I just purchased a new to me used 2011 JCW Mini Cooper Hardtop.

The car has 20,000 miles on the odometer and per the seller no modifications have been done.

I drove the car home today with my friend following. I accelerated pretty hard and shifted, at which point my friend behind me noticed black smoke was coming out of the exhaust during the shift.

Additionally, I stayed in a gear like 4th and mashed the throttle and the same thing happened again.

What can be causing this, and is it normal?

I don't know if the car has any ECU based modifications but I doubt it. I was wondering if there is any real way other than taking it to the dealer to check to see if the ECU has been modified with a chip? I hope it doesn't as this would void the warranty if I attempted to take it into service and I want to avoid any issues.

Thanks!

 

How much black smoke are we talking about here? My brand new MCS makes enough while the turbo is spooling up to be seen in headlights of cars behind me at night through my rear view mirror. Every turbocharged car I've owned has too, more or less. Keeping EGTs down requires pretty rich AFRs on engines with forced induction. This often results in some amount of smoke. On the other hand, a failed turbo oil seal can also produce smoke.

Is it a puff or a cloud?

--Matt

 

Hmm I think it's a puff. I need to drive around again and have someone monitor it..

 

Black smoke normally indicates carbon buildup. Usually it means that the car hasn't been driven hard often. I see it every once in awhile on the freeway.

 

They may be commonly seen together, but one certainly doesn't necessarily indicate the other. As I mentioned, my '13 smokes a bit under acceleration. It only has 6k miles, so I'm certain it isn't related in my case. There are plenty of reasons for black smoke that don't have anything to do with carbon buildup.

--Matt

 

There aren't all that many reasons for black smoke. It could be a situation when the engine is running extremely rich.

 

Not owned many turbocharged vehicles eh? I haven't owned a single one that hasn't made some smoke, under some circumstances at least. "Extremely rich," as you state it anyways, is where they run to keep cylinder temps down. Many modern tuned turbo engines run AFRs that dip into the 10s, some even lower, and a bit of smoke is completely normal and not at all unexpected. These engines dip deep into the 11s stock when new and into the 10s with aftermarket tunes, so they're certainly no exception.

Black smoke on a turbocharged engine is not necessarily an indicator of anything being wrong, especially when it's just a puff at WOT. As long as it is not white smoke, blue smoke, or a constant plume of smoke its probably OK.

--Matt

 

If you have any doubts on the car, its still under warranty as its only 20k miles and a 2011. Have the dealer give it a check.