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Mystery of Rear Bumper Dust



Attention all space shuttle engineers: Why is it that after I drive the 1.8 miles home from the car wash there is already a LARGE layer of dust on top of my bumper? There is never dust anywhere else on the car for at least 1/2 an hour but the back bumper is covered INSTANTLY. Does it have to do with the air coming under the wing or some whirling vortex behind the car? Is it my imagination or does anyone else (especially with a black NSX) notice this???????
<< Is it my imagination or does anyone else (especially with a black NSX) notice this??????? [/B][/QUOTE]

Trust me it is very very real .... LOLL

98-T Black/Tan one of 5 only!
Happens with a lot of cars, too. Not just the NSX.

It has to do with aerodynamics. What would be interesting is to see if the Taitec rear diffuser helps at all. =)

I get it all the time that's why I keep a California Duster in the trunk.

Steven 91 Blk/Ivory
Originally posted by Black&Tan97Tnewportbeach:
Why is it that after I drive the 1.8 miles home from the car wash there is already a LARGE layer of dust on top of my bumper?

It's cause by the vortex. Your driving too slow!
You need to go faster so the vortex is moved behind the bumper...
Tell me if this works with the cops okay.

I have a Black too and it drives me crazy. But I think dusting my car and washing my NSX every time I drive it is making my wife crazier!
Originally posted by DanO:
It's Yoko dust. <g>

Speaking of dust, I was changing out the rear taillights for the Japanese versions with the help of a fellow NSX friend. Once they were out, I was wiping the taillight area clean and then saw a ton of dust on the inside portion of the quarter panel area. I was going to wipe it clean and he said, "No No No No! Leave it there! Don't wipe it clean. It's Tochigi dust!" It's still in there to this day.


[This message has been edited by Vytas (edited 08 January 2002).]
yoko,ono, very funny....

as part of you anal retentive types therapy i recommend a regimen of

no waxing or cleaning for one year

a quick trip to the 100$ repaint body shop every 18months

sell your cars to me every four years... i promise ill give you a fair price for your newly repainted nsx.

i currently own a black nsx and highly recommend my advice
So nobody has any ideas? I too get TONS of this black soot all over the upper side of my rear bumper. It's really dark and will turn a white towel + quick detailer pitch black. None of my other cars have this problem.
HEY !! I thought I was the only one with this problem. It drives me nuts. I drive to work all clean and shiney and arrive home with all this black soot on the rear bumper.

Also, you can't just wipe this crap off. I wind up "chasing" it around the whole rear end and spreading it.

I'm convinced that its mostly rubber from the "scrubbing" alignment setting of the rear tires. I'm presently working on a process to reconstitute the rubber dust into new rear tires so that I don't have to buy them so often. Any investors?
I think its from the exhaust. When my car blew a coolant hose, all of the coolant actually went under the car, and then due to some aerodynamics went Back on TOP of my car.
The air traveling from under the NSX actually loops back around to the top of the car. Hence, any dust, and exhaust and whatnot will loop back onto your bumper while driving. Something that doesnt happen with any other part of the car.
Solution? Taitec Rear Diffuser.
I believe it is also a build up of the dust/dirt you drive through...i guess the way the wind goes over/around the car it never hit the top of the bumper. Washed my car today and due to the construction in my new subdivision, once i got back i had a layer of brown dirt on my rear bumper.

92 Red/Blk
This issue is also related to the brand of tire. When I had OEM Yokos, after washing my car, the first drive produced both fine light-colored particles (dirt) and larger obvious black particles. When I installed Dunlop 9000's, the bumper accumulated fine particles only. Because the rear Yokos are soft and disintegrated rapidly (~5K miles) and Dunlaps are harder and will last 3-4 times longer than Yokos, these observations are consistent with the generation of an underbody vortex that deposits both road dust and tire leavings on the rear bumper. In conclusion, although the Yokos give much better steering characteristics than the Dunlaps, the Dunlaps keep the car looking cleaner and longer than the Yokos (and are much quieter too).

95 NSX-T, 5 sp, Red/Tan, Stock, except Dunlaptya SP9000s
My guess would be it is all brake dust. It appears to have a metallic sparkle when viewed from different angles. I hope my engine is not discharging fine particles of metal.

As far as this stuff sticking to the bumper, there is a lot electrostatic build-up from the plastic the bumper is made from.

97-T #009