E30 Aerodynamics

[squidmaster]

Are you disagreeing with me by partially agreeing with me and reiterating what I said? Could you maybe clear that up for me I guess I'm confused.

And what do you mean by "then be successfully directed to a proper rear wing to aid in downforce." Who's doing that? Where's that happened? How's that happening? With the airtabs? What are you basing that on? I'm sorry man but you've lost me on what exactly you're talking about. I'm talking about airtabs.

anyway I mocked them up and tossed them on my super basic e30 m3 model that I use for basic testing....... You can see the results for yourself here: http://sssquid.com/v2/airtabs/

I spent all day doing exactly this same thing so this is all I'm going to spend time on now. If someone wants to find out how their aero works, contact me.

[e30davie]

Check out this video the youtube video by channel "kyle drives" on vortex generators. Gives you an idea on how they work, and might aid in your decision.

If i remember correctly he talks about them on an evo, which is also an aerodynamic box, so perhaps quite simliar to an e30.

[2mAn]

Correct me if I'm wrong but I think the idea is that these pull the air off of the rear window, which can then be successfully directed to a proper rear wing to aid in downforce.

Without them, the air sort of slopes down the rear window and creates a low pressure zone as it circulates up and meets up with the air that's flowed over and under the car.

The sharp drop angle of the regular E30 rear glass ( and why the angle changed on the M3) isn't ideal. The air tabs are supposed to prevent that pressure zone. Combine this with a slippery belly and it should reduce the overall drag the car has

[squidmaster]

So, I understand the concept, however installing them on the roof would detract from the wing's operation.

a wing operates when it creates downforce, which it does by taking a perpendicular force and redirecting it.

Using those basically gives you a bubble butt to a teardrop taper-- and causes the air to condense back onto itself more efficiently (the "hyper fuel efficient" car design has a very long, fine taper at the end... usually).

These are moving the air AWAY from whatever's behind them. You'd probably have to extend your wing even higher to make proper use of it.

[e30_302]

http://www.airtab.com

[squidmaster]

But the manufacturer did? Do they have suggestions as to placement or anything? I've always been curious about those

[e30_302]

Nope, just seen the propaganda the manufacturer puts out.

[squidmaster]

Anyone actually tested those to find out where/why/if they work?

[e30_302]

For the airtabs: where it's flat and spaced the way they tell you to. Mine are laid out exactly as in your second picture, and on the rear quarter panel, and my wing end plates, and on the bottom of my splitter....I got a little carried away.

[squidmaster]

Eric, come by the shop when it opens in about a month and we can 3d scan your whole car to see how it can be improved.

Great photos. Did you make the aero yourself?

[2mAn]

So I bought some Vortex Generators made by airtabs. I'm not exactly sure how far back I should install them on the roof. I had planned to put them all the way back but the roof starts to slope down.

Anyone tried using VGs on the E30 roof?

edit: Heres some pics from earlier that I just placed on the roof

Not actually going to install these for a little while since a rear wing would be a good idea to add with it. I've got plans but for now I'm still learning the ideal location. I'm pretty sure I bought enough of these little guys but who knows.

I knew I wouldn't be able to go all the way to the rear window so I need to see if that's a problem, but I hope more reading will give me the answer.

For now, here's some pics since that's what we all want to see

At the edge...


Where it's flat:



Probably how they will get mounted, with a little more precise measurements:



Another option:


From the front


The second option leaves enough space between the outer ones that I can add more airtabs if I need it, but from an article I read, this many is about where any more and it doesnt really make a difference...

[Eric]

Anyone wanna put their aero where their mouth is?
https://www.instagram.com/p/BOSPw88AHbs/

Dude, we need to hang out!

I added a little bit of aero to the M3. I like the front splitter, but it needs to be stiffened and hung in a better method than it currently is. I'm currently pondering how to accomplish both.

M50_1020 by ericandshovin, on Flickr

L50_9072 by ericandshovin, on Flickr

C52_8459 by ericandshovin, on Flickr

C52_6260 by ericandshovin, on Flickr



M50_4351 by ericandshovin, on Flickr

M50_4580 by ericandshovin, on Flickr

[z28]

This thread keeps getting better and better, keep posting your setups guys.

[RoccoB517]

Anyone wanna put their aero where their mouth is?
https://www.instagram.com/p/BOSPw88AHbs/

Yes, I'd be curious to see what you guys think. I sent an email.

[Beej '86 325es]

E30 Aerodynamics

This thread got me interested in working on some under-car aero myself.

I decided that my BMP rear bumper area looks like a parachute underneath, so I've started focusing there. I found some 1/8" aluminum honeycomb at a good price, and it's the same stuff we use in aircraft. Here's what I've been working on the last couple of days: