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Discussion Starter · #1 · (Edited)
Anyone have this? I heard going catless will give u black smoke(out of the exhaust) at high rpms since we run rich from the factory?
 

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I've seen catless WRX's - no visible smoke at high-rpm's.
 

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I heard someone mention that if you run catless that the area above your exhaust will turn black from the exhaust gas. Fact or Myth?
 

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I wonder the same thing after seeing an eclipse the other day hammer it and bellow black smoke like crazy.

But... I am running totally catless, and havn't been able to 'see' and black smoke from my tailpipe at all, however I also have a uni-chip, which helps correct the a/f ratio.

I've only had the DP on for a month or so, but havn't noticed soot on my bumber, however, my car is black, so it wouldn't be as noticable on my car as it might be with a lighter color car.

-Jason
 

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If u put around town for a while and then all of a sudden REDLINE her, you'll see a puff of black smoke...black smoke is just carbon deposit stuck in your exhaust...when you see blue smoke is when u should worry (oil burning).
 

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Hey dude... I was wondering the same thing today... when I finally completed my exhaust with the ScoobySport muffer I start ed noticing a lot more smoke...

It's freaking me a little, but I'm not eating oil, my plugs looked fine when I changed them today. I notice if I rev the car, then let off I get smoke, and then it goes right away. I think it's the rich condition, just like between shifts. I really think it's just a characteristic of turbo decatted cars. Someone technical should be able to expand on this.
 

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white or black smoke? I can live with white smoke, black smoke might just make me uncomfortable enough to get a hiflow cat just to get rid of that =\
 

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Looks white to me... but usually white indicates a coolant problem, such as a blown head. I really don't know because I haven't had anyone behind me to identify it... all I know is if I punch it, between shifts there is a puff and it's gone. I'm really not all that worried about it, though I am likely going to get a high flow too until I can tune the car better.

nebix said:
white or black smoke? I can live with white smoke, black smoke might just make me uncomfortable enough to get a hiflow cat just to get rid of that =\
 

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No matter the outcome of a race, you can say "i smoked em" :) (sorry, im a dork)
 

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I have the TurboXS stage 2 on my car and the area above the exhuast has turned black. I just assumed it was running very rich
 

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As mentioned early it is pretty common to get some smoke after mellow driving and then you punch it. I will get a little smoke if I've been driving mellow and then drop a gear a punch it.

About the black build up around the tail pipe thats very common going catless.
 

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Ya I would say if you start losing oil or coolant, or start smelling either burning then worry about it. Otherwise, just keep on truckin!
 

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I have read that black smoke appears at A/F ratio lower than 10:1. A well tuned car should be above that, but I think the ECU pumps some extra fuel in when you make fast throttle transitions. This is just like the accelerator pump on old carbuerators.

I have only seen a couple 12 seconds WRXs. Both of them would spew a small cloud of black smoke on transition to full throttle.

I have seen this same behaviour in a number of other fast cars (mustangs, camaro's, etc). I have a '71 Z28 with a 454 and while I've never seen it, I'd imagine I get a puff of black smoke when I step on it. The 750 CFM Holley squirts tons of fuel during rapid application of throttle.
 

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Doc, how you like that borla exhaust?
 

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pondo said:
Doc, how you like that borla exhaust?

The fit, finish and quality is the best I've seen. I had an Apexi on my last car and it was garbage in comparison.

With all your cats in places it very aggressive sounding. It's probably the perfect exhaust for people who are keeping their cats. Low and burbly while cruising. Loud and aggressive during full throttle.

With no cat's it's pretty loud. It's sounds extremely deep. I personally LOVE it, but I could see where it would be offending to some. I laugh everytime I drive through a parking garage. I set off car alarms all over the floor I'm on (not just in the aisle I'm in).

The tip is perfect size in my opinion. I can't say enough about this exhaust. Not to mention I got mine for like $360 from summit racing. Although I think they have raised the price since then.
 

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thanks for the info man, I was going to get a blitz nur spec but they are soo expensive! I had a borla cat-back on my 3000gt VR4 and it sounded WICKED. Http://vr4.strictly18.com/vr4_idle.MPG <-- movie of her @ idle and revin' to 4 grand
 

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i noticed the rich after rev condition tonite at a local cruise night, i reved to about 5k and watched it fart some rich/ grey smoke then it was fine. dosent smell like coolant, or oil, but hella rich exhaust. i'm running a TurboXS stealth back with a magnaflow tail section.
 

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7.5 year bump.. nice. :rotfl:
 
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