After owning my car for slightly less than a week, I finally drove it in the rain. After pulling in to work (I park on the top deck of our garage where nobody parks -- aside from 2 M3s) I noticed two things. The first was a blackish sooty residue on the upper part of the chrome of the exhaust pipes. The second was a slightly dark film (actually looked like dust) on the trunk above the exhaust.

1. Is this normal?

2. Is it an issue of the engine running too rich?

3. Should I check to see if it feels like oil (I don't recall it feeling slippery).

4. What is the best way to clean the chrome exhaust pipes?

For whatever it's worth, I did a lot of idlling in traffic today.

 

the car injects oil into the motor to lubricate things. That oil is burned along with fuel. What you're seeing is the remains of the oil and gas.... it's normal.

I use metal polish to clean the exhaust. Once you do it a few times, the residue wipes off easily.

 

ive never seen it on the top of the exhaust tips, but it builds up on the bottoms for sure, its burnt oil, a necessary process for a rotary engine. I clean it once a week with an old dirty rag, itwipes clean every time. just put the rag between you and the exhaust tip and with a little pressure the smoot comes right off.

 

What's the best way to clean it off the trunk?

 

I have noticed less smoot after M flash. :D I clean it off with Windex on a paper towel.

 

And to think the Renesis is better at emissions than the prior 13B motor. I get a pretty bad buildup on my 93' RX7. Pretty normal for a Rotary.