Little bit of Black...

So, it's a nice sunny day outside today, and I decided to take my Zoe (my 1988 BMW 325is) for a spin. And after I got her nice and warmed up, and ready to go, I nailed it at a stoplight. I noticed, that when I floor it, starting from 0 or like, right at 4k rpms, I notice black smoke/exhaust coming out. But it's only at high rpms, like, around 5500-6k rpms. It'll spit some black "spew" out the back, just like a cloud of black. Not really dark black or anything, but it's noticable. I was just wondering what this is all about. I'd like to know, for I really don't wanna be killing my car. If there is something wrong, which I know there is, then is there any way I can fix it? Any help would be appreciated, thanks!
--Pete

It could be one of the three below... try the technical forums

White Smoke-Very dense, white smoke present in vehicle exhaust gases is symptomatic of transmission fluid being sucked into the engine's combustion chamber and burned. This white smoke is not normal and, if present in the exhaust, generally indicates a problem with the transmission modulator valve. This problem can typically be corrected by replacing the modulator valve.

Black Smoke-Black smoke is the result of partially-burned gasoline being carried down the exhaust. This unburned fuel is wasteful, expensive, and a carcinogen. Black smoke can usually be eliminated with carburetor or fuel injector repairs.

Blue Smoke- Pale, bluish-white smoke is the result of engine lubricating oil being burned in the engine's combustion chamber. The most common causes of blue smoke in the exhaust are worn piston rings or loose valve guides. Both conditions involve major engine repairs to correct. Your mechanic can often diagnose the source of this blue smoke by performing an engine wet/dry compression test.