Functional rear spoilers?

[Sykohtic]

yeah I agree with you. I think you posted yours while I was still typing mine.

still, I think the distinction is important. shopping cart wings from the F&F days are definitely not for the same purpose as an is trunk spoiler. :p

Yeah, definitely not for the same purpose. Those were the days when the more wingy and edgy bits you could bolt on were as good as a turbo... All the wings for all the things. That dowforce though....

[2mAn]

Cool, you guys know more about aero than I do... :up:

so, whats a good option out there thats a good balance?

[nando]

most of the good parts are going to be hard to find/expensive, unless you don't mind something that doesn't really fit right.

there's a Zender wing that's basically the same as the E30 M3s, you can get the DTM flap for it too. or Mtech 1 which is a bit bigger than the standard is lip. Don't know how well the Mtech 2 works. there's lots of other E30 specific spoilers too.

[Liquidity]

a spoiler disrupts the turbulent air at the rear of the car, making it more aerodynamic by reducing drag.

a wing provides downforce. it increases drag.

I have to question where you got this information from. A spoiler on a NASCAR is most certainly NOT there for aerodynamics and also does NOT reduce drag. It is there for one purpose and one purpose only - rear downforce - and the taller they are, the more they slow down the car which is why NASCAR increased its height in yet another attempt to slow down the ever increasing speeds of the cars.

Ever heard the saying *a square is a rectangle but a rectangle is not a square?* Same thing applies here. A wing is a spoiler but a spoiler is not a wing.

[Bimmer_man]

Liquidity where did you get that info? I was told that the spoiler is to reduce turbulence. If you ride in a nascar and are surrounded by other cars going close to 200mph its similar to a semi speeding past you when you are sitting still there is a lot of wind thats built up from all the cars around you. So it makes perfect sense for the spoilers to be exactly that a spoiler.

[nando]

I got my information from the definition of the words, lol.

a wing provides uplift or downforce, it's got a pretty specific shape. You know, airplanes and stuff.

a spoiler "spoils" the airflow. it can also provide a bit of downforce but a wing is a more effective shape. even if a spoiler can create some downforce, it's still not a wing. unless you've seen some pretty crazy airplanes I've never heard of..

[Liquidity]

Spoilers have nothing to do with turbulent air. They create turbulent air. They were invented for aircraft to decrease total lift by inducing downforce.

http://books.google.com/books?id=QCgDAAAAMBAJ&pg=PA91&dq=popular+science+1930&hl=en&ei=AnvcTt6DBMePgwfR96XpDA&sa=X&oi=book_result&ct=result&resnum=10&ved=0CFYQ6AEwCThu#v=onepage&q&f=true

[ak-]

most of the good parts are going to be hard to find/expensive, unless you don't mind something that doesn't really fit right.

there's a Zender wing that's basically the same as the E30 M3s, you can get the DTM flap for it too. or Mtech 1 which is a bit bigger than the standard is lip. Don't know how well the Mtech 2 works. there's lots of other E30 specific spoilers too.

Considering this, what's your opinion on the larger E28 MT1 spoilers many of us bolt on and Fiberwerk's DTM Wing for non-M's he sells?
It's been collecting dust in my shopping cart on his site for quite some time..

[Liquidity]

The reality is when you say "spoiler" you should be referring to one of these,











And when you say "wing" you should be referring to one of these.

[ak-]

Let's all beat up nando

[pantelones]

I've always understood that downforce is negligible at speeds under 100 mph with just about any wing on any car.

Formula one cars (used to...) have enough theoretical down force to drive upside down at 80mph.

Let's all beat up nando

Indeed, he speaks of things I can not fathom...

[15Michaeljoseph]

ahhh the high society. who needs school when you have r3v


--Mike

[Jand3rson]

Formula one cars (used to...) have enough theoretical down force to drive upside down at 80mph.

Ridiculous comparison.

Formula 1 cars aren't street cars. They're basically an airplane on wheels, only built to operate in the exact opposite manner (downforce rather than lift).

[Sykohtic]

I think everyone here is taking the black and white definition of wing vs spoiler way too close-mindedly. As I mentioned in my earlier posts, while there ARE white and black designations about wings and spoilers, the two CAN cross in purpose. I promise you, not all the bits you put on the back of your car = downforce or drag. Airflow itself is just as important to speed and handling as downforce and drag are.

I actually mentioned the NASCAR rear spoiler in my earlier posts. Yes it is a spoiler. Yes it also produces a lot of downforce. That doesn't mean it isn't also there to work with the airflow. In fact, if you look at the NASCAR spoiler setup, you'll realize there's a lot more to it than slapping an 1/8 inch aluminum plate back there and adjusting angle for downforce. There's also a roof splitter that runs vertically down the passenger side rear glass back to the rear spoiler, as well as a dip cut into the rear spoiler for an air channel off the roofline and rear deck to relieve low pressure zones and optimize airflow. The idea of the combination is to make the air flow properly to optimize downforce and keep the flowing air pressure up on the rear of the car and increase left hand turning capabilities by channeling other air flow off the left rear corner of the car (which pushes the rear end more right, making aerodynamic oversteer). You'll occasionally see a car spin for no good reason to do with physical contact, and this is actually because another car gets at just the right angle to alter that airflow off of the first car and because of the disrupted airflow, the heavy air pressure on the rear of the car is reduced, and low pressure zones generate and the rear end lifts and spins out to the right. Long story made short, a NASCAR spoiler does function heavily to create masses of downforce, but it also has a great deal to do with air flow and rear turbulence.

As I said, not all the bits for the back of your car make downforce, or at least not as a primary effect/not as an effect that is more than marginal. Many of the spoilers are meant to optimize airflow in such a way that smooths it out off the back of the car and reduces lift without creating masses of drag. This can often actually slightly increase top speed and have a real effect on stability at high speeds.

Downforce and lift reduction are the same but different. They are technically considered the same thing for most practical purposes. However, you dont necessarily have to increase downforce to reduce lift. The "IS" airdam, for example, is meant to optimize airflow around the front of the car and under the car. It produces some drag and downforce as by products, but its essentially there to push the air around the sides of the car and make a more straight flow under the car so that the airflow generates less lift. It isn't a direct stab for dowforce, though you can add splitters on the bottom of it to increase the amount of byproduct downforce it creates.

This isn't to say there isn't such a thing as a downforce aimed wing for the E30. The M3 wing is indeed a wing that seems based mainly on downforce. It is raised up by the rear sail and expanded deck lid to make it more effective by increasing airflow to it and henceforth increasing the amount of potential downforce it creates. That being said, the look-a-like wings like the Fiberwerks wing for NON M3 cars is less effective and while it is still very downforce focused, it probably functions more to improve airflow than it does to produce downforce because of where its located and the angle by which the air hits it. If youre gonna go that route, get the DTM flap for it. That WILL make dowforce, and will make a lot (as well as a lot of drag), and it will also shave a MPH or two off your top speed (most likely). There are also examples of spoiler-wing combos like off the Ford Merkur XR4ti and Sierra Cosworth stuff.

Spoiler versus wing for me is more about the form which the item takes in my opinion as opposed to the actual function. Functions can be shared between the two different types. For me, a spoiler is an item that functions as more of an extension of the car's body, mostly in a lengthwise perspective, that has to do with airflow over and off the body. A wing is a sort of platform added to the car to extend the surface of the car in usually an upward fashion, and is meant to slot into a zone of the airflow off the car's body that is otherwise unchecked aerodynamically by the shape of the car. In easy terms, you have a flat piece of 1/4 inch steel in a wind tunnel. You flow air over this piece. You add a spoiler because you want to work with the air that's actually flowing along the metal. You add a wing because you want to work more with the air that's flowing in the zone above the metal. That's somewhat accurate at least, but again, this isn't a subject of absolutes.

[Sykohtic]

Cool, you guys know more about aero than I do... :up:

so, whats a good option out there thats a good balance?

Thats honestly a really hard question. Testing them is the only way to know and there isn't much aerodynamic data to go off of. The best thing that could happen is if someone had a test car and we brought several different wings/spoilers to test on that one test car.

The M3 look-a-like wing with the flap probably does pretty well, and you could in theory custom make a flap for the rear that wasnt as dead curve up so that it wasn't such a drag generator, but without testing, impossible to know. The Pfeba Heckspoiler, Hartage spoiler, and E28 MT1 spoiler could probably make a little extra downforce over the IS spoiler, though they should also work as a larger extension surface to possibly shave just that much more lift out of the rear of the car (not to say the IS spoiler is at all ineffective though). Not sure about MT2 spoiler, but the sideskirts most likely help your airflow down the side and under the car. All of that is just theory though...