vortex generators

[HyperTek]

lets talk about em.


anyone throw some on? just curious if there was any differences made. Dont give a fawk about how they look, this is all for aero tuning not puttin silly shit on ur car.
Seem to be a better benefit over roof spoilers with no background besides the typical "it looks tight"

Mitsubishi documentation on the effects
http://www.mitsubishi-motors.com/cor...004/16E_03.pdf

http://www.manufacturersdepot.com/SPD/vortekz-universal-vortex-generators-black-10-pack-vortekz-vortex-generators-are-universal-to-fit-virtually-all-cars--trucks--vans--suv's--rv's-etc-----800000A6-1180622063.jsp

[awesomenick]

I saw a tractor trailer with a ton of these airtab things on it the other day.

http://www.airtab.com/

They must do something cool if they spent the money to buy them. But I haven't personally tried it.

[BBSilvia]

haha i actually was thinking of putting it on my car...but decided not to, but my buddy put one on his subie looks nice but horrible fitment so dont buy knock off or super cheap!

[blownmotor]

They do work but it has to be placed at an optimal area with the correct size and design. And we need a wind tunnel to see where our seperation point is on all of our different model S platforms

[HyperTek]

http://pmsc.on.ca/bulletin/2005/JulAug%202005.pdf

they expect it must be improving the effectiveness of the rear spoiler

[ryguy]

I just helped my buddy put one on his Lancer. I didnt notice any difference, but who the hell knows, that Mitsubishi report was pretty scientifically conclusive. Plus, girls think random bits of plastic on your car are sexy.

[JRas]

Originally Posted by ryguy

I just helped my buddy put one on his Lancer. I didnt notice any difference, but who the hell knows, that Mitsubishi report was pretty scientifically conclusive. Plus, girls think random bits of plastic on your car are sexy.

because he wanted to look like an EVO

[Def]

Originally Posted by blownmotor

They do work but it has to be placed at an optimal area with the correct size and design. And we need a wind tunnel to see where our seperation point is on all of our different model S platforms

It's easy to tell where the separation point is on your car - just drive in misting rain and check where it stops streaming on the roof.


I rock some delta-shaped vortex generators like the Mitsubishi article investigated. If you actually read the research on VG's, you'll see they are pretty insensitive to placement as long as you're in the general ballpark. I get less dust on the hatch for sure, so they must be doing something.

[derek_s13]

dstar put these on his car. first 240 i've seen with em. matches the style he went for this time around i guess.

EDIT: yeah here:




get him in this thread, ask him and shit.

[initial_drifter]

http://zilvia.net/f/showthread.php?t=175795

it's about roof wings but it changes to VG's

good read

[S14SwimShark105]

roof wings don't do anything but mess up the airflow, it creates a suction action causing air to rush up the back window.

Don't know if this has been posted yet but everyone should read this, it's a really good review on the vortex generators. http://www.autospeed.com/A_3058/cms/article.html

[g6civcx]

Aero "tuning" is not about piecing together individual parts. Airflow interacts with the whole car so the car as a whole must be tested, ideally in a wind tunnel, to understand the full effect of a particular aero mod.

For example, learn from my teacher's mistake. He designed a very effective wing shape with full wind tunnel testing data. Then he installed it on the car and it didn't work so well. Downforce was nonexistent and drag went up significantly. His mistake was designing the wing without the car. The wing-to-body interaction is more important than the actual wing itself. What he found was that there was turbulence at the base of the wing, which stalled the air from ever making the wing effective.

Moral of the story: design all aero parts with the actual car to be applied on.

While the VG may be good for an Evo with a boxy frontal and side profile, S and Z cars, and especially fastbacks, have a more teardrop shape. It's not clear from Mitsu's white paper what the effect would be on our cars. Mitsu specifically limits their discussion to a sedan with a trunk. See at least page 11 column 1 paragraph 3, and throughout.

I say the best way to test the theory is to build a model and make your own wind tunnel with a big fan and a smoke machine Or if you're a computer genius you can run a simulation.

If you want your wing to truly be effective, the rear wing needs to be higher than the roofline! This is because airflow will not drop down at the rear windshield enough to make the wing work, regardless if you have VG or not. This is worsen as speed increases. To counter this, you need a large rear wing sticking up above the roofline to be in the line of airflow.

Otherwise I wouldn't waste money on aero stuff unless you really want the parts for asthetic value.

[HyperTek]

thats why we discussin it... theres side effects to everything.. I say could be looked at.

I threw a roof spoiler on my old S13... along with a kouki wing . pretty sure that made both the items useless lol

theres alot of stuff that would affect the overal aerodynamics, pop up headlights in up position, wheels sticking out, exhaust pipes sticking out over the rear bumper etc..

Im curious if there was any homework done in the design of vented fenders.

[suaknee]

I've always wondered about these too.

[GSXRJJordan]

^^^ Vented fenders, probably not. Besides, they're for engine/brake ventilation, not downforce (air rushing past the fenders pulls hot air from that area out).

What g6 said about the "car as a whole" is absolutely true though, you can't test individual parts effectively.

[sldbyuramg]

Originally Posted by JRas

because he wanted to look like an EVO

+1 lancers are gay as shit especially when people try to make them look like evos.

vortex generators are great if they are used in conjunction with the correct wing height for the targeted speed.

what im trying to say is that an evo mr vortex generators are optimal between "AROUND" 50mph to 80mph. between those speeds it supposedly adds 10 to 15 lbs more of downforce than without one. if you just buy one off EBAY for a 240sx it will help but it may only help at 100mph to 150mph... if you have no wing or if your wing is too high it may only work at very low speeds.
basically if you cant get your car into wind tunnel to find the optimal settings it may be for LOOKS only. and there may be a huge difference between hatch and coupe setups.

it will help with downforce, just at what speed may be a wild guess for our cars until someone does some real testing

[HyperTek]

high speed tunin nukka!
im still buildin my deck spoiler

[sldbyuramg]

im all about high speed tuning... i did a high speed trip from Alpine in san diego to Phoenix in 4 hrs well 4 hrs and 2 min. with a 10 min stop in yuma for gas. i was on my top speed limiter for 2 hours total and the longest run was 45 min consecutive. i had my Valentine 1 for safe travel... EVO8 with MBC set to 20lbs boost K&N drop in filter, turbo back exhaust, and tanabe lowering springs

[S13_marine]

If you have no wing, VG's aren't going to do anything. The purpose of a vortex generator is to disrupt airflow, or create turbulance, but in a specific air stream in order to use that air to create a desired effect on another surface. Aircraft use them mainly to disrupt air movment over the wings, creating more air surface to hit the ailerons etc... So, in short, unless you have a rear spoiler or wing, it not gonna do anything but look EVO-ish. But with the right sized vortex generators and an ajustable wing, you'd have a pretty effective way to create more downforce in the rear.

[Def]

Originally Posted by S13_marine

If you have no wing, VG's aren't going to do anything. The purpose of a vortex generator is to disrupt airflow, or create turbulance, but in a specific air stream in order to use that air to create a desired effect on another surface. Aircraft use them mainly to disrupt air movment over the wings, creating more air surface to hit the ailerons etc... So, in short, unless you have a rear spoiler or wing, it not gonna do anything but look EVO-ish. But with the right sized vortex generators and an ajustable wing, you'd have a pretty effective way to create more downforce in the rear.

Vortex generators create a streamwise vortex that energizes the flow to reattach it to a surface. In the case of an aircraft, it's trying to get the flow reattached on the wing at higher angles of attack such that the control surfaces are actually acting in airflow. They typically use dual delta wing shapes with a set ~15 deg angle of attack to the incoming streamline.


As far as your wing needing to be above the roofline - totally false. The flow is not separated from the roofline back when looking at a velocity plot. Yes, a wing 2" off the decklid will not work well, that's common sense and a simple tuft test could tell you that. Once you get about 12" off the deck you're probably going to be in "mostly" clean flow, and above 14" on our cars it's probably going to be almost completely linear and horizontal flow.


You do not need a wind tunnel to do aero work. In fact, some simple tools like a manometer/inches of water pressure gauge, some wool tufts plus tape and a little knowledge will go a LONG way towards helping out aero on your car. I'm betting most people who say you absolutely must have a wind tunnel to do any aero work on a car have never even stepped foot inside a wind tunnel, or have an idea of what really goes on inside one. I use 'em all the time, and I'm saying large general changes are easy to make without analyzing things within a gnat's ass. It's called back of the envelope engineering, and it's more common than you think, and the GOOD engineers can make absolutely amazing observations with some observations and a few simple calculations about what needs to happen(in some cases).

[CKAMC]

I myself am looking into getting a set of sards vg's for my s14.. much more functional than a roof spoiler. Might get a APR spoiler later on to help with its function

I am still trying to find out how to best place these without having to rent out a wind tunnel.

here is quite a few placed on a RD.... rather extreme FD


but buy the looks of the wing height in the sards image... doesn't look like it needs to sit up there that high *the actual wing*



sards are a bit bigger than the oem evo or the chargespeed one's being sold right now.

[HyperTek]

im curious if the japanese companies do actual wind tunnel testing? i recall back when sleepy eye controllers where designed to be air ducts lol

[Kougeki]

Unless you're actually going like 70+ MPH, i don't think these make a difference, the Chrysler Crossfire's wing goes up once it hits 60 MPH.
If you're on the freeway constantly, it probably can't hurt.
If you're sliding... why put one on? ?

[Def]

Those SARD VGs aren't going to make much of a vortex being almost parallel with the flow for most of the middle of the roof. They need to have some angle of attack to the incoming air to make a good vortex. That said, those things are ginormous to the point of HURTING things more than helping. You're going to add way more drag with something sticking up 4-6x the boundary layer thickness than a proper VG that's about 1.5-2x the BL thickness. So you might reattach flow on the rear window well, but sticking that much crap out into the flow doesn't come without penalties(drag). Plus there is a clear point of diminishing returns once you get about 2x the BL thickness as far as generating a more "useful" vortex.

[HyperTek]

might be good for.. well.. incase you stall in mid air... i kid i kid

[CKAMC]

Originally Posted by Kougeki

Unless you're actually going like 70+ MPH, i don't think these make a difference, the Chrysler Crossfire's wing goes up once it hits 60 MPH.
If you're on the freeway constantly, it probably can't hurt.
If you're sliding... why put one on? ?

not everyone here is into drifting.....

yeah I know there are a few of us... try and keep us in mind

[NI_YON_Zenki]

Nice Rhyme Tek.


OOH, 757 Baby! Jumbo Flow. High Up in the sky Crushin' folks Belly Below!

lol. but, yeah, Nice rhyme Tek.

[racepar1]

Yes they work, yes they have been tested MANY times.

[HyperTek]

looking at the Sard units however, due to their size, maybe they are more like fins instead of vgs?

[blownoffvalve]

that's a lot of science.... but it's for going fast