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Discussion Starter · #1 ·
Here is a link to an Audi RS4 forum. Audi has been using Direct Injection since 2006 or earlier.

Check this out:

quattroworld.com Forums: Pictures and Dyno Plots

Now, do we know if Porsche boxer engines are experiencing the same issue? I know that the VW based Cayenne V6 engines are, but I am only interested in the flat sixes.

I know owners complain of soot, but is Carbon Buildup and loss of power over time a real concern with the Porsche engine?

Tomasz
 

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That ain't carbon, that's motor oil being ingested into the PCV system, and frying itself on the hot intake valves (and leaking into the combustion chamber). On port fuel injection engines the fuel washes much of it away, but with direct injection the intake path is dry, or at least it's supposed to be. ;) Oil in the PCV system is the bane of DFI cars, and some of the first generation designs did not include effective oil separators.
 

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I've posted on this before, but I suspect that using a heavier weight oil and running at higher average RPMs will probably keep valve coking at bay. I heard that Porsche had a fix for this problem due in the 2011 models. I guess very small chimney sweeps could be hired to clean out the intake ports (LOL).
 

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I am not taking any chances and want to keep the inside of the motor clean so I plan on using BG 44K. My dealer recommends it every 7-10 fill ups.
 

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I've posted on this before, but I suspect that using a heavier weight oil and running at higher average RPMs will probably keep valve coking at bay. I heard that Porsche had a fix for this problem due in the 2011 models. I guess very small chimney sweeps could be hired to clean out the intake ports (LOL).
or bring back road draft tubes
 

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I am not taking any chances and want to keep the inside of the motor clean so I plan on using BG 44K. My dealer recommends it every 7-10 fill ups.
You have an '09 Cayman S, so fuel additives or oil additives won't help if this problem is occurring. I haven't seen an reports yet of DFI Caymans or Boxsters having a problem, so perhaps Porsche properly designed the oil separator this time.
 

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You have an '09 Cayman S, so fuel additives or oil additives won't help if this problem is occurring. I haven't seen an reports yet of DFI Caymans or Boxsters having a problem, so perhaps Porsche properly designed the oil separator this time.
I haven't heard any issues yet either and hope they designed it properly considering that DFI issues are not new so they must have taken all the lessons learned and designed it properly.

When I asked my dealer about carbon DFI issues and what one can do to protect against it, they told me to use BG44K and they recommend to clients to use it every 7-10 fill ups. It might not be as effective than using it on EFI cars but if it does help a bit then I use it. I am about to buy some as I am almost on fill-up number 8!

The best trick to prevent this is to drive it like a Porsche should be driven! Higher revs will prevent some build-up of deposits and will keep the car running in peak performance.

I read here a while ago that some people would wipe the soot of the tail pipes and after a weekend of track they would still be clean!
 

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Discussion Starter · #8 ·
I am not taking any chances and want to keep the inside of the motor clean so I plan on using BG 44K. My dealer recommends it every 7-10 fill ups.
BG 44K or any gas additives will not make it into the valves - they do not get sprayed with fuel. Only way to clean valves without taking the engine apart is water or meth injection - after market, and of dubious though potential results.
 

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Discussion Starter · #9 · (Edited)
You have an '09 Cayman S, so fuel additives or oil additives won't help if this problem is occurring. I haven't seen an reports yet of DFI Caymans or Boxsters having a problem, so perhaps Porsche properly designed the oil separator this time.
I hope so. Most Audis do not see this problem till 30,000 miles. I am afraid that we just do not know yet.

Our flat engines have been prone to oil in the intake... if that continued with the DFI design then we will experience big issues with this as well.

Hmm... well, I am not buying a new car for 1+ years. By then we should know what is up.

BTW: "There was an interesting thread on RS246 where a guy put some gauze in his PCV system to see how much oil was blowing by. After 2 weeks the gauze was completely clean. Zero PCV blowby which would make a catch can a waste, and throws that theory out."

Tomasz
 

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Discussion Starter · #10 ·
The best trick to prevent this is to drive it like a Porsche should be driven! Higher revs will prevent some build-up of deposits and will keep the car running in peak performance.

I read here a while ago that some people would wipe the soot of the tail pipes and after a weekend of track they would still be clean!
I do not think that intake valve build up and soot are directly related. RS4s redline at 8,200 RPM and they make such a gorgeous sound there that MANY owners take them to the limit to hear it. I know that high RPMs, and driving the car hard on the track has not helped.

If this is oil, as blueone states, than maybe avoiding short trips and starts would help... but that is not something that many can do.

BG K44 does not help at all on the intake. It NEVER gets there, it can not help. Think about it. Unless you pour it all over the air filter.

Dealers are suggesting it, because they can not solve the real issue without taking then engine apart.

Gosh, I hope Porsche did this one right. As I want my next car to be a DFI.

But this does not look good:

"I'm going to try doing my own cleaning with some GM Top Engine cleaner. The local BMW dealer is using it by the case to combat carbon buildup on the new BMWs. Supposedly it works better than seafoam or even BG. I have two cans and may try doing it this weekend."

"It comes in either a bottle or aerosol cans. I got the aerosol cans so I can spray it into the intake while the car is running and have it work through that way to clean the carbon. It'll be interesting to see how effective it is."
 

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When I asked my dealer about carbon DFI issues and what one can do to protect against it, they told me to use BG44K and they recommend to clients to use it every 7-10 fill ups. It might not be as effective than using it on EFI cars but if it does help a bit then I use it. I am about to buy some as I am almost on fill-up number 8!

The best trick to prevent this is to drive it like a Porsche should be driven! Higher revs will prevent some build-up of deposits and will keep the car running in peak performance.
Yeah, we heard you about the BG44K. Did you hear us that in a DFI car the fuel, and therefore the BG44K will never touch the backside of the valves, so there will be no cleaning effect? Does the dealer know that Porsche specifically recommends against any fuel additives?

As for driving hard keeping oil out of the intake, I'm sorry, but almost certainly the opposite is true. It is high engine vacuum that causes the PCV system to suck oil into the intake. Getting off the throttle at high revs, as you might in hard driving, drives vacuum way up.

The street wisdom about hard driving keeping an engine clean from carbon, which is unrelated to the photos in this thread, is mostly from long ago, before high-voltage electronic ignition systems, fuel injection, and modern detergent gasoline. I have to admit, though, I like the notion that it might keep the engine healthy, so I wind it up here and there. :)
 

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If this is oil, as blueone states, than maybe avoiding short trips and starts would help... but that is not something that many can do.
If you look at the first picture, that valve build-up looks gooey and shiny, and it is so thick it seems unlikely that's carbon. Carbon build-up looks like powder-coat before you bake it, or like a black ceramic coating on the tops of the pistons. That's why I think we're looking at oil build-up.
 

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Yeah, we heard you about the BG44K. Did you hear us that in a DFI car the fuel, and therefore the BG44K will never touch the backside of the valves, so there will be no cleaning effect? Does the dealer know that Porsche specifically recommends against any fuel additives?

As for driving hard keeping oil out of the intake, I'm sorry, but almost certainly the opposite is true. It is high engine vacuum that causes the PCV system to suck oil into the intake. Getting off the throttle at high revs, as you might in hard driving, drives vacuum way up.

The street wisdom about hard driving keeping an engine clean from carbon, which is unrelated to the photos in this thread, is mostly from long ago, before high-voltage electronic ignition systems, fuel injection, and modern detergent gasoline. I have to admit, though, I like the notion that it might keep the engine healthy, so I wind it up here and there. :)
Yes, the dealer stated that although Porsche doesn't recommend fuel additives they still recommend BG44K & sell it....its the only thing they recommend. I am still debating if I will use it or not.
 

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I hope so. Most Audis do not see this problem till 30,000 miles. I am afraid that we just do not know yet.
Do you mind telling me where you pulled this from? I'm active on the Audi forums and own a 2.0T DFI A3. While there have been a few RS4's with the buildup problem, it is far from an epidemic. I have an A3 2.0T DFI that just crossed 50K miles and I've had zero issues. Seems to be the norm amongst owners.

I think the DFI "carbon buildup issue" blown HUGELY out of proportion. While it COULD be a problem for some cars, the actual reported problems seem minor by comparison. Time will tell. I've got 50K miles of warranty on my CS. If it becomes an issue, Porsche will fix it.... just like IMS and RMS failures ;)
 

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Do you mind telling me where you pulled this from? I'm active on the Audi forums and own a 2.0T DFI A3. While there have been a few RS4's with the buildup problem, it is far from an epidemic. I have an A3 2.0T DFI that just crossed 50K miles and I've had zero issues. Seems to be the norm amongst owners.

I think the DFI "carbon buildup issue" blown HUGELY out of proportion. While it COULD be a problem for some cars, the actual reported problems seem minor by comparison. Time will tell. I've got 50K miles of warranty on my CS. If it becomes an issue, Porsche will fix it.... just like IMS and RMS failures ;)
Agree. I've been looking at DI motors on the net the last few days, as I'm going to replace my daily driver, but it's not like you go on the Porsche/Audi/BMW/Caddy/VW, etc forums and find that there are tons of threads on the subject. No doubt you can find the issue on most DI related forums but it's not what I would call an epidemic.
 

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Discussion Starter · #18 ·
Do you mind telling me where you pulled this from? I'm active on the Audi forums and own a 2.0T DFI A3. While there have been a few RS4's with the buildup problem, it is far from an epidemic. I have an A3 2.0T DFI that just crossed 50K miles and I've had zero issues. Seems to be the norm amongst owners.

I think the DFI "carbon buildup issue" blown HUGELY out of proportion. While it COULD be a problem for some cars, the actual reported problems seem minor by comparison. Time will tell. I've got 50K miles of warranty on my CS. If it becomes an issue, Porsche will fix it.... just like IMS and RMS failures ;)
Quattroworld.com, RS4 forum. The same forum I linked in my first post.
 

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Discussion Starter · #19 ·
I think the DFI "carbon buildup issue" blown HUGELY out of proportion. While it COULD be a problem for some cars, the actual reported problems seem minor by comparison. Time will tell. I've got 50K miles of warranty on my CS. If it becomes an issue, Porsche will fix it.... just like IMS and RMS failures ;)
I also thought that DFI issue was hugely blown out of proportion. The odd thing is that many people who always thought that, are now finding gunk in their engines and switching sides. 1 year ago, people made fun of anyone that claimed this an issue. Today the same people are claiming this as an issue. NA engines seem more affected, I do not know why.

But, I really only care at this point about the DFI Porsche flat sixes... anyone?
 

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My DFI is very new and I'm sure those intake valves are clean and shiny. I'm going to drive and enjoy,and if those valves are coated with oil in 50000 km I'll cross that bridge when I get there. You really can't enjoy a ski run if you worry about falling all the way down. I believe the same principle applies here. If you want to worry about everything go ahead, but it will detract from the pleasure of ownership. For now,let's just say this could be an issue for future concern.:cheers:
 
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