i know i've asked this before but now im really wondering what is wrong wit my ss s/c. i get tons of black smoke coming out of my car shifting @ 4000 rpms and when i downshifts it takes a second or 2 before the supercharger starts whining and gets it's act together. I just recently did an oil change but im thinkin whoever did it, never did a good job. Wonderin' what else it could be??

 

What are your mods?

 

None of the problem you have described are related.

When you downshift, you reduce engine RPM, and hence supercharger RPM as well, so it is going to reduce output until you accelerate to a higher RPM again. That sounds normal.

Black smoke from the exhaust is an indication of a rich mixture. Normally this would be accompanied by a CEL, but since it isn't, and you only get it during a specific kind of shift, you are probably just making a very aggressive throttle change resulting in a little extra unburnt gas being sent through the the engine to prevent a lean spike and keep the engine smooth during the sudden throttle movement. That also is normal for the car, but it's the car telling you to use the accelerator a little smoother, instead of full open to full closed.

Burning oil is blue smoke. So your oil change had nothing to do with it.

 

It Seems I am always washing the carbon off the back of my car !!!
Becasuse of it being yellow it really shows up.

 

i have no mods to the car, its back to stock and this use to never happen, only when i keep my foot on the gas and hit the rev limiter. So i'm thinkin it's not normal since it will do it after 4000 rpm's or when i downshift and the car also when u rev to the limit and change gears and put ur foot on the gas again, it jerks 4 a bit then it starts picking up but jerks even more and doesn't go to its fullest anymore.

 

Lesson #1 why you don't hit the rev limiter. It is there for a reason. If you keep bouncing off of it something has to give.