aero tech- wings, lips, diffusers, canards, etc.

[roastbeef]

they are justified by the many people who use them at the track and are faster with them.

understeer is fairly easy to dial out of these cars with just a few mods.

[redpriest]

Originally Posted by roastbeef

they are justified by the many people who use them at the track and are faster with them.

understeer is fairly easy to dial out of these cars with just a few mods.

Or just press your foot down with DSC off, I find that helps rotate the car as well.

[leo95se]

Originally Posted by roastbeef

they are justified by the many people who use them at the track and are faster with them.

understeer is fairly easy to dial out of these cars with just a few mods.

Can you explain how, or what mods?

you started this thread, correct? Why did you ask if you already knew?

I believe wings add value, but they need to be balanced with appropriate frontal downforce. my guess is that there is more benefit from canards to do this, as they are directing airflow along the shape of the car, where a lip needs to be very low in order to create a negative pressure area, vs just splitting airflow (our cars sit too high). i have a lip too, but cant say i noticed any big difference.

[roastbeef]

Originally Posted by leo95se

Can you explain how, or what mods?

you started this thread, correct? Why did you ask if you already knew?

I believe wings add value, but they need to be balanced with appropriate frontal downforce. my guess is that there is more benefit from canards to do this, as they are directing airflow along the shape of the car, where a lip needs to be very low in order to create a negative pressure area, vs just splitting airflow (our cars sit too high). i have a lip too, but cant say i noticed any big difference.

i have ground control camber plates set at -3. i'm also running 273/35/18 tires all the way around. square setups help in keeping the car rotate-able. this setup combined gives a ton more turn-in and reduces understeer greatly. i still get understeer if i'm getting into the gas too soon or if i get into a sweeper a little too fast. it is easily dialed back with easing off the throttle. if i really screw up and have an "oh shit!" moment, i can lift off the throttle more abruptly and really get the front to grip. granted, MDM keeps the rear from sliding out, but i do get a lot more turn-in and the corner is botched- but i don't go off track (mission accomplished).

i started this thread to talk about aero. lots of people on here are running many combinations of different aero parts and i want to get feedback as i begin the trial and error of trying to add balanced aero to my car.
some people might advise against certain components, and some will recommend other components i haven't thought of or considered. i'm here to learn.

i already learned that a rear diffuser can help with rear downforce. i had previously thought it would reduce drag. maybe it still does, but also increases downforce... i don't know. if i feel like i need more rear downforce after some experimenting, i'll consider a rear diffuser.

i'm also curious if reducing weight in the rear can be compensated for with downforce. i can get rid of almost 100lbs in the rear of the car pretty easily by going with a lightweight battery, trunk, and removing the rear seats. is the answer to keeping a balanced car more rear downforce? switching to a staggered track setup? i don't know. i'm hoping to learn that as well.

[leo95se]

agreed on tires, and that is with a stock (non-aero) setup. id love to hear more about the combinations people run and see whats working. many seem to be leaning toward a simple small spoiler vs a wing, as mentioned above. this probably creates less of a top end sacrifice.

my worry is that this heavy beast of a car is easy to get to understeer as it is (slow-ish in, fast out) and adding rear downforce will accentuate it.

my hope is with the right shape and height, it will create grip, allow slip, and not understeer.

[roastbeef]

sounds like we're in the same boat. i already have the oem performance carbon decklid spoiler. i swear it makes a difference. might me slight, but it does. i had taken it off in the past and it was taking me longer than expected to get all the adhesive off. anyways, i went to a track day with a naked trunk and i swear the car was a bit more loose, but not in a good way.
it was also pretty hot that day and i'm relatively new to tracking and not as consistent as i would need to be to really make a solid conclusion- but i believe it makes a difference.

i thought about it like this- my hand is about as tall as the rear decklid spoiler. sticking my hand out of the window at about the angle of the rear decklid spoiler at 80 mph- its significant force. not scientific- i know. but that combined with my naked trunk track day experience has led me to believe that it is more than just a pretty piece of carbon that sits on the trunk.

there are a few of us (me, elim11, m3number86) that just got aero, so i'm sure this thread will take off with more discussion. i'm sure redpriest is going to jump on board soon as well.

i want to be as fast as the coilover guys with my oem suspension. then when i get coils it will be that much schweeter....

[M3 Number 86]

Originally Posted by leo95se

agreed on tires, and that is with a stock (non-aero) setup. id love to hear more about the combinations people run and see whats working. many seem to be leaning toward a simple small spoiler vs a wing, as mentioned above. this probably creates less of a top end sacrifice.

my worry is that this heavy beast of a car is easy to get to understeer as it is (slow-ish in, fast out) and adding rear downforce will accentuate it.

my hope is with the right shape and height, it will create grip, allow slip, and not understeer.

don't know what your setup is but mine tends to over steer. nothing crazy though.

[MasterP]

Aero is the final frontier. It's what you go to when you can't add more power, more tire, more suspension or less weight.

I'm running the APR GT250 71", GT4 Splitter with front Undertray/splitter, Double GT4 Canards, Varis rear diffuser and under tray. I too would like vented/louvered fenders and seal up the bottom of the car some more. My car is very balanced on 305's squared. It did get draggy though but it's worth the trade off. At COTA I've lost about 5 MPH on the long back straight but it's worth what I gained in T2, the esses, and it's huge in the T16-18 carousel.

There's a local that runs two giant wings on both ends of his E92 that's cleaning up in TT3.

[roastbeef]

i really like what Sebringjetta did with his vented rear bumper. i'd be curious if this helped with drag.
http://www.m3post.com/forums/showthread.php?t=1099451

[Richbot]

I would love to see some real data on those rear full-width up to the diff diffuser setups. That seems like a no-downsides way to add some speed to this car, if they work

[roastbeef]

its hard to say... i'd like to see someone like randy pobst drive my car, install a true rear diffuser and see what he says after a few more laps.
because the reality is, i'm nowhere near being able to be consistent enough (especially at a weekend track event) to say for sure if something like a diffuser is making a difference or not.

[roastbeef]

anyone have a leftover template for mounting a gts style wing?

[GabeS]

[jakob66]

Hey guys
Just want to give you a heads up on my diffuser system that I developed and built in the last couple of months. It goes all the way to the front axle. I installed rear travel transducer with display in dash so I can see what happens in the rear. I tested on public roads and it does generate downforce. I will report back after race this weekend.
I received plenty requests to make a built thread of my car but I have to apologize I just had no time. Maybe later in the year.
Cheers

[roastbeef]

Originally Posted by jakob66

Hey guys
Just want to give you a heads up on my diffuser system that I developed and built in the last couple of months. It goes all the way to the front axle. I installed rear travel transducer with display in dash so I can see what happens in the rear. I tested on public roads and it does generate downforce. I will report back after race this weekend.
I received plenty requests to make a built thread of my car but I have to apologize I just had no time. Maybe later in the year.
Cheers
Attachment 1478110
Attachment 1478111

Wow thanks for posting. Do you have any underbody pics by chance?

[jakob66]

Originally Posted by roastbeef

Wow thanks for posting. Do you have any underbody pics by chance?

Just a teaser for now
.

[Greg S]

Nice work on the diffuser, what material did you use?

[roastbeef]

Originally Posted by jakob66

Just a teaser for now
.

Attachment 1478139

I'll be watching for that build thread!

[jakob66]

Originally Posted by Greg S

Nice work on the diffuser, what material did you use?

Hey Greg!
Aluminum.
Are you racing TT3 at Watkins Glen?
Any updates from your racer?

[okusa]

Originally Posted by jakob66

Just a teaser for now
.

Attachment 1478139

Wondering if the pipes way up there will melt the rear bumper.

[jakob66]

Originally Posted by okusa

Wondering if the pipes way up there will melt the rear bumper.

no, they are wrapped.

[Richbot]

The poor corner worker who has to grab that tow hook better have welding gloves on

That's awesome