Facelift S3 Exhaust soot......

Steelster

Steelster

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So, I have read somewhere on here (I think) that the secretion of soot from the exhausts depends on the drive mode and the rev range.

58408d1470677371-building-2017-s3-stunning-mystic-blue-saloon.2.jpg


Using the above picture, from left to right I'll call the tips 1,2,3 and 4. 1 and 2 passenger side, 3 and 4 driver side.

As far as I'm aware, 2 and 3 are the only tips that are going to be collecting soot if you're driving in comfort etc.
Tips 1 and 4 are only active when in Dynamic and at higher rev ranges?! (please correct if I'm wrong)

Recently I've been a lazy git and haven't washed my beauty in what feels like forever. A week or so ago I noticed that tip #1 was showing no sign of soot, whereas all the other 3 were (obviously #2 and #3 had the most).

Has anyone else experienced this? Is this normal?
I rang the service department at Audi and he insisted this is normal, as the outer exhausts are effectively just there for aesthetics.

My query to this therefore, is why is tip #4 collecting soot?

I just wanted to make sure that there might not be a valve stuck or malfunctioning etc which isn't allowing the fumes to flow through all 4 tips. Alternatively (and most likely I suppose) they were correct in the garage and I can ignore this.

Anyone else who drives through the rev range in Dynamic show all 4 tips coated? Am I alone?

:sos:
 
Suppose actual pics of mine might help, even though it doesn't come out as clearly in a photo you should get the idea.

51c1cabb2329ac158bae17c003402092.jpg


The side which concerns me.....
f819eac62dea5a4e0479ef9510780b5c.jpg


Other side for comparison.....
5eb378f0611ddec088163be748327740.jpg
 
Mine regularly sees the top end of the rev range and
- pipes 2 & 3 only get dirty when giving it some
- pipes 1 & 4 take a while to show soot particularly if driving sensibly but absolutely will eventually show some, me thinks you were being fobbed off

Your pipe 4 does look grubbier than my pipe 4 ever does but based on your photos and assuming the car is running fine I would forget about it and just drive it.

My pipes still look like new at 3years and 24k miles, baby wipes are the answer ;)
 
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msdmjb said:
Mine regularly sees the top end of the rev range and
- pipes 2 & 3 only get dirty when giving it some
- pipes 1 & 4 take a while to show soot particularly if driving sensibly but absolutely will eventually show some, me thinks you were being fobbed off

Your pipe 4 does look grubbier than my pipe 4 ever does but based on your photos and assuming the car is running fine I would forget about it and just drive it.

My pipes still look like new at 3years and 24k miles, baby wipes are the answer ;)
Click to expand...
Thanks! I plan on leaving it dirty another week or so and giving her a little extra (safely of course) and see if anything builds up.

I use autosol to get mine gleaming, hate seeing her dirty but given the amount of leaves blowing around I can't bring myself to spend hours cleaning when I know I won't be able to tell a few hours later.
 
Since doing the exhaust flap VCDS mod, all 4 of mine are evenly sooted. Before doing the mod, as expected, 2 and 3 were black as the night and 1, 4 were pretty clean most of the time.
 
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I've had my flaps open from quite early on but when I see most other S3s the tips are always unevenly sooted. Mine are quite consistent.
 
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Steelster said:
So, I have read somewhere on here (I think) that the secretion of soot from the exhausts depends on the drive mode and the rev range.

58408d1470677371-building-2017-s3-stunning-mystic-blue-saloon.2.jpg


Using the above picture, from left to right I'll call the tips 1,2,3 and 4. 1 and 2 passenger side, 3 and 4 driver side.

As far as I'm aware, 2 and 3 are the only tips that are going to be collecting soot if you're driving in comfort etc.
Tips 1 and 4 are only active when in Dynamic and at higher rev ranges?! (please correct if I'm wrong)

Recently I've been a lazy git and haven't washed my beauty in what feels like forever. A week or so ago I noticed that tip #1 was showing no sign of soot, whereas all the other 3 were (obviously #2 and #3 had the most).

Has anyone else experienced this? Is this normal?
I rang the service department at Audi and he insisted this is normal, as the outer exhausts are effectively just there for aesthetics.

My query to this therefore, is why is tip #4 collecting soot?

I just wanted to make sure that there might not be a valve stuck or malfunctioning etc which isn't allowing the fumes to flow through all 4 tips. Alternatively (and most likely I suppose) they were correct in the garage and I can ignore this.

Anyone else who drives through the rev range in Dynamic show all 4 tips coated? Am I alone?

:sos:
Click to expand...
Mine are exactly the same as yours. If you leave your car in P start the engine and then select DYNAMIC and go to the back you will find that the valves in Pipe 1 and 4 are open. If you place your hand over each pipe in turn you will feel the exhaust gases escaping.
 
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Looking at that it looks like the flap in pipe 4 is stuck open.
Like paradigital above, before I had my flaps coded open, only pipes 2 and 3 had any soot on them. Now they hardly soot up at all but are even across all four.

A scan with VCDS should show if there is a fault.
 
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I have the same tip 1 that stays clean. I have done a test in sport dynamic While parked, with a flexible long spring that I put in all the pipes and they are all open. And in comfort mode 1 and 4 are closed. So I 'm wondering what it could be so that the first tip stays clean.

S3 sportback 2017 daytona
 
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computeratelier said:
I have the same tip 1 that stays clean. I have done a test in sport dynamic While parked, with a flexible long spring that I put in all the pipes and they are all open. And in comfort mode 1 and 4 are closed. So I 'm wondering what it could be so that the first tip stays clean.

S3 sportback 2017 daytona
Click to expand...
Was interested in doing a similar test to see if Carista really opened my valves correctly or not.

How far 'in' does the pipe get shut when the valve is shut please? Roughly..
 
azibux1 said:
Was interested in doing a similar test to see if Carista really opened my valves correctly or not.

How far 'in' does the pipe get shut when the valve is shut please? Roughly..
Click to expand...
I had my S3 parked in my garage with the door open. When Dynamic mode is engaged you can hear the valves opening. With the engine running you can feel the exhaust gas leaving the pipes. If you really must check tape some flexible plastic straws together and that will be plenty long enough, do not use anything sharp or to stiff
 
GW1 said:
I had my S3 parked in my garage with the door open. When Dynamic mode is engaged you can hear the valves opening. With the engine running you can feel the exhaust gas leaving the pipes. If you really must check tape some flexible plastic straws together and that will be plenty long enough, do not use anything sharp or to stiff
Click to expand...
I did check with my hand / a plastic cup if I remember correctly (to see it steaming up) and it did seem all were open but some seemed slightly more than others - I guess that's just the nature of the path that the air takes, can't expect them to all be identical 100%
 
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azibux1 said:
Was interested in doing a similar test to see if Carista really opened my valves correctly or not.

How far 'in' does the pipe get shut when the valve is shut please? Roughly..
Click to expand...
If you look under your car you can see the valve in pipe 1 and 4 so you can measure how deep

S3 sportback 2017 daytona
 
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azibux1 said:
I did check with my hand / a plastic cup if I remember correctly (to see it steaming up) and it did seem all were open but some seemed slightly more than others - I guess that's just the nature of the path that the air takes, can't expect them to all be identical 100%
Click to expand...
You are correct. One factor as to why there is less exhaust gas movement from both the outer pipes is that the butterfly valves inside the system cause a restriction to the gas flow. The other factor is that all four tailpipes exit from a single exhaust box and the gas will take a path of least resistance that is also why there is less exhaust existing the two outer pipes.
 
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GW1 said:
You are correct. One factor as to why there is less exhaust gas movement from both the outer pipes is that the butterfly valves inside the system cause a restriction to the gas flow. The other factor is that all four tailpipes exit from a single exhaust box and the gas will take a path of least resistance that is also why there is less exhaust existing the two outer pipes.
Click to expand...
Ok but why is there a big difference between the left and the right outer pipe.

S3 sportback 2017 daytona
 
audi upgrades
computeratelier said:
Ok but why is there a big difference between the left and the right outer pipe.

S3 sportback 2017 daytona
Click to expand...
As I explained the two outer pipes have a restriction caused by the butterfly valves inside the pipes they are not exactly free flow. There is a single box that the four tailpipes exit from, this box has a volume that exceeds the total exhaust generated by the engine. When you exceed approximately 4K revs the two outer butterflies open and allow exhaust gases to pass but not by a an equal division this being caused as I have already said by the restriction caused by the butterflies.
 
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audi upgrades
Should there be flow from all 4 pipes if the car is idle without disconnecting valves?

I've just disconnected my valves but can't hear any extra noise, in fact feels like i may have closed them by accident. However put car in efficiency and parked up, flow from all 4 pipes. Is this normal or would there only be flow from 2 pipes usually?
 
Put it into (S) sport mode on the transmission. The exhaust valves will open then at idle with an increased RPM also. Dynamic mode also does this on a warm engine.
 
Last edited:
Flying Scotsman said:
Put it into (S) sport mode on the transmission. The exhaust valves will open then at idle with an increased RPM also. Dynamic mode also does this on a warm engine.
Click to expand...
But that would happen without disabling valves? I'm unsure if mine have opened or not but my question is that on efficiency and idle, there's flow from all 4 pipes. If i hadn't disabled valves, would there still be flow from all 4 or just 2?
 
I should have read the full thread, my apologies. If there is flow from all 4 pipes you have disabled the valves in the open position, regardless of mode selection. Normal operation with operating valves is flow from 2 pipes, one on the left bank and one on the right bank at idle, and then open the 2 valves at about 3,500RPM unless you use S or dynamic mode and then they will open at idle and remain open through the full RPM range, as I noted on, in my previous post.

Edit, I just read your post on another thread on "all pipes operating" and you state that when you put it into efficiency mode, you then get all 4 pipes operating. This makes no sense. How have you disconnected the valves?
 
Last edited:
Does no one clean their exhausts thoroughly? I keep mine spotless so the sooting issue isn't a problem

I have since changed my exhaust to a milltek so "sooting" is now even
 
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Flying Scotsman said:
I should have read the full thread, my apologies. If there is flow from all 4 pipes you have disabled the valves in the open position, regardless of mode selection. Normal operation with operating valves is flow from 2 pipes, one on the left bank and one on the right bank at idle, and then open the 2 valves at about 3,500RPM unless you use S or dynamic mode and then they will open at idle and remain open through the full RPM range, as I noted on, in my previous post.

Edit, I just read your post on another thread on "all pipes operating" and you state that when you put it into efficiency mode, you then get all 4 pipes operating. This makes no sense. How have you disconnected the valves?
Click to expand...

Okay that's great thanks for that! I am getting flow from all 4 pipes regardless of mode selection.
I put the car in sport/dynamic and turned the car off, then removed the valve cables.
 
Mine is exactly the same tip #1 is pretty clean compared to the rest. Audi inspected it for me and the valves were opening correctly, so I guess nothing to worry about. The strange thing for me is that I had a PFL and it didn't do it but this new FL car does. On the old car both tip 1 and 4 would soot equally.
 
Same as others here, however clean mine weekly with autosol metal polish so never let it get to a "bad" state.
 
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