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Vortex generators?

7K views 29 replies 14 participants last post by  SterlingSaab 
#1 ·
Browsing around, I found THIS (pdf) on Mitsubishi's site - it's basically an in depth analysis into these 'Vortex Generators' that supposedly break up the airflow at the back of the car.

Now, I'm a natural born cynic, but the theory seems sound, so much so that the Lancer and now the Scooby STI are both fitted with these from the factory.

To that end - a quick search on Ebay and I've ordered some. For the princely price of £14 including postage, they will soon be winging (if you'll forgive the pun!) their way to me.

Before everyone starts screaming 'SNAKE OIL!!!' - here's my reasoning:
  • They are self adhesive - therefore easily removed.
  • They might actually look ok, in black, on a black car (which mine is!)
  • They might... only might... actually work!
So... I will post up results of my 'tests' when they arrive and have been fitted - should nicely coencide with the arrival of my new downpipe from the States! :cheesy:

Ladies and gentlemen - discuss! ;)
 
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#3 ·
Er - sort of.. they are fitted to the boot (or trunk for you guys), or rather on the roof just before the boot/trunk and yeah, they are supposed to reduce drag and increase downforce - at least it's not a resistor in a fancy box :lol:
 
#6 ·
Ah well, I'm not going to fit a shopping trolley spoiler on the back! I will see how they go - will let you guys know.
 
#9 ·
Well it's too late now!! Anyway, I think they might well look quite pleasantly aggressive on the back of the car :lol:
 
#10 ·
StormCrow said:
Er - sort of.. they are fitted to the boot (or trunk for you guys), or rather on the roof just before the boot/trunk and yeah, they are supposed to reduce drag and increase downforce - at least it's not a resistor in a fancy box :lol:
I'm not sure how they would reduce drag, you are only adding more area that the air has to go around, thus creating more drag.... Also you don't want downforce, at least not on the rear. We have front wheel drive cars....

That being said, will you ever achieve a speed that the aerodynamics of these vortex generators will need to generate downforce? Probably not. I personally think they might look pretty cool. I'll be looking forward to seeing some pictures installed. Are you going to install them on the little lip spoiler thing on the boot/trunk? I think they would look best on the top of the hatch.
 
#11 ·
I'm thinking that they are going to be installed on the top of the roof - around my Viggen antenna (along the back of the roof) just before the split for the boot...
 
#13 ·
makes a difference on a viggen

StormCrow said:
I'm thinking that they are going to be installed on the top of the roof - around my Viggen antenna (along the back of the roof) just before the split for the boot...
when you say around the antenna on your Viggen ..... you mean the car right ?
not the plane ? :eek:
J/K , fit em first find out later they look smart .
 
#15 ·
Vortex generators on airplanes are strategically placed at key points along the wing and other aerodynamic surfaces. You can't just go placing them anywhere and expect them to do anything at all. As far as using them on cars in the first place? Race cars, maybe. Street cars? Street 'race' cars? Ricers? Hell no.

Vortex generators work by keeping the airflow flowing along the surface in the boundary layer. The VGs impart a vortex of air that prevents the air from "detaching" from the boundary layer and become turbulent. This is critical in airplanes in certain areas and at very specific and critcal conditions. During regular cruise flight they have little to no affect. Even with the advances in aerodynamics and styling, a road vehicle has the aerodynamic efficiency of a thrown stone. Maybe a Mclaren F1 or an Indy car, but not a Mitsubishi Lancer or Honda Civic.

http://www.microaero.com/pages/v_howvgswrk.html

http://www.aerospaceweb.org/question/aerodynamics/q0009.shtml
 
#16 · (Edited)
Also, THIS is the correct link to the above article.


Application of the VGs of the optimum shape determined​

through the abovementioned analyses to the​

Mitsubishi LANCER EVOLUTION showed a 0.006

reduction in both the drag coefficient and lift coefficient.​

...and that is under sterile, lab conditions. That's the equivilent of a leaf stuck in your windshield wiper, or antenna up versus antenna down.​
Spend more time worrying about your tire pressure and how you drive. Don't stick VGs on your car.​
 
#17 ·
Yeah that sort of confirms what I've been thinking, but never mind, they are on their way now!

And it says that it will stop me stalling (reading the link you gave me) so it can't be bad right? :lol:
 
#18 ·
i actually have these on the rear end of my roof on my 900...granted i dont know if they work or not, but they do add some style to the look of my car...they are stick on with 3M tape on the underside....ill take a pic and post them 2night...i actually got them them autozone
 
#25 ·
I think the look is good... just subtle enough.

A clarification is in order, however. Vortex generators are meant to break up the laminar flow of air over a surface.

Here's the Cliffs Notes version: Smooth, laminar air = low pressure. Turbulent, swirling air = high pressure. Vortex generators are designed to relieve low pressure areas across a surface. In the case of a ground vehicle their function is to reduce lift.

Rally cars (Evo, STi) use the turbulent air coming off the vortex generators mounted on the roof of the car to generate downforce across the wing on the decklid.

-Tom

edit: Wow, that was some first post! Glad to be here, guys and gals. -T
 
#26 ·
IL8APEX said:
I think the look is good... just subtle enough.

A clarification is in order, however. Vortex generators are meant to break up the laminar flow of air over a surface.

Here's the Cliffs Notes version: Smooth, laminar air = low pressure. Turbulent, swirling air = high pressure. Vortex generators are designed to relieve low pressure areas across a surface. In the case of a ground vehicle their function is to reduce lift.

Rally cars (Evo, STi) use the turbulent air coming off the vortex generators mounted on the roof of the car to generate downforce across the wing on the decklid.

-Tom



edit: Wow, that was some first post! Glad to be here, guys and gals. -T
Here is my point, the low pressure that they reduce is the area immediatly after roof around the back glass area. With a hatch, the low pressure is situated much farther back and lower, basically behind the rear bumper.

I don't think they look too bad though

Welcome IL8APEX!
 
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