What causes the black smoke (carbon?) to come from the muffler?

[ohioan]

When you floor it in a situation like, going 40mph and then dropping to 3rd and hammering it?

I heard that it's "good" for the car sometimes becuase it gets old crap out of the exhaust. Anyone know the reason that this is caused? Bad o2 sensor or something? Or is it normal?

wiki says: Rich
It means that the system is running rich, in other words too much fuel.




Hey,

Try checking your air filter--make sure it is not dirty. Also check for a plugged air intake hose. Enough air is not getting into your cylinders for the proper air-fuel ratio.

Good luck.

 

[mndsm]

Completely normal. Car runs pig rich from the factory, when you initially stomp the throttle. ECU sees that the car went to WOT, and dumps fuel before the turbo has a chance to catch up.

 

[hugador]

It is normal. Our cars run rich. Stock tune afr will drop in the 9s which is very riich.

 

[lynnriderm6]

you would rather see black smoke then white.....car runs to lean means zoom zoom boom!

 

[BigDaddyMS3]

Rich

The factory tune is RICH! Just carry a damp rag in the hatch and wipe down after every gas station fill-up.

 

[bykeryder4life]

as said already the factory tune is pretty darn rich. Also, there has been guys on the other forums that hooked scopes up to the injectors and found that at higher rpm's they spray into the exhaust stroke a little bit, causing extra fuel to go out the exhaust and get more soot on the tailpipe as a result

 

[ohioan]

I have tons of soot on the tailpipe. I think the previous owner must have gunned it a bunch (don't blame him either

Gotta find some cleaner. My pipe is black!

 

[SBSPEED3]

totally normal, and imo a good thing. lean+boost= a very bad day. soot can be a bit of a pain, but id rather have a dirty bumper than a blown motor.

I have tons of soot on the tailpipe. I think the previous owner must have gunned it a bunch (don't blame him either

Gotta find some cleaner. My pipe is black!

try waxing the tailpipe next time you detail the car. this will prevent the soot from sticking as much, and makes cleaning easier for a while.


on a different note, i heard someone say the other day that a SRI would cause the motor to lean out, is this true? i can understand that it would due to more airflow into the engine, but i figured the MAF would keep AFRs the same as stock...

 

[hugador]

totally normal, and imo a good thing. lean+boost= a very bad day. soot can be a bit of a pain, but id rather have a dirty bumper than a blown motor.



try waxing the tailpipe next time you detail the car. this will prevent the soot from sticking as much, and makes cleaning easier for a while.


on a different note, i heard someone say the other day that a SRI would cause the motor to lean out, is this true? i can understand that it would due to more airflow into the engine, but i figured the MAF would keep AFRs the same as stock...

Fuel trims does change more notable LTFT. But nothing too dramatic to worry about.

 

[SBSPEED3]

awesome, thanks for the response

 

[hugador]

awesome, thanks for the response

Every brand intake are made different. Thats why fuel trims are different from others with a different intake.

 

[mortimersnerd]

The intake diameter is slightly larger, so the MAF underreports the amount of air, causing it to lean out a little. This is true even for the Mazdaspeed (AEM) intake, so don't sweat it.

 

[amascio]

If the stock tune wasn't rich

and instead Mazda tried for stociometric ratio, you could casually drive your car and have a white hot turbo. The up side of that would be you could completely cook a 10 lb brisket on your way home from work. Now THATS multitasking your car to the point of being "green".

 

[matsuda]

on a different note, i heard someone say the other day that a SRI would cause the motor to lean out, is this true?

No.

i can understand that it would due to more airflow into the engine, but i figured the MAF would keep AFRs the same as stock...

True (assuming the fuel trims are set).

 

[matsuda]

...and instead Mazda tried for stociometric ratio, you could casually drive your car and have a white hot turbo.

The MS3 is no different than most cars in that the AFR is stoich at idle and cruise. The difference is that the MS3 runs richer than most cars at WOT.

 

[gogogomoveit]

That is probably the difference between MZR-ZDT direct injection turbo engine against others. It runs very rich to protect the engine during transition from lean burn mode to a WOT situation.

 

[ohioan]

Well, I like that it protects itself from damage. I'll take the black smoke, or at least the car behind me will