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Exhaust Soot

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#1
Having recently installed a lot of new goodies on my car (intake, exhaust, turbo, tune) I'm having a hard time figuring out what is causing so much exhaust soot on my rear bumper. Okay so I realize that some exhaust soot is to be expected given that I'm running catless, muffler-less (CPE Nexus) and the engine is direct injection, but I think what I'm seeing is cause for concern. The car has 5000km on it, has never been abused, and always used quality fuels. Hopefully someone on here can point me in the right direction.

Kinda tough to capture on film but heres what my entire hatch is covered with:


Garage floor:


I'm leaning towards a small oil leak on the exhaust side of the turbo, but I could be way off. It could also just be the tune that's causing this though. Here's a list of things I plan to check to diagnose the issue:
-Oil level drop? This one may not be of much value with how infrequently I drive the vehicle. At this point, I really only drive it to get new logs for my tuner. Also, as I understand it the car should burn a little bit of oil even when its running correctly.
-Coolant level drop? I seriously doubt that I'm burning/leaking coolant, but I had a comment from a friend who said shortly after start up my car let out a small puff of white smoke, but only once. I'm guessing what he saw was steam being blown out, but you never know.
-Oil leaks! Basically I want to look at every side of the turbo to look for oil. On the intake side, I'll take the elbow off and see if the compressor wheel has extra play in it, any oil on it or has damaged the compressor housing. I'll check the BPV lines for oil, as well as the hot side and cold side intercooler charge pipes for any signs of oil. On the exhaust side, I'll check the DP and turbine for signs of oil as well as look over the exterior of the turbo for any signs of leaks.
-Spark plugs/air filter - I recently swapped to the DENSO ITV22's so I'll pull the plugs and see what they look like. I'll also give the intake filter a look over.
-Cylinder compression test ' From what I've read, blow-by could be the cause of exhaust soot due to oil being burned, worth a shot I think.
- If all tests come back negative, I'll try and drive the car for an extended period of time (~ 1 week) without any WOT, and note the effect on how much soot is on the rear of the car.

Is there anything that I'm missing? The car runs great, and other than the mess on the back of it, I have no reason to suspect a problem. Am I being too paranoid? I just feel like for how few KMs are on the car it really shouldn't be spitting out any oil, or this amount of carbon. Thanks in advance to anyone with some ideas for me.
 


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#2
Rich tune and a catless downpipe will do that. The back of my WRX was peppered with unburnt fuel.

Granted it was quite rich at around 10.4 to 10.6 at full boost.
 


OP
letitreign
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Thread Starter #4
Interesting. I'll take a look at my logs tonight to see just how rich it gets at full boost.
 


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letitreign
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Thread Starter #6
Really? That's comforting to hear, any chance you have pictures?
 


haste

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#8
Same thing happens on my molten orange. Catless with cp-e exhaust.
 


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letitreign
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Thread Starter #11
All of this is making me feel better....perhaps I won't completely tear my car apart lol.
 


OP
letitreign
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Thread Starter #13
On my current tune the richest it gets is 11.32...i think that's fairly standard no?
 


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