Carbon buildup warranty extension
Hello guys. I am hearing that AoA has extended warranties on the 3.0 tfsi and 3.2 fsi engines. Any chance this will be extended to the d3 s8s? After reading all the carbon buildup threads I am concerned as to whether I have the issue as well. I am not the original owner so I don't have anything to compare to regarding power loss. The s8 has plenty of power but does feel like 450hp especially coming from modded b7 s4 4.2
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Originally Posted by ayrula
(Post 24519205)
Hello guys. I am hearing that AoA has extended warranties on the 3.0 tfsi and 3.2 fsi engines. Any chance this will be extended to the d3 s8s? After reading all the carbon buildup threads I am concerned as to whether I have the issue as well. I am not the original owner so I don't have anything to compare to regarding power loss. The s8 has plenty of power but does feel like 450hp especially coming from modded b7 s4 4.2
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Carbon
5 Attachment(s)
you can not see the carbon build up thru the spark plug hole.
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I agree with s4master1. Everything I've read also confirms that this is an fsi issue period. Low quality fuel just accelerates the problem. I doubt all the rs4 owners are using cheap gas, the problem goes beyond that.
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Sorry, I don't quite understand what "high rev & low load", "low rev & high load" or what combination.....exactly means. What would staying in 1st gear and driving it in 4k-5k RPM be??...high rev & high load?? I just need to grasp the meaning behind the rev/load combination. If I need to modify my driving habits to prevent future carbon issues, then please explain away. Thanks.
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Originally Posted by s4master1
(Post 24519220)
you can not see the carbon build up thru the spark plug hole.
We see the pictures, but there are also some questions; 1. What was the mileage? 2. How often was low quality fuel used? 3. Did the owner use Mobil 1 or other high quality synthetic oil, and how often was it changed? 4. Had the fine oil separator failed in some way, was it or the return feed to the crankcase blocked up by sludge, perhaps due to not following point 3? 5. Was the correct octane used, so that the variable valve timing never had to change to a point that there could be blow back of unburnt hydrocarbons into the intake manifold? |
Originally Posted by SoCalJ
(Post 24519243)
Sorry, I don't quite understand what "high rev & low load", "low rev & high load" or what combination.....exactly means. What would staying in 1st gear and driving it in 4k-5k RPM be??...high rev & high load?? I just need to grasp the meaning behind the rev/load combination. If I need to modify my driving habits to prevent future carbon issues, then please explain away. Thanks.
High load would be acceleration through the gears, where the engine is working hard at pulling the car along. |
Originally Posted by ayrula
(Post 24519235)
I agree with s4master1. Everything I've read also confirms that this is an fsi issue period. Low quality fuel just accelerates the problem. I doubt all the rs4 owners are using cheap gas, the problem goes beyond that.
I want to make it clear that I'm not defending Audi's DI design, even the most conservative valve timing and the best fine oil separator won't eliminate the problem over the lifespan of an engine. I've read of a yet to be implemented design that has a fuel injector in the intake manifold, designed to introduce just enough fuel to keep things clean. |
Originally Posted by ayrula
(Post 24519235)
I agree with s4master1. Everything I've read also confirms that this is an fsi issue period. Low quality fuel just accelerates the problem. I doubt all the rs4 owners are using cheap gas, the problem goes beyond that.
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Originally Posted by SoCalJ
(Post 24519243)
Sorry, I don't quite understand what "high rev & low load", "low rev & high load" or what combination.....exactly means.
High rev low load can be achieved in manual mode, driving in a lower gear with very little gas pedal. Unreasonable use of a Sport mode can give same results. Low rev high load would be lots of gas pedal while keeping a higher gear. Possible only in a manual mode and just to the certain point when automatic will kick in and shift into lower gear. Of course, all of this is way more relevant with manual transmission.
Originally Posted by EHLO
(Post 24519257)
Ok, your example is only the second I've seen of carbon buildup on a V10.
We see the pictures, but there are also some questions; 1. What was the mileage? 2. How often was low quality fuel used? 3. Did the owner use Mobil 1 or other high quality synthetic oil, and how often was it changed? 4. Had the fine oil separator failed in some way, was it or the return feed to the crankcase blocked up by sludge, perhaps due to not following point 3? 5. Was the correct octane used, so that the variable valve timing never had to change to a point that there could be blow back of unburnt hydrocarbons into the intake manifold? Millage is definitely relevant. Fuel quality is not with FSI engines. Oil quality or changing intervals won't make any significant difference either. This is not sludge. Any oil would create same deposits if it comes in contact with a hot surface. Oil separator is crucial, but not only factor. Oil can get there also leaking around valve studs. How much depends on a millage, age and driving habits. Abused engines, likely RS and S engines bought for the reason, work hotter and wear valve studs and seals faster. Most of oil is sucked into intake manifold under idling and engine braking. So, no unnecessary revving or Sport mode, no long idling for heating or air conditioning purposes and no forced downshifting is all we can do in order to prevent carbon buildup. Audi and other engineers have to take care of oil separators.
Originally Posted by EHLO
(Post 24519259)
The valve timing is different on the RS4, in that unburnt hydrocarbons can be blown back into the intake manifold under normal driving.
I've read of a yet to be implemented design that has a fuel injector in the intake manifold, designed to introduce just enough fuel to keep things clean. Injecting fuel to the intake valves keeps them cooler. Racing engines use fuel to cool combustion chamber and exhaust valves too. That's fire we can see from the exhaust under braking. |
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