silverbullet

Someone pulled up the other day (ironically an off duty cop ) and said that a black puff of smoke comes out the tail during hard acceleration. So I had a friend follow me to observe this. He said that when I shift during a quick 0-100, the puff comes out. Is this something that I should be worried about?! Getting dynoed next week too, so that should help check A/F.

Oh, my mods...
vitesse chip at 16psi
3bar afpr
Tial 38
evo bov
accuboost
cv delete
magnacor wires
and borla catback

Thanks!

fast951

Under load/boost your afr is in the 11.5-12.5:1.. It's normal to see a bit of black smoke.. Of course verify the AFR on the dyno. Before going to the dyno, make sure you have no vacuum leaks (especially under pressure).

silverbullet

Thanks! I thought that alot of people have this (even flames), but I was just curious. The guy who pulled up to me asked if I had a tune up recently, people think somethings terribly wrong.

Oh John, when I get the car dynoed, I'll send you a copy.

Thanks again,
Josh

reno808

If i was you i wouldnt worry that much. It just means that your running rich. Make sure its not to rich.

dime1622

its always natural for a turbocharged vehicle to blow black smoke when an upshift is performed. but an unnecessarily large amount of smoke is a bit of a concern, not because itll damage the motor, but because its hurting your performance and economy.

special tool

On the 951 wedge head, if you don't show smoke, you are not making max power. The 951 makes the most torque at 11.8 - 12 - that makes smoke. You can bring it up to 12.5 to make max HP up high, but you should see some smoke around torque peak.

fast951

Without an AFR it's impossible to tell what is considered too rich or fine.

Again, before going to the dyno, things to do:

- Check the intake pressure side, make sure there are no leaks.
- Check the FQS, make sure it's where you want it based on the FQS settings for your chip.
- check the FPR, make sure there are no leaks and you do have the correct FPR for your chip/FQS

If it all checks out, and if your AFR readings are way off, then something is wrong.

Thank you for the chart.

reno808

O2 sensor??

dime1622

in addition, check your vacuum lines. i was running rich as hell until i fixed them.

ninefiveone

O2 Sensor is ignored at WOT.