I notice my Z would get this black exhaust residue at the bottom of my exhaust tips (basically the lower tip of the outlet). I clean them when I wash the car. After awhile I still get it. Is this normal or has anyone have this issue also? I've had the car since February.

 

Everyone gets it - perfectly normal. Keep on doing what you're doing. If it gets bad you can use some metal polish, but if you keep it clean it shouldn't be necessary.

 

Thanks for the info. I did a search and notice that some people use "Never-Dull" (Nevr-dull). Does anyone know if this is available in any walk-in stores. I did find a bunch of places selling it online.

 

Available everywhere, from pep-boys to wal-mart.

 

That's not true.. Its the type of oil you use.... Use Castrol full syntetic oil... and it wont happen again.

 

Oil type has nothing to do with the carbon deposits. I use Amsoil ASL 5W30 full synthetic, my car burns zero oil in 6000 miles and I still get the carbon on the mufler tips.

It is caused by the front cylinders going 30% rich at WOT and high RPMs. The intake manifold slopes down at the front to clear the strut tower brace and does not flow as much air to the front cylinders. There is an aftermarket manifold and strut tower mod available which also improves power. There may still be a little carbon because the Z runs prettty rich at WOT.

 

Im sorry to say this but that is not true and have 3 cars that I can say that it took care of this. I have a 96 Ford F150 and the exhaust was always wet... I changed oil brands to CASTROL and it is so dry, I can take a picture right now for you and you will see how rusted the exhaust pipe is because of that... I did it for the Honda CRV which I can also take pictures and same results!! So I do it on my 350z and the exact same thing, my exhaust is OIL FREEE and clean. And this was the only thing done to the cars, I have also reffered this to others and same results. I don't know what it is, but some reason Castrol doesn't burn as much oil?? I have no idea what it is...

 

You should sell your car back to Nissan so they can reverse-engineer your miracle exhaust!

 

I've tried different brands of regular oil on my 95 Maxima. I've never noticed any carbon deposits at the tip of my aftermarket Greddy exhaust. I'll try Castrol and see how it goes next time on the Z. But I think it's probably just a characteristic of this car.