Model S Trivia

Model S Trivia

I have a trivia(l) question and I am guessing aerodynamics is the anwer . Why does the dust and dirt seem to be attracted to the back of the car, adjacent to the license plate? The dirt-dust does not gather on the front, roof, trunk, but it sure loves the back. Comments?

Over the weekend we drove our S and stayed at an older hotel that was gracious enough to allow us to charge the car over night. I normally recharge at night at home at 220/40. I reset the charging for 110/20 for. the hotel. I was surprised that it charged at the 12 amps level and it took forever I guess I shouldn’t complain, the hotel did not charge me for charging my car.

portia | 2013年2月3日

yes I noticed too that the back seems to be the dirtiest part of the car.
of course 110v is super slow, 5 miles per hour, that 's what it says on the page
why are you surprised?
but better than nothing if you need it.

Brian H | 2013年2月3日

No steady air flow blowing dirt away there, just little eddies pulling it in and carefully depositing it.

tork | 2013年2月4日

Most 110 outlets are on 15 amp breakers. And you can only draw 80% of that. So 12 amps sounds about right. At least that's what I gathered from previous posts from people smarter than I. I'm not an electrician. If I'm wrong, feel free to correct me!

gregv64 | 2013年2月4日

I don't quite have my model S yet, but it sounds like it doesn't at least accumulate on the rear windscreen? All my previous hatchbacks have had a rear windshield wiper for this reason, but the model S is a bit "faster" than my previous fastbacks (the rear windscreen is less upright).

GLO | 2013年2月4日

I used to have a dieel Mercedes Benz and the area around the license plate was always the dirtiest...I don't think this is just a Model S thing...IMHO.

Brian H | 2013年2月4日

Apparently the airflow over the rear window is fast, and nothing much settles. Part of the design.

olanmills | 2013年2月4日

petero, regarding the dirt, doesn't that happen with all cars?

In the Seattle area, the roads are wet most of the time, but it's not really raining most of the time, so yeah, this crappy dirt just builds up quickly, and it's the worst on the back of the car.

aaronw2 | 2013年2月4日

I have noticed the same thing with my Prius. The part under the spoiler always attracts the most dirt. I think it has to do with the air currents. I actually chose not to install the carbon fiber spoiler on my performance S which might keep it a bit cleaner.

djp | 2013年2月4日

aaronw2 - are you interested in selling your spoiler?

nickjhowe | 2013年2月4日

For those of you that are hand washing your car - something to be aware of. It is even worse than Petero states. The place the dirt REALLY gets is above the license plate under where the chrome strip across the back is. I've hand washed my car several times now, got it spotlessly clean and during the final rinse watched black water run down from above the license plate all over the rear of my white S. It really gets into the nooks and crannies. Make sure you jet it out really well before the final rinse.

jjaeger | 2013年2月4日

I have to agree with petero & nickjhowe. This past weekend hand washed the car and did a complete vacuum, window clean,... When it was all complete went out for a quick 10 mile trip to run an errand. Got back home and not only was the outside of the lower rear area (from the lip above the license plate holder - to the bottom of the car) completely covered in a fine, dark dusting - but what really surprised me when I went to clean it, was when I opened the trunk hatchback, the area at the back where the lid closes to all the way 12+ inches up the two sides was also covered. The amount of this dark dust, and how it had nearly completely covered the back area 'inside and out' was very surprising for such a short trip. Like the panels are charged opposite of the dust and it's just a collector.

Will be interesting to watch if this changes over time.

STEVEZ | 2013年2月4日

The aerodynamic design of the Model S includes a squared-off rear end. There's a dead zone of eddies behind the car that in effect makes the car act like a longer and more streamlined body (i.e., it acts more like a teardrop shape) to the air flowing over the roof, along the sides and (to a lesser extent) under the body. Look at the yarn tufts on the car in this image: see how the ones on the rear are pointing every which way?

Some of the road grime that gets pulled into this dead zone tends to get deposited on the surfaces and there's not enough organized airflow to keep it from settling or to blow it off.

A related note: cars whose rear windows are incorporated into the squared-off tail (most SUVs, crossovers, minivans, etc.) have rear window wipers, by necessity; most sedans with their sloped rear windows don't need wipers back there: the streamlined airflow over the glass keeps water droplets and road grime from settling, when the car is in motion.

Brian H | 2013年2月4日

Ewww. Sounds positively incontinent. Gross.