c32b

um...but just like the angle of attack on the wing, a lip like the apr one might press the nose of the car down. just wondering if there were tests on these.

i saw a review of an amuse lip n wing on the new r35 gtr.

blkblks2k

Just put it on and test it yourself. Ever driver is different find what works for you.

INTJ

ddess

I bought a replica cf wing and spare trunk, not sure of the brand it was a knock off of. It was from Coalkitty, he might have some info on the make.

But I have a stock 06 and that wing combo lowered my lap times at SOWS by .750. I definitely noticed the added stability in medium to high speed turns. I also now developed under-steer in certain turns.

I hope this helps.

Antonov

Not sure about streets, but I can def see where it would nice @ button

JackOlsen

I did some research on this for my car (not an S2000), and designed and built a wing and tested it pretty extensively. If you have a video camera and a data logger with some free inputs, it's possible to do a lot of testing without any significant cost (although driving down the 405 with dozens of wool tufts taped to your car might bring some personal cost, in terms of personal embarrassment).

At most tracks, the benefits of a wing and a front spoiler are going to be minimal -- probably in the neighborhood of a half second or so, speaking very generally. The easiest way to guess where you'll see the benefit is to look for corners where you're sustaining 80 mph or more through the corner, where you're also not flat on the gas -- in other words, if your speed isn't limited by sliding sideways, then the aero is probably not going to help, and possibly hurt (with its increase in drag).

Balancing aero's effects on your front and rear axles is important. If your car is beautifully balanced now, and all you do is add a wing, you're going to have less-beautiful balance in high speed corners. People tend to think of the front spoiler as only changing the lift/downforce on the front axle. This is a mistake. A spoiler reduces the amount of air getting underneath the car, and improves lift/downforce on both axles, although not equally. A front splitter (the horizontal piece) will have most of its effect on the front axle and a rear wing will have most of its effect on the rear axle. Too much rear wing can actually cause a cantilever effect, where the front end is lifted slightly by the rear coming down.

I'm not an aerodynamicist, but I read a couple of books and talked to some experts when I put my aero pieces together. I learned that the position of the wing makes a huge difference on how it works. Getting it into a clean airflow is better, of course, but it would be a mistake to say that getting the thing up above the height of the front windshield will accomplish that. Your windshield pushes air up as it moves and it keeps going up well above the height of the windshield. The air also gets pulled down as a low pressure area is formed behind the car. My wing is on long extensions, up above the hight of my roof, but the air is moving down at about an 11-degree angle where I've positioned it. To look at it, most people would probably guess that it's high enough to be seeing airflow that's parallel with the road.

I tested airflow direction and turbulent/clean areas on the rear half of my car with wool tufts. With the same technique, I was also able to see how well the air was adhering to the underside of the wing (where most of the really important work gets done). This was helpful in looking at what effects changing the angle of attack of the wing meant. There are angles where wings tend to function best, but those angles are relative to airflow, not to the ground. And while adhesion on the underside of the wing is important, some separation can take place while the wing's performance is still improving -- a wing stalls when the separation is so widespread that the wing stops working.

A really useful trick I came up with was getting a pair of ride height sensors ($5 each on Ebay) from a late-nineties Lincoln Continental's air suspension. I was able to just zip-tie them to my front and rear suspension, and then run the outputs to my DL1 data logger -- it let me see the actual changes in ride height, at specific speeds, as I switched different wings and also different wing, spoiler, and splitter settings. I did fixed-speed straight-line tests on a stretch of road out past Mojave, and then also looked at ride height changes on a track with enough fast corners so that aero makes a 2+ second difference: the big track at Willow Springs. On both the fixed-speed straight-line runs and the test laps, I could detect changes in ride height from as little as 4 degree changes in the angle of the wing.

One warning that should come with the move from a sillytown poseur wing to something that's actually doing aero work is this: if a wing is generating 400 pounds of downforce at 130 mph, you'd better have very strong struts and a very strong mounting scheme for that wing. The 72-inch wing I made out of roofing aluminum and structural adhesive only weighed 4.5 pounds when it was done -- so I was understandably anxious when I tested it with 350 pounds worth of sand bags. It held, though. Most magazine-ad wings aren't doing anything meaningful for downforce, so you can rivet them to the trunk and be fine. All they are is a little bit of drag and maybe a psych-up for the driver. But if you actually put on a wing that works, I'd recommend load testing it like I did with mine before you go out to Willow and have it fly off of the back of your car and into the front of somebody else's.

mikegarrison

Just a quibble, Jack. This is the most sensitive part of the wing, yes. In that sense, it is the most important part. But it's not quite right to say that this is "where most of the work gets done". What is important is the total pressure difference from top to bottom, not the local pressure in any one place.

JackOlsen

You're right. You need both sides. I said it because my layman's understanding of a wing, early on, was so completely wrong -- thinking it was the upper side that basically collided with the oncoming air and pushed the car down as it deflected the air upward. I still wouldn't claim to be anything more than a layman, but the tuft photography I did on the wing showed that the underside was where I needed to do the most work to manage the airflow. To me, it was eye-opening.

nichigo

wow that's good info jack

Would you mind elaborating on the design of your wing and how it's effective?

mikegarrison

The issue is that the underside of the wing (or top side on an airplane -- lets call it the "suction side") has what is known as an "adverse pressure gradient". What that means is that only the momentum of the air going past the wing is keeping it attached to the curvature. As it slows down it loses energy. As it loses energy, it eventually peels away from the wing surface. We call that "separating". On the other side of the wing ("pressure side"), there is no adverse pressure gradient, and you don't need to worry about separation.

So the suction side is the most critical to get just right, or else your wing is going to not perform well. But it would be incorrect to think that means it "does all the work". Kind of like your driveshaft. It it breaks, your car is going nowhere. But that doesn't mean it is your driveshaft that does all the work in making your car go forward.