2007 Audi S6 – Carbon Buildup – Dyno
12-14-2010, 07:48 AM
#21
AudiWorld Senior Member
I was looking around the web at boroscopes. Seems like for under $150, it would be a great inspection tool to have around - to quickly and easily monitor carbon buildup.... and to document it as needed.
I am not sure how to do the inspection (yet :-)), but I do read that this is the way to inspect for carbon build up.
I am worried about my S6 now, and am thinking it would be good to have a non-invasive way to check / monitor it.
Thoughts?
I am not sure how to do the inspection (yet :-)), but I do read that this is the way to inspect for carbon build up.
I am worried about my S6 now, and am thinking it would be good to have a non-invasive way to check / monitor it.
Thoughts?
12-14-2010, 08:27 AM
#22
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My service rep told me he was doing me a favor by doing the decarb cleaning. I am not sure what that means and whether or not I would have had to pay for it otherwise.
Again, Audi does not see the power loss as being an issue and will not take care of the problem simply because it is there. Audi and the dealer will only act on it if there is a code thrown and if the car is still under warranty.
I suspect I was driving with 55 less wheel HP for quite some time now. And just to put this in perspective, 55 AWHP is about 70 HP to the crank. Now subtract 70 from 435 and you get 365... so basically my S6 with carbon buildup had as much power as a regular 4.2... makes me sick.
Again, Audi does not see the power loss as being an issue and will not take care of the problem simply because it is there. Audi and the dealer will only act on it if there is a code thrown and if the car is still under warranty.
I suspect I was driving with 55 less wheel HP for quite some time now. And just to put this in perspective, 55 AWHP is about 70 HP to the crank. Now subtract 70 from 435 and you get 365... so basically my S6 with carbon buildup had as much power as a regular 4.2... makes me sick.
12-14-2010, 04:44 PM
#23
AudiWorld Super User
This is not a fair comparison. The VW was not an FSI engine. The fuel injection in the VW occurs in the intake manifold so that the fuel passes over the valves and the detergent in the fuel keeps the valves clean. An FSI engine injects directly into the cylinders and therefore there is no flow over the intake valves.
As a side comment - You really should be running higher octane gas in your turbo. I suppose the knock sensors may keep you from destroying your engine but you are losing a lot of power. Turbos can really benefit from higher octane.
As a side comment - You really should be running higher octane gas in your turbo. I suppose the knock sensors may keep you from destroying your engine but you are losing a lot of power. Turbos can really benefit from higher octane.
My now gone 1987 5000CStq had 286,000 on the clock when I donated it (bought it new and had it for 18 years). Premium was recommended but I maybe filled it a dozen times with the good stuff. That saved me almost $3k over the life of the car. I feel that with knock sensors, buying premium is a waste unless you are racing. The .2 sec 0-60 loss is not worth it to me. For my current 2004 A8 w 4.2L (non-FSI) engine, I did several tests of fuel eCONomy and the increase in fuel eCONomy was not worth even 3¢ let alone the 20¢ difference in fuel cost.
All IMHO.
I guess the FSI vs non-fsi means little to me other than in the case of V-8 engines, FSI engines get better fuel eCONomy and they don't have a timing belt which would make the FSI engine first choice for me.
12-14-2010, 05:50 PM
#24
AudiWorld Super User
Thread Starter
I'm sure you realize that our main concern here is not fuel economy. We are on a different side of the fence where performance is what concerns us. I burn through gas like water and as long as my car functions the way it was intended to is all that matters to me.
At 20¢/gallon difference, It ain't worth it to me. I accelerate to 70 or 80 mph just fine. So far, for 103,000 miles I've saved at least $750.00
My now gone 1987 5000CStq had 286,000 on the clock when I donated it (bought it new and had it for 18 years). Premium was recommended but I maybe filled it a dozen times with the good stuff. That saved me almost $3k over the life of the car. I feel that with knock sensors, buying premium is a waste unless you are racing. The .2 sec 0-60 loss is not worth it to me. For my current 2004 A8 w 4.2L (non-FSI) engine, I did several tests of fuel eCONomy and the increase in fuel eCONomy was not worth even 3¢ let alone the 20¢ difference in fuel cost.
All IMHO.
I guess the FSI vs non-fsi means little to me other than in the case of V-8 engines, FSI engines get better fuel eCONomy and they don't have a timing belt which would make the FSI engine first choice for me.
My now gone 1987 5000CStq had 286,000 on the clock when I donated it (bought it new and had it for 18 years). Premium was recommended but I maybe filled it a dozen times with the good stuff. That saved me almost $3k over the life of the car. I feel that with knock sensors, buying premium is a waste unless you are racing. The .2 sec 0-60 loss is not worth it to me. For my current 2004 A8 w 4.2L (non-FSI) engine, I did several tests of fuel eCONomy and the increase in fuel eCONomy was not worth even 3¢ let alone the 20¢ difference in fuel cost.
All IMHO.
I guess the FSI vs non-fsi means little to me other than in the case of V-8 engines, FSI engines get better fuel eCONomy and they don't have a timing belt which would make the FSI engine first choice for me.
12-14-2010, 06:51 PM
#25
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2 Stroke background!!!!
The images in your thread makes me think back 40+ years when I took off the head of the old DKW 3=6/Auto Union 1000 Sp 2 stroke engines, and even those weren't as bad as most of those you have here!!!!
So here's a question for you: are you using synthetic oil? and/or any gas additives to clean exactly those intake and valves buildup you show?
I normally do injection cleaners from new as I don't believe that gas contains enough cleaning agents to do the job, and I don't refer to AUDIs but any car in particular. I also go synthetic after 10K, but I have no clue if that would make any difference in cases as bad as the ones you have shown here.
These images makes me want to delay my decision to get a new AUDI!!!
So here's a question for you: are you using synthetic oil? and/or any gas additives to clean exactly those intake and valves buildup you show?
I normally do injection cleaners from new as I don't believe that gas contains enough cleaning agents to do the job, and I don't refer to AUDIs but any car in particular. I also go synthetic after 10K, but I have no clue if that would make any difference in cases as bad as the ones you have shown here.
These images makes me want to delay my decision to get a new AUDI!!!
12-15-2010, 01:31 PM
#26
AudiWorld Super User
Thread Starter
Even the R8 has this problem and apparently known by media:
http://www.r8talk.com/forums/showthread.php?t=4403
http://www.r8talk.com/forums/showthread.php?t=4403
12-15-2010, 01:41 PM
#27
AudiWorld Super User
Thread Starter
VW patent acknowledging the intake valve deposit issue.
Directly from the technical staff of VAG is complete acknowledgment of the FSI intake valve deposit issue, and it's impacts, including: decreased performance, misfires, catalytic converter damage... etc.
"Gasoline engines with direct injection of the fuel into the combustion chamber, i.e., not into the intake port, suffer especially from the problem of the formation of carbon deposits on components. Carbon deposits form especially in the neck region of intake valves. A more exact analysis of how these carbon deposits form leads to the following result: Oil and fuel constituents first form a sticky coating on the components. These constituents are chiefly long-chain and branched-chain hydrocarbons, i.e., the low-volatility components of oil and fuel. Aromatic compounds adhere especially well. This sticky base coating serves as a base for the deposition of soot particles. This results in a porous surface, in which oil and fuel particles in turn become embedded. This process is a circular process, by which the coating thickness of the carbon deposits continuously increases. Especially in the area of the intake valves, the deposits originate from blowby gases and from internal and external exhaust gas recirculation, and in this process, the blowby gasses and the recirculated exhaust gas come into direct contact with the intake valve."
"Especially in the area of the neck of the intake valves, excessive carbon deposits have extremely negative effects for the following reasons: In the case of Otto direct injectors, the successful ignition of the stratified charge depends to a great extent on the correct development of the internal cylinder flow, which ensures reliable transport of the injected fuel to the spark plug to guarantee reliable ignition at the spark plug. However, a coating of carbon deposits in the neck region of the intake valve may interfere so strongly with the tumble flow that ignition failures may occur there as a result. Under certain circumstances, however, ignition failures can lead to irreversible damage of a catalytic converter installed in the exhaust gas tract for purifying the exhaust gas. Furthermore, the coating of carbon deposits in the neck region of the intake valve causes flow resistance, which can lead to significant performance losses due to insufficient cylinder filling, especially in the upper load and speed range of the internal combustion engine. In addition, the carbon deposits in the neck region of the intake valve may prevent correct valve closing, which leads to compression losses and thus sporadic ignition failures. This in turn could irreversibly damage the catalytic converter. There is the potential for small particles to break away from the coating of carbon deposits in the neck region of the intake valve and get into the catalytic converter. These hot particles may then cause secondary reaction and corresponding local damage of the catalytic converter. For example, a hole may be burned in the structure of the catalytic converter."
"Globular deposits are found especially on the valve stem downstream from a partition plate in the intake port. Due to the dripping of high-boiling hydrocarbons from the partition plate towards the valve neck or valve stem, globular carbon deposits eventually form there by the sequence of events explained above. These deposits on the valve stem can result in flow deficits due to undesired swirling and turbulent flow around the globular carbon deposits. This may persistently interfere with the formation of stable tumble flow from cycle to cycle."
"A possible solution would be to keep these sources of deposits away, for example, from the intake valve, by completely eliminating exhaust gas recirculation and the introduction of blowby gases into the intake port. However with the combustion behavior of modern reciprocating internal combustion engines, at least external exhaust gas recirculation and the introduction of blowby gases into the intake port are absolutely necessary for reasons of emission control and fuel consumption, so that this approach is not possible. "
Directly from the technical staff of VAG is complete acknowledgment of the FSI intake valve deposit issue, and it's impacts, including: decreased performance, misfires, catalytic converter damage... etc.
"Gasoline engines with direct injection of the fuel into the combustion chamber, i.e., not into the intake port, suffer especially from the problem of the formation of carbon deposits on components. Carbon deposits form especially in the neck region of intake valves. A more exact analysis of how these carbon deposits form leads to the following result: Oil and fuel constituents first form a sticky coating on the components. These constituents are chiefly long-chain and branched-chain hydrocarbons, i.e., the low-volatility components of oil and fuel. Aromatic compounds adhere especially well. This sticky base coating serves as a base for the deposition of soot particles. This results in a porous surface, in which oil and fuel particles in turn become embedded. This process is a circular process, by which the coating thickness of the carbon deposits continuously increases. Especially in the area of the intake valves, the deposits originate from blowby gases and from internal and external exhaust gas recirculation, and in this process, the blowby gasses and the recirculated exhaust gas come into direct contact with the intake valve."
"Especially in the area of the neck of the intake valves, excessive carbon deposits have extremely negative effects for the following reasons: In the case of Otto direct injectors, the successful ignition of the stratified charge depends to a great extent on the correct development of the internal cylinder flow, which ensures reliable transport of the injected fuel to the spark plug to guarantee reliable ignition at the spark plug. However, a coating of carbon deposits in the neck region of the intake valve may interfere so strongly with the tumble flow that ignition failures may occur there as a result. Under certain circumstances, however, ignition failures can lead to irreversible damage of a catalytic converter installed in the exhaust gas tract for purifying the exhaust gas. Furthermore, the coating of carbon deposits in the neck region of the intake valve causes flow resistance, which can lead to significant performance losses due to insufficient cylinder filling, especially in the upper load and speed range of the internal combustion engine. In addition, the carbon deposits in the neck region of the intake valve may prevent correct valve closing, which leads to compression losses and thus sporadic ignition failures. This in turn could irreversibly damage the catalytic converter. There is the potential for small particles to break away from the coating of carbon deposits in the neck region of the intake valve and get into the catalytic converter. These hot particles may then cause secondary reaction and corresponding local damage of the catalytic converter. For example, a hole may be burned in the structure of the catalytic converter."
"Globular deposits are found especially on the valve stem downstream from a partition plate in the intake port. Due to the dripping of high-boiling hydrocarbons from the partition plate towards the valve neck or valve stem, globular carbon deposits eventually form there by the sequence of events explained above. These deposits on the valve stem can result in flow deficits due to undesired swirling and turbulent flow around the globular carbon deposits. This may persistently interfere with the formation of stable tumble flow from cycle to cycle."
"A possible solution would be to keep these sources of deposits away, for example, from the intake valve, by completely eliminating exhaust gas recirculation and the introduction of blowby gases into the intake port. However with the combustion behavior of modern reciprocating internal combustion engines, at least external exhaust gas recirculation and the introduction of blowby gases into the intake port are absolutely necessary for reasons of emission control and fuel consumption, so that this approach is not possible. "
Last edited by DirtyVegasTT; 12-15-2010 at 02:51 PM.
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12-16-2010, 07:31 AM
#29
AudiWorld Super User
Thread Starter
I honestly do not think that some cleaner in a vapor form is going to clean out a heavy deposit of the garbage that has caked itself onto metal through heat and over years of driving.
12-30-2010, 07:12 AM
#30
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It would be interesting to note what some contributing factors to this issue might be:
Do all of the Audi v10's have this issue? Would there be any reason that the S8 and R8 guys wouldn't be having this problem - if so, why not?
Does ethanol based fuel have any additional adverse effects? I know that in high efficiency marine motors it is almost mandatory anymore to use a fuel stabilizer like Stabil blue to avoid problems with the motors - could that be the case with our engines. Would we benefit from using pure gas, or stabilizing ethanol based fuels?
Are the guys that have had a tune done experiencing this issue more or less than non-tuned cars?
I know we are all kind of grasping for answers, but it would be nice to see some kind of patterns emerge and figure out if there is anything we can do differently to avoid decarbing our motors every 15k miles.
Do all of the Audi v10's have this issue? Would there be any reason that the S8 and R8 guys wouldn't be having this problem - if so, why not?
Does ethanol based fuel have any additional adverse effects? I know that in high efficiency marine motors it is almost mandatory anymore to use a fuel stabilizer like Stabil blue to avoid problems with the motors - could that be the case with our engines. Would we benefit from using pure gas, or stabilizing ethanol based fuels?
Are the guys that have had a tune done experiencing this issue more or less than non-tuned cars?
I know we are all kind of grasping for answers, but it would be nice to see some kind of patterns emerge and figure out if there is anything we can do differently to avoid decarbing our motors every 15k miles.