prew

iTrader: (9)

I was wondering if any of the big GT wings people have on their cars actually help out on the track. I would think the mazdaspeed is a good one but its not adjustable so am unsure. So does anyone know which ones provide downforce and which are just for show?

Air-Rex

Mazdaspeed GTC, and R-spec are adjustable
eric

turboand

hmm...going off:
ALL the GT cars that run them
ALL the LeMans cars that run them
ALL the Touring cars that run them
ALL the F1 cars (you seen one of them 'handle' when it gets smashed off!!!)


I'd have to say its all for looks really!!!!!!!!hehehehe!!!!!!!!!!!!

...Although, many of the cheap wings (ahem ebay) dont look to have even seen a wind tunnel, most of the quality japanese ones C-west/cusco/top secret/gp sports etc. all have genuine aerodynamically correct sections which are very effective in the 70mph-150mph area and are very similar sections to light aircraft eg. cessna (upside down obviously!)

855m0n0

iTrader: (1)

I use the Mazdaspeed GTC wing. I works for landspeed racing (which is why it is on the car). It has supposidly been wind tunnel tested. I personally think it looks aweful, but that is me. Above 150mph it is very noticeable. Below 100mph it is just a way to not see the flashing blue lights behind me...

Sickass7

They are for show pretty much, plain and simple. Especially on those riced out hondas that take 5 minutes to get to 100 mph.

turboand

Hmmm......tell Michael Schumacker that it's 'for show'........

...or try 150mph in a rex without one......ouch......

Sickass7

we aren't talking about actual race cars here moron. For most applications for us people who aren't on an F1 racing team, the use of wings would be negligible. Most people don't drive alot over 150 mph, and if they do I hope that they do it on a track. Maybe across the "pond" they allow you to drive that fast without being thrown in the slammer, and I hadn't heard of anywhere that you could besides the autobahn.

cloead

ive gone 160 in mine.. no big rice wing =/

prew

iTrader: (9)

I am well aware that race cars use gt wings. My original post was asking if any of the gt wings made for the fd have any positive affect on aero, not if gt wings in general provide downforce.

Also like others said the car has no problem going over 150mph without one.

FDNewbie

iTrader: (10)

I think practically ALL spoilers have A positive effect of generating downforce. But the issue comes when you're trying to determine just how much downforce they can generate (some spoilers are better designed than others) and which ones are aerodyamic, ie minimize drag as well.

A lot of the GT cars simply don't care much about drag because they're looking for handling, not top speed. And they got plenty of hp anyways. So it really comes down to what you want and are looking for. Very very few spoilers have been wind tunnel tested to generate downforce AND reduce drag - namely the stock R spoiler and the Mazdaspeed spoilers.

Well keep in mind a lot of that has to do with other factors such as what tires you're running (better traction), if you're on the stock suspension or not, if you have a stock or aftermarket bumper, sideskirts, a front lip, etc. AND, the stock body was wind tunnel tested up to 159mph IIRC. That's with and w/o a spoiler. The Yamaguchi book states that the shape of the rear end was designed to generate downforce, much like a spoiler, even without a spoiler on it. It's when you go ABOVE the speeds the car was designed for that you really need to enlist outside help. My friends and I did a quick 150+ run/race on the way back from Rotary Revolution last year, and 2 or 3 other FDs pretty much pulled back once we hit 150ish because they felt squirrely. I pushed on to 165, and she felt 100% ROCK SOLID, firmly planted. BUT, my top speed suffered greatly due to the large GT spoiler I run - it took like 10 seconds to go from 160 to 165...

dark phoenix

https://www.rx7club.com/showthread.p...t=aerodynamics

MakoDHardie

Ramy, you don't have a spoiler, you have a big rack of two long fins with funky teeth hanging off the ends. The tech design of a spoiler as we know them revolves around the Bernoulli Principle and requires the shape of the wing face to be asymmetrical from top to bottom so that the bottom is rounded and the top is cut straight and significantly shorter than the bottom side so that the airflow underneath the surface is forced quicker than that over top when it splits. Faster fluid speed on one side of the object generates a pressure difference and force is generated. Without the real wing design incorporated into the piece, the only downforce generated is the cause of aiming flat surfaces downward and relying on a skegging effect that is usually only effective in hydrodynamics. Aiming a flat surface down also causes a huge amount of drag when the exposed surface hits the moving air. That's why real wing shapes are necessary to minimize drag AND produce downforce at the same time.

The reason you car feels "ROCK SOLID" at those speeds is because you have enough body work and canards installed to make the car squat and compress the stock suspension at those speeds. I bet that if you traded your wing for a set of coilovers, you'd find the result much more effective. Especially if you traded it for a decently engineered wing. Beyond that, you'd also be able to get rid of the 10 second 160-165 acceleration time if you didn't have all that unnecessary drag from the wing and extra canards (rear) and put some money into your engine for once. Otherwise, you're better off for performance with the stock body plus a lip and diffuser.

turboand

posting as a 'moron' here (I'm sure YOU never go above the designated speed limit sir)...
Having had various forays into the 160+mph area in different makes/models of car, stock aero AND modified aero, a well designed aftermarket rear wing gives MUCH more stability. Im NOT saying the standard shaped rx7 and standard wing are useless, but stating that modified aero can and will assist control at speeds.

in a straight line at 140mph, the standard shaped car and wing will be very acceptable, a good comprimise between downforce and drag. At 160mph, it is very possible that the airflow over the car will actually completely miss the low mounted wing, hence raising the wing up into the airflow will make it able to contribute to the aero effects on the car at low AND high speeds.

the aero section of the standard wing is poor, and the 'hooped' design of it will reduce the effective width of it to around 70cm-ish, so a wider/straighter one will be more effective at low AND high speeds. Back to the section...anyone involved with aircraft will know of the various 'standardised' wing sections, these are calculated and tested designs for aero sections which can virtually be picked depending on speed and lift/downforce required... the rounded off asthetically pleasing showroom happy original equipment spoiler AINT one of them, not that its useless but you wont see it on a boeing.

So....(sorry to DRAG on;-)) if you can put up with the idea of running a high mounted, wide, 'GT' style wing and want MUCH IMPROVED stability at higher speeds (over 70mph) then theyre great. (some run a section suitable for around 100mph+ but have adjustable angle of attack to lower the effective speed to around 70mph) Cusco have 3 sections available depending on what speed you require more downforce at.

BUT for people who stay to the speed limit, never go on a track/airfield, and the once or twice they head up to those speeds not giving themselves enough experience or comparison to pass judgement...utterly useless

I like well designed GT wings that help keep my car much more stable and then hold the back of my car down A LOT more than the standard thing when I go on the brakes at 150mph on the back straight of my local circuit before turning into a chicane...thanks

FDNewbie

iTrader: (10)

Dave, are you mad at me? lol

But you make good points. After reading the very LONG thread about spoilers a while back, and a recent one that (I think) Damian had started, I realized that my spoiler doesn't have the teardrop shape you speak of. I'm in the works of finding a better one.

Oh and engine mods are on the way. Patience man. My little incident forced the bodywork to come first, that's all. I thought it smarter to put all your resources into one project, finish it, then move to the next. So for me it was looks first, then go-fast parts later. Besides, c'mon, my engine bay is FAR from stock...I practically have all the bolt-ons...

FDNewbie

iTrader: (10)

Hey Dave

You know what...I've seen a couple of companies that have the exact same spoiler shape/design as mine, where the blades are actually concave, w/ the top side dipping in the middle, and the bottom rounded out. For example, take this FEED spoiler...

MakoDHardie

YESSSS!!!! Its about time you went looking for a new wing. I really was hoping you were gonna get Gargamel's C-West original piece.

I've got one of the imported GT wings that Chuck brings in from Japan. Its sitting in my storage unit with all my other body parts waiting for some snow to melt so we can get it out and around to some shops once my pallet gets here. If you're still doing body work, I'll sell you mine if you'll come pick it up because I don't think its gonna go on until later in the spring. Let me know.

-Dave

FDNewbie

iTrader: (10)

Dave,

I was just talking to Chuck about that wing like an hour ago. I think that wing is HUGE. It's more like a sail or somethin lol. I'm not sure it would flow too well w/ the car. I'm looking for function AND forum And I might still keep my spoiler...sorry lol. We'll see.

Did you see my last post about the FEED wing? It's the EXACT same blade design...

cabaynes

iTrader: (4)

Ramy (and others),

Not trying to gang up on you, but just wanted to pass on this info to help you understand a bit better.

The wing you have Ramy, much like the Feed wing in the picture betlow acts much like 2 spoilers stacked together. They use thin flat surfaces at an angle to act as a barrier to airflow which builds up a higher pressure in front of the spoiler. Think about the spoilers used on Nascar cars, only yours is raised up off the deck lid. The air that builds up in front of the spoiler pushes down on the spoiler, which pushes down on the car is is attatched to.



Take for example this drawing of a spoiler:



But in order to understand the idea of a wing, you must understand that there IS a difference between a spoiler and a wing. Like i said before, a spoiler is what you have, and what is usually found on the decklid or larger sedans and some (Nascar style) race cars.

However, the wings that are produced for GT cars much like the one below (from Rotary Extreme) act differently then spoilers. Wings perform very efficiently, generating lots of downforce for a lower penalty in drag. Spoilers are not as efficient, because they create more drag.

The wing works by differentiating pressure on the top and bottom surface of the wing. The higher the speed of a given volume of air, the lower the pressure of that air, and vice-versa. A wing makes the air passing under it travel a larger distance than the air passing over it. Because air molecules approaching the leading edge of the wing are forced to separate, some going over the top of the wing, and some going under the bottom, they are forced to travel differing distances in order to "Meet up" again at the trailing edge of the wing. This is part of Bernoulli's theory (like Dave stated earlier) The lower pressure area under the wing allows the higher pressure area above the wing to "push" down on the wing, and hence the car it's mounted to. See the diagram below:



And you can see the similarity in shape when you compare that drawing to the GT style wing here:



Also Ramy, you should note that the Feed wing you posted is the FEED GT-1
Check out the FEED GT-2 model here: http://www.pac-gate.co.jp/feed/fd3s/fd-gt2.jpg


-Charlie

FDNewbie

iTrader: (10)

Charlie,

All you guys rag on my car all the time, so I'm used to it lol But no, seriously, I actually take stuff like this to heart because I'm actually trying to learn here. I was aware that FEED changed their design in the GT2 wing. Is it just me, or was there a sudden breakthrough in wing design, and EVERYONE went from the GT1 design to the GT2 design? Cuz if memory serves me correctly, most of the GT1 cars were running the GT1 design or something very similar, be it a single or double decker. Now they're going w/ the tear-drop shape with that raised area in the middle 2/3s of the wing.

So Charlie, Dave, etc, thanks...I don't mind the constructive criticism at all. I was always quick to admit my spoiler causes a LOT of drag. What can I say...I bought it before I knew all this Guess it's gonna have to go...

Big Cat

If you REALLY want downforce for you car, lower it alot and get aluminum or carbon fibre plates on the bottom to smooth air flow. The smoother the surface the faster the airflow, the more downforce, the better handling. Get a diffuser as well. A diffuser is probably the most functional aero part you can buy for a passenger car especially a sporty one like an FD. All GT wings are a balance of form and function, drag force and drag, but my personal favorite in terms of the shape of the airfoil is the original C-West Carbon Fibre GT Wing. just my 2 cents.

Big Cat

i meant downforce and drag