Excellent technical paper. I found the similarities between aircraft wing VG design and the Evo's (delta shape) very interesting. Neat stuff and thanks.

Speedlimit....

 

[QUOTE=x838nwy]Ahh.... so that's how it works. So the standard wing setup (w/o the vg) is pretty much too low and the separation (w/o the vg) mucks up the flow. If it presents the wing with a nicer flow, then the wing will work better and looks like they've managed to reduce the drag too.
good.

no free rides, the vg s create drag too, have to in order to work. granted not much. but yes the wing is to low, the vg s help in that regard because they tend to make the air follow the curve of the rear a LITTLE better.

as the air breaks loose at the sharp bend at rear of top it swirls trying to fill the low pressure.
it is not the same but think of holding a flag in a howling wind. vrs holding a piece of sheet metal in the same direction.

 

[QUOTE=nothere]
Mate, in the paper by mistuishi, drag is reduced...

 

I was not clear, they have to create drag to work, they are in effect making a turbulent boundary layer. Pound for pound they are an improvement
The net effect is good, you sure wouldn't see them on aircraft wings if they weren't.

regarding the mitsu paper
I think you will find the pictures describing the high pressure / low pressure areas to be very speed specific. That the pressure areas will vary widely with speed.

Again I am not arguing their usefulness. Any effort in making the rear window area less turbulent is good.

 

True, true. i wonder how speed sensitive it is.... the 06 STI also has a very slim spoiler roughly in this position. Wonder whether they are trying to do the same thing...

 

I guess it all comes down to how fast are you at the end of the 1/4 mile. Do you think you will benefit from a wing to press down on the tires for traction to help going faster and not 'take off' like the top fuel funny cars? (They are running more significant HP as well)
Or Evos are fast, but not fast enough for the wing to do much of a difference?

 

the vg would help a tiny bit, the wing would not. since nothing the wing does is helpful in a drag race.

 

ok.. well I suppose i will just try the good ol method of with and without next time I get out. At 130mph traction isnt the problem... wind resistance is. At the same time aerodnamics is as well. If you can gain 1-3 mph at the speeds of 130 it is a pretty big deal to me. Roughly the same as increasing the power 10-30hp. Not bad for just removing a part temporarily.

 

Great post, I think next spring when the weather clears a wing on test and wing off test is needed. I think the wing hurts mph in the quarter and the faster one goes the worse it is.

 

Maybe I will get bored and take a drive to test it out.... Otherwise I can take a 'test' run on a 'track' and simply measure the 60-120 mph in 4th or something like that. Otherwise it will just have to wait until the normal tracks open up around here.

 

I don't think the wing will effect mph in the 1/4 much if anything. I think the loss of wieght will play more of a roll.

 

Someone needs to test this, I'm sure there would be a lot of people interested in the result of a with and without wing test.

 

At the speed you're going through in the 1/4, the wing isn't doing you any good. It might be hurting a little.. The wing's good in high-speed sweepers where it'll put weight on the tires for added traction. It'll hurt on the straights, but the trade-off is worth it. You'll see top fuel dragsters with big wings, but they're going 300 miles per hour, and need all the downforce they can get to keep the 5000hp motor from spinning up the rear. I think your situation requires as slippery of a car as you can make.

 

You guys are over complicating things. Look to the pros and their 8 second Evos. AMS and Buschur. No need to reinvent the wheel.

 

Guys, keep in mind that TrinaBabe is talking about drag strip trap speeds that are probably higher than most people's sustained road course track speeds. Granted he is accelerating from 0 mph all the way through the run, and not maintaining a set speed anywhere. So I think one would need a graph of mph to feet traveled to even start to tackle this computation. However, I'm a mathematical retard, so take that with a grain of salt. Some Engineer needs to take the truth of that concept further...

BTW... this is a great topic. After a little more exposure, I say it needs to go in the Advanced section.