I have searched vigorously regarding downforce affects of the feed type II wing (Not the GT wing) and have found marginal information regarding how much downforce the wing produces in comparison to other wings.

Like most of us FD owners who do drive our cars on the street, a GT wing is not an option due to functionality, looks, police attention etc. I do track my FD often and will find use for more downforce.

There is plenty of information regarding the 99spec wing and its aerodynamic affects, so it would make sense to have comparison of both 99spec and the FEED wing since they both fall under the "streetable & functional wing" option for our FD's. I havn't read up much on other "stylish wings" such as the duck tail spoiler or RB type II. I personally like the FEED wing more looks wise, but would like to know if it actually works before I buy it.

SO, could anyone here post their data, experience and knowledge about the FEED type II wing as far as functionality goes? For those that have/had it, did they actually feel adequate handling affects at higher speeds? How adjustable is it? My guess would be that it produces similar downforce as the 99spec or maybe less.

It would also be interesting to also have comparisons of 99spec/Feed vs GT wings. Clearly GT wings will produce more downforce but after watching this..
http://www.youtube.com/watch?v=u6_MU...layer_embedded

It seems the 99spec isnt far off from the GT style wings. my .002

 

the only difference i can see from the 99spec and the GT wing is that the GT wing sits higher so more incoming air can move over it in relation to its angle of attack.

most GT wings ive seen produce as much as 400lbs of downforce a full angle, while the 99spec has been said to make 120lbs at max

 

Cool video!

 

I am also interested in the 99spec vs feed II regarding downforce production.

 

It would be also interested how the 99 spec wing preformes when it is lowered/angled (to produced more downforce).... on that video it is placed in horizontal position (lowest downforce).

 

hoping for some input from guys who own the Feed wing.

 

I definitely felt a difference over the stock '93 touring wing. The FEED Type 2 was a little over the top for me with the carbon fiber, so I got rid of it. I swear to God, tho, coming into turns 5 and 6 at Laguna Seca, I coulda sworn I felt the rear end plant itself better than it did with the stock wing. More than I realized when I put the FEED one up for sale.

1993 touring, Stock Swaybars, Zeal Function coilovers, Toyo R1Rs, Aerofiber FEED knock off. I've never had a 99 spec wing.

 

wait...but I thought wings don't produce downforce until 100+ mph? At least that's what someone tried to convince me. Blah blah aero doesn't matter til 130mph I think was what someone was saying. In the vid those corners were taken at only 60-70mph.

 

It depends on the wing and angle of attack. AutoX pros use large wings with high angles of attack to generate downforce at low speeds.

 

Wings and aero work at any speed where air is moving really. When I used to race R/C cars, I was always amazed at how much difference it made on a little thing going 10-40 mph.

 

Hmm interesting. So according to the video, the 99 spec wing (presumably at max angle), does provide quite a bit of stability to the rear? If so that might put me over the edge to actually put my 99 wing on the car.

 

there is an SAE paper on the 99 FD's and they list the downforce for each wing position.

there is a tradeoff though, on the 99 spec car, the more downforce you have in the rear, the more lift you get in the front

 

I don't believe.

 

go find the paper.

 

I have the same feed replica. It's nice to know that it's doing enough that you can feel the difference.

Edit: Forgot to ask, were you at max angle?

 

Based on weight transfer alone, yes it's true.

If you want to add downforce without affecting balance of grip front/back, you have to add it at both ends.

On some vehicles, having a taller spoiler (all other things being equal), increases downforce. However the FD has a good aero design and the air is traveling almost as fast the whole way along the hatch. So it should make a minimal difference. Said another way, the cabin of the car does not break the wind appreciably as it approaches the rear spoiler.

David

 

Its true I have played plenty with wings in Star Mazda, Formula Renault, Formula 3, and Le Mans LMP2 if you add to the rear you will take away from the front. quite often in racing you may just take away front grip to gain rear grip. I doubt it would be a substantial ratio in a RX7 though.
As far as minimum speed goes the slower the corner and the harder you accelerate the less aero grip matters. A lot of race car guys say under 100mph it doesn't matter and I know driving with broken wings you don't notice the loss in 2nd gear corners but most formula cars have flat bottoms with diffusers that create downforce rather than an FD that creates turbulence and lift. If you are trying to gain rear grip in slow speed corners I would look for mechanical grip.

 

Yes, The angle was adjusted all the way up at Laguna Seca.

IMO, a little front-end lift isn't that big of a deal on a car with the engine in front. If this were the Elise or 914 club, I'd be singing a different tune.

 

I have the 99' wing and that was flat. At the max downward angle there is a noticeable arch in the wing where it follows the body.

I can tell you in the down position coasting from 60-30 there is substantial aerobraking going on, as compared with level. I'm surprised it had that much of an effect in that position. I wonder how much is due to weight, because it isn't a light piece.

 

I'd LOVE to know that the FEED Type II wing provided significant downforce, but I have to say I'd be surprised if it did. Mostly because I have one (aerofiber, unmounted), and it doesn't seem like the structure of it would carry much weight. If it was actually producing, say, 100 lbs of downforce, that means you'd be able to stack 100 lbs of weight on it, and I haven't tried, but it seems like I could collapse it if I leaned on it.

 

Also, for a guy like me to say there's a difference...Lets just say I didn't hit turn 6 at 100mph with no wing, then at 100mph with the FEED wing, then the stockie, etc.

Its easy for me to think I felt a difference, but in reality, it's kinda like a butt dyno. Between the coilover suspension, bracing, stiff bushings, R-compounds, etc on my car, well...Yeah. My info is sketchy at best.

If ya asked me, No wing LOOKS best.

 

I'm no aero engineer but I can do a load/force diagram ...

A "wing" produces two forces at orthogonal angles - lift and drag. On a car wing the lift force vector is downward, the drag force vector is rearward. The location of the wing relative to the wheels of the car create moment arms, turning those linear forces into moment forces. Ideally you want a rear wing located directly over the rear axles and as low as possible while still in effective airflow. If you mount a wing really high and/or really far back on the car it will increase downforce at the rear but can also unload the front suspension. I wouldn't say it creates lift at the front, but the effect is the same as when you see a pickup truck with a bedful of dirt or towing a trailer with too much tongue weight and the nose of the truck is in the air because the front suspension has been unloaded.

As others have said, you have to balance both the front and rear when working with downforce.

 

I'm getting a roof mounted wing, like a sprint car

 

I have the feed wing and you can definitely feel the difference as you change the angle. I usually keep it near the middle since my car is usually street driven. However at the lowest angle, you can really feel the back is lighter at speed around corners. At the max angle, there is a lot of drag, you can't see out the rear mirror but the back end sticks like glue.

As for front end lift, I have the RE Amemiya front bumper with carbon undertray and rear diffuser. The front undertray goes all the way back to the subframe connectors. Its one complete piece.

The car is about 1.5-2 inches high at the lowest point.

The needle been near burried (on the track) and the car is stable as hell.

The FEED spoiler on my FD is authentic but I believe some of the copies are of good quality. I've seen the aerofiber feed copy (he offered me a ton for my original to make a mold - I didn't accept) and its very close to the original feed.

 

Howard Coleman runs a FEED II replica wing, I'm surprised he hasn't commented.