mercedes inspired dams

[lunarhighway]

i found this picture to be quite inspirational.


not only is this one of the best oem undertrays on a production car i've seen, but also it's got a number of interesing features.



the riblets on the undertray seem intentional and likely are for aero rather than structural, as they're not used anywhere else.

but also the angled wheeldams behind the bumper is quite interesing.

because i love the concept of dams but never seem to get them right i thought i'd give this configuration a try

i'd previously enlarged the side dams on my car but this didn't produce the desired effect, so i radically trimmed them down... and added mercedes inspired angled dams

on my first testdrive i didn't get the feeling they added drag so that's a good thing, but cornering definately felt different... i'f i'm honest i'd say the car seemed to have a bit more body roll, but i'm still evaluating so we'll see

here's some pics

[basjoos]

Although its a little more difficult to mount on the car's frame, it would help if the side dams were located more directly in front of the tires rather than offset so far to the inside are they are. From your front view, it looks like the dams are only shielding 1/3 of the tire from the airflow and most of it is shielding the suspension arm (which produces much less drag than the tire). Also you would get better shielding if the inside of the "V" was covered so the airflow can't curl into the space behind the "V".

[majestic]

If you look closely at the Mercedes, there appear to be traditional wheel flaps behind the angled ones. The angled ones are also not vertical to the ground, but angled back as well.

I think the idea is to get a good portion, but certainly not all of the air flowing away from the tires, under the body, and what air is not channeled toward the vehicles center is deflected with the traditional flap.

But the key being the air is directed around or away from the tire. In your first photo, you can see nearly the entire tire is exposed to high pressure flow, and the left side of the "v" (when looking at the photo) almost appears to direct air into the tire.

Part of your problem is not your fault however, your car appears to have a very wide and aggressive stance, as the bumper does not even meet the tire. Your car looks like it might benefit from something like the "reverse mud flaps" seen on the prototype Tesla roadster.

[lunarhighway]

i've though about this problem, the original (non-mercedes-inspired) portion came into existence by asking myself if the size of the factory dam might have been determined by practical considerations such as curb clearence etc (the right side dam had scrup markings on the bottom when i got the car so they're likely as low as the average person would like them) also recents posts sugesting massive airdams could still work had me wondering is perhaps bigger was better.

so i extended the lower portion of the existing dam about 5 cm

you see the original here


my fe seemed to drop off the scale and the car wouldn't coast anymore... so after a few days i decited not to waste any more gass and cut them down a little to their curent form, this improved things although i can't compare to the base level



(truth is i kind of like the look so i didn't want to ditch them right away)

anyway, what i'm considdering now is to do away with the outer portion and go for something like on the tesla. i'll keep the merc dam in place

the tire dams will than deflect the air left and right of the tire, but the merc dams really feel ok for now, coasts and all feel pretty smooth.

this will have some air end up behind the merc-dams, since the merc-dams should create slightly less pressure behind them more air comming of the tires might go on the inside, so the wake on the outside of the tires will be smaller... the net ammount of air that goes into the wheelwells should be about the same because the dams force air that should normally go there to the center of the car (accelerated flow should be lower pressure thus the sort of downforce that makes a car feel a bit more stable)... anyway that's my uneducated theory