2014 Audi S4 B8.5 - Mustang AWD Dyno Run - Black Exhaust Smoke

**justr0** · 05-14-2016 07:02 PM

So I put my car up on the Dyno today and saw some strange black smoke coming out of exhaust at high RPM's. The tech's at the shop were suspecting knocking/pre-ignition. But the condition seemed to improve every run, wondering what you guys think might be causing this?

1st run - Lot of black smoke puffs (see video)

2nd run - 1 or 2 puffs of black smoke, followed by 2-3 specks of tiny glowing embers (I do have Cats, so not sure wtf that was)

3rd run - No black smoke at all until the tech let off in the end around 7K rpm.

Car: 2014 Audi S4 B8.5 ~23K mileage
Apr Stage 2 - 93 map
AWE touring exhaust with Res. DP
Injen CAI

I see no fault codes etc., maybe the tune is running rich, but i'm not sure since it seemed like it was getting better every run.

Dyno Results:

**14S4GWM** · 05-14-2016 07:19 PM

No logs during the run?

**rubicant5x** · 05-14-2016 07:28 PM

Your dyno results link is busted

**justr0** · 05-14-2016 07:34 PM

Originally Posted by 14S4GWM

No logs during the run?

Unfortunately no, since the condition improved quite a bit every pull, I didn't bother. I now wish I had.

**MrFunk** · 05-14-2016 07:58 PM

Burning off that carbon!

**sonic32** · 05-14-2016 08:01 PM

Originally Posted by justr0

Unfortunately no, since the condition improved quite a bit every pull, I didn't bother. I now wish I had.

Starting Line NJ? I was there 2-3 weeks ago with my 2012 B8 GIAC St 2 with intake. Mine did the same thing at high rpms, smoke and sparks.

I put down 381whp and 345 wtq on that same dyno.

**justr0** · 05-14-2016 08:22 PM

Yeap, I think you're the one John was telling me about then. He was surprised to see my numbers, they were a bit on the low end for a Stg2 but I think you ran a 93/e85 mix. I saw your dyno run on their Instagram :)

Originally Posted by sonic32

Starting Line NJ? I was there 2-3 weeks ago with my 2012 B8 GIAC St 2 with intake. Mine did the same thing at high rpms, smoke and sparks.

I put down 381whp and 345 wtq on that same dyno.

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**Midnight_Rider** · 05-14-2016 10:07 PM

That is an ugly 4k map.

**KnewJack** · 05-14-2016 11:01 PM

I've never dynoed an S4, but many other cars and black smoke up top usually meant it was getting a bit rich up top. What was the AFR? Computer could have been adding fuel to combat detonation. Any knock retard?

**sonic32** · 05-15-2016 12:02 AM

Originally Posted by KnewJack

I've never dynoed an S4, but many other cars and black smoke up top usually meant it was getting a bit rich up top. What was the AFR? Computer could have been adding fuel to combat detonation. Any knock retard?

I had timing pull up too due to the e85/93 mix I was running. Car could've put down more power.

**sonic32** · 05-15-2016 12:09 AM

Originally Posted by justr0

Yeap, I think you're the one John was telling me about then. He was surprised to see my numbers, they were a bit on the low end for a Stg2 but I think you ran a 93/e85 mix. I saw your dyno run on their Instagram :)

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Yeah but I pulled logs on my 4th run on the dyno and I had so much timing retard that it bumped me down to 93 octane timing. I fucked up the mix that day and got lean codes right before getting on the dyno. I'm gonna go back with a dual pulley and better fuel.