Can rear wing/spoilers improve fuel economy

[OTEP]

Yung isang neighbor namin dito nagbebenta ng 'GAS SAVING TURBULENCE SPOILER'. hahaha. Parang yung mga nasa bubong ng Lancer EVO.

Nakita ko nakalagay sa Pajero at sa Cefiro. Sino ba namang tuod ang bibili nun?

[redorange]

Spoilers afaik e para itulak ung rear ng kotse on the road and also causes drag. Alam ko din epektib ito sa mga rear wheel drive cars to increase speed only. dahil mas makapit ung gulong sa kalsada pero hindi sa mga front wheel drive cars. u need front wings for front wheel drive cars.

It does not make better fuel mileage because it causes drag. adds weight as you increase speed.

The spoiler actually doesn't increase speed in rwd cars it creates drag. What it does do is create better traction and stability at high speed. An example of this are the cars used at the Bonneville Salt Flats during speed week for world record top speed runs, granted they are jet powered but if you notice there are no wings to create more drag.
http://en.wikipedia.org/wiki/Blue_Flame

Heres another site that explains everything much better.
http://www.autozine.org/technical_sc..._aero.htm#Drag

[yebo]

spoilers? additional drag lang yan. the only spoiler i will recommend are the OEM spoiler that they supply at car dealers. that is wind tunnel tested. pag bili mo ng brand new car palagyan mo na sa dealer. but for aftermarket spoilers, NO.

wings? sa sanitary napkin lang yun!

since sabi mo mahangin sa star tollway, bili ka na lang ng sail na para sa windsurfing. pag dating mo sa star tollway, turn off engine, put to neutral and set the sail. dun ka sa roof ng car hehehehe!

[baiskee]

nakow...in a particular speed, but for city driving...WALA. kahit na siguro 100-120kmh di pa ramdam eh.

[wewoy_romero]

common sense tells me: NOPE. they add "useless" weight. more weight, higher fuel consumption

[niky]

http://www.airtab.com/



Try these. They actually work, but mostly for big trucks and trailers, where drag from the trailing edge causes a huge loss of efficiency. They work by creating vortices similar to those created by Mitsubishi's "shark teeth", but instead of using it to force air to flow down to the rear spoiler for maximum downforce, they cause the turbulent air at the back of the vehicle to lift away from the body.



One way to demonstrate this is to affix devices like this (they're not hard to make... maybe our resident mad-scientist, ghosthunter, would like to try it) on the roof and tape streamers to the rear windshield. Without the devices, turbulent air flows down across the windshield... with them, the streamers should remain calm at speeds above 60 km/h.

From word on the internet, though, the fuel savings possible are very small for cars... about 0.5 - 1 km/l for small cars at highway speeds. The big savings are for trucks, but there are new techniques that might make this obsolete... a fairing for truck rear ends that does the same thing.

[mbeige]

That's why they're spoilers, they spoil the drag coefficient for sports cars and allow more downforce on the rear (preventing it from flying off, technically). This will definitely increase fuel consumption due to the added downforce (if it functions like a true spoiler).

No, they don't improve fuel economy. What improves fuel economy is a car that slips through the air easily than one that increases the downforce (thereby having more weight to push forward--requiring more fuel).

The weight issue is negligible since it's not that heavy.

[Dr.Kamiya]

If the car is specifically designed for it, yes.

The Lancer Evolution VIII and IX both have better drag coefficients with the wing, compared to without. This is partially because of the vortex generators on top of the car. The vortex generators funnel the air down, and the rear wing further compresses this air, making it flow at high speed. In essence, the rear downforce is generated through a pressure difference between the underside and the upper side of the whole car, not just the upper and lower side of the rear wing. Thanks to the combination of the vortex generators, the car generates good downforce without needed a high angle of attack on the wing.

Here's a link to the paper on the study conducted for the Evo's vortex generators:
http://www.mitsubishi-motors.com/cor...004/16E_03.pdf

[Dr.Kamiya]

To add to my post above:

We generally get drag when the air separates from the car's bodywork, like so:



The vortex generators can make it so the airflow is flush with the rear windscreen, and then the rear wing makes it so the airflow is flush with the trunk. The combination of vortex generator + rear wing allows the air to flow very quickly, and detach smoothly off of the back of the Lancer Evo VIII and IX. Without the vortex generators, it's just another car with a wing. Without the wing, we would still have the air detach from the car at the trunk.

Here is how the rear spoiler works to keep the airflow close to the body. You'll see it's not just "creating drag":


And the pressure difference between this fast air, and the air that flowed straight through the bottom of the car is what gives the car downforce. Not just the force on top of the wing.

The car manages to have both downforce and low drag through a good combination of technologies.

[OTEP]

However, to get any benefit from a vortex generator. You must run the vehicle at constant speed and with sufficient airflow over the generators.

Pretty much useless in local metro traffic conditions wherein cars rarely reach cruising speed. More like crawling speed. :lol: