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Old 02-15-2009, 02:31 AM   #1
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Default Does your car black smoke in boost?

So.... When I ran 12.5:1 AFR's it didn't smoke in boost, or at least not noticeably from driving and nobody ever told me it did. But with my car tuned to 11.5:1 in full boost, I can see a decent amount of black smoke coming out the back. I don't have a catalytic converter. Motor runs strong as hell, no knock, never uses oil ever at all whatsoever not even a spec or an infinitesimally small amount. But it black smokes in full boost. Like a diesel with a programmer, but not a sever obviously. Just wondering if I'm alone.

Do you have a catalytic converter?
What AFR do you tune for in full boost?
Any visible smoke at full boost?
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Old 02-15-2009, 02:44 AM   #2
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No cat.
12:1 & 11.8:1 above 14 psi
No visible black smoke at full boost but I do get some soot on my bumper so there must be some. The small black specks **** me off most.
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Old 02-15-2009, 09:39 AM   #3
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Has cat. No visible, but the tail pipe is black. I think those specs come from a collection of particulate in the exhaust that breaks loose. I get it, though not bad.
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Old 02-15-2009, 12:53 PM   #4
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I haven't seen soot out of mine even running slightly richer than I was (high 11s at 9 psi).

I have no clue if my bumper is black. but that's more from rich idle since the flow velocity at speed is high enough to keep it off your car. note: i idle at 14.3:1.
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Old 02-15-2009, 12:59 PM   #5
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You are running a cat still though aren't you Y8s?
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Old 02-15-2009, 01:10 PM   #6
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Yep....

Name:  Smoke12.jpg
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Old 02-15-2009, 01:16 PM   #7
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Quote:
Originally Posted by y8s View Post
I haven't seen soot out of mine even running slightly richer than I was (high 11s at 9 psi).

I have no clue if my bumper is black. but that's more from rich idle since the flow velocity at speed is high enough to keep it off your car. note: i idle at 14.3:1.
you saw some out of mine that one time right? but i have no cat...
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Old 02-15-2009, 05:02 PM   #8
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Could be accel enrich as well if the black smoke is only short. I'd be more worried about blue smoke...
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Old 02-15-2009, 05:14 PM   #9
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Quote:
Originally Posted by Spookyfish View Post
Could be accel enrich as well if the black smoke is only short. I'd be more worried about blue smoke...
Nope, it's just the tune. Just curious if everybody has this to some extent. I never noticed till yesterday when I decided to look in the rear view mirror during full boost. Scary to take your eyes off the road when in full boost. I did a few 2nd and 3rd gear pulls and it's pretty repeatable.
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Old 02-15-2009, 05:17 PM   #10
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Rear mount cam... may try this tomorrow...
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Old 02-15-2009, 05:21 PM   #11
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11.0:1 at high RPM and no black smoke here. I have video of 4-5-6 pulls to redline in 6th and there's nothing from my tailpipe. This was with a cat, though.
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Old 02-15-2009, 05:23 PM   #12
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YouTube - Escort GTR Turbo - dyno's 241 hp / 244 tq

this was shortly after i upped the boost from 9psi to 18psi... REALLY conservative tune, like high 10's AFR. no visible smoke (exhaust exits next to passenger side tow hook)

i do have a cat.
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Old 02-15-2009, 05:45 PM   #13
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I've noticed it on mine and I've noticed it on brand new modified cars as well. Black is okay as far as i can tell.
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Old 02-15-2009, 06:12 PM   #14
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No visible black smoke, plenty of soot on the bumper between washes. 11.5:1 in boost, no cat.
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Old 02-15-2009, 08:44 PM   #15
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No black smoke here at 11.5:1 in boost. No cat either.
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Old 02-15-2009, 09:58 PM   #16
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I guess mine's special. Guess I could datalog it just to make sure it's running 11.5 and not richer. Need to hook up my AFR gauge one day.
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Old 02-16-2009, 12:07 AM   #17
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Quote:
Originally Posted by cjernigan View Post
You are running a cat still though aren't you Y8s?
I am running a cat...

but you've all seen the AFR readings on the dyno... they exactly match the onboard wideband. even with the cat. over 3000 rpm, it's not doing much.
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