spoiler at all but the high-mount was around six-to-seven-tenths quicker again.' The notorious Turn One sweeper is where the rear spoiler benefits most, raising the car's corner speed 5km/h 'You can really feel the increased downforce around here," added Waldon who hustled through the sweeper during the race consistently over 200 km/h.
There's a piccy here <img>http://homepages.ihug.com.au/~markinoz/sp1b.jpg</img>

 

Actually Ground effects do CAUSE DRAG (but less than a large wing producing the same downforce) Race cars use ground effect tunnels because of the HUGE AREA available under the car for producing downforce can produce LOTS of it with relitivly small drag penaltys

 

I have the CF C-west GT wing and sure that C-west stuff is tested in the wind tunnel and that is why they use it on their race cars. I know that it is true that most have them on just for looks as far as by part goes I have it cause I loves the quality unlike most other GT wing on the market and it completes my whole look front and back and cause I know that sometimes I do high speeds and it wouldn't hurt to have the wing on, I also know that it works cause I do a couple of 130+ and when compares when I have the stock wing on, I can see a diffference at those speeds and I also positive that it would works at low speeds also or around corners and keep your stable. So if you are going to get a GT wing or any wing on the market make sure it is functional and wind tunnel tested to ensure you didn't get it and the damm thing fall off your car like those cheaply made wing and that lots of it out there and not functional just for looks. Have you ever seen those options video almost all Japanese cars are using a GT wing or some type of a wing on their cars especially at a circuit racing low or high speeds and it is like a tradition that they have to have a wing on their car from my point of view.