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Preventing carbon build up [2.0 TFSI]

Discussion in 'A3/S3/Sportback (8P Chassis)' started by s3_trev, May 7, 2014.

  1. s3_trev
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    s3_trev 3 door or no door!

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    [May 7, 2014]
    Hey peeps, I wanted to ask what the general opinion is with regards to preventing carbon build up on the insides of the 2.0 TFSI engines? I am aware this is an issue with these engines and obviously I would like to counter act this as much as possible. Prevention is better than cure and all that. So far I have found the following to be possible counters:

    1. Regular oil changes with good quality oil
    2. Fuel treatments every few fills
    3. High octane fuel
    4. Oil catch can system
    Would you all agree with the above? I would appreciate any input anyone has on this subject.

    Thanks.
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  2. s3_trev
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    s3_trev 3 door or no door!

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    [May 8, 2014]
    Wow thought there would be loads of opinions on this.
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  3. luckbox
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    luckbox New Member

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    [May 8, 2014]
    I'm getting my intake valves cleaned next week. Car has already 86k miles so thought it's time to do it. Also looking for tips on preveting the carbon build up in the future.
    #3
  4. S3_Mat
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    S3_Mat Active Member

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    [May 8, 2014]
    I do not know alot on the topic, other than the fact that a catch can is able to help but the difference isnt massive and there is still buildup on the intakes. It's the nature of the beast unfortunately once the carbon is baked on its very difficult to remove and there is no proven way to stop the gasses getting into the intake without a full pcv delete and venting crankcase pressure a different way. Which is not cheap i believe.
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  5. s3_trev
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    s3_trev 3 door or no door!

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    [May 8, 2014]
    Where abouts are you getting that done? Do you know what the procedure involves? Cost? Thanks.
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  6. S3Alex
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    S3Alex Rarely neutral

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    [May 8, 2014]
    I may know a bit more than some...LOL.

    My car has been decoked twice.

    First at 30 000 miles and again at 65 000 miles,both times when the engine was in bits,allowing easy access to the intake ports and valves.

    This is what it looks like before.....


    http://i1251.photobucket.com/albums/hh544/s3alex/DSC044241024x768_zps62fe53c2.jpg


    http://i1251.photobucket.com/albums/hh544/s3alex/DSC044221024x768_zps686b7b7d.jpg


    And after.....

    http://i1251.photobucket.com/albums/hh544/s3alex/DSC044251024x768_zpsf4a81065.jpg

    On the TFSi,it won't make any difference what type of fuel you use(aside from diesel of course...LOL) or whether or not you use fuel additives,as this is a direct injection engine,and fuel does not enter the inlet tract above the valves.

    A catch can will get some of the ****,but not all,because VAG in their efforts to cut emissions,added another breather from the cam cover,exiting into the inlet above the turbo,so whatever happens,you WILL get some oil vapour meeting hot valve stems,and this is the result.

    The only surefire way to prevent it is a full PCV delete,which is a pain,as you need a cam breather system,and catch can,and you need to ensure that neither cam nor crankcase pressures rise to the point where oil is blown past seals.


    Mine BTW,has had a catch can from 12 000 miles on,and the **** on the valves accumulates despite that,as I've explained.

    I'm going to have a new cam cover and breather fitted shortly,and have the extra injector setup running soon as well.....the latter is for more power,but this is a side benefit of an 8 injector setup,but not something I would recommend for anyone not running a big turbo system and needing a LOT of extra fuelling.

    For all of us with TFSi engines,the best solution is a regular decoke,and AMDTuning can do this easily and quickly,as was done to mine.


    It's a relatively straightforward process,not horribly expensive,as very easy if you have the right equipment.....which they have!
    Last edited: May 8, 2014
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  7. s3_trev
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    s3_trev 3 door or no door!

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    [May 8, 2014]
    Thanks alex. Does a "de-coking" involve taking the head off yeah? I would imagine it does.
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  8. S3_Mat
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    S3_Mat Active Member

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    [May 8, 2014]
    Just the inlet manifold trev, there is a process where crushed walnut shell is blasted into the valves to dislodge the carbon. Walnut is used as its hard enough to remove the bits without doing damage to the head or valves. Quite alot of walnut is needed sometimes up to 12Litres but the before and after pictures show its very effective.

    If the head is off for other work an acid bath can be used.

    The exhaust valves do not suffer as much as the inlet.
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  9. S3Alex
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    S3Alex Rarely neutral

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    [May 8, 2014]
    No.

    It does involve the inlet manifold coming off though,and that's when mine was off recently.

    The first view looked like this......

    http://i1251.photobucket.com/albums/hh544/s3alex/56d11e4494dfc2f71bf43f20fff47f08_zps14713558.jpg


    http://i1251.photobucket.com/albums/hh544/s3alex/b6365f4f89c14c4c87d5cbe881075509_zps91abf3ab.jpg


    And the after pics you've already seen,so that we could fit this beauty.


    http://i1251.photobucket.com/albums...F-DA7E-4211-8606-E48CA2D12CFF_zpsvyzxyz9v.jpg
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  10. S3Alex
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    S3Alex Rarely neutral

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    [May 8, 2014]
    The exhaust side as you say,is basically unaffected by this build-up.

    The work AMD did on mine was superb,and basically looks as new after being cleaned,and the difference in performance certainly was very noticeable.
    Obviously,it's going to be less of a gain on a stock engine,but very clear with a higher powered engine.
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  11. fangio
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    fangio Well-Known Member

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    [May 8, 2014]
    How the hell does an inlet side of a petrol engine coke up?
    It must be connected directly to the exhaust plpe!:(






























    i
    #11
  12. batch
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    batch Active Member

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    [May 8, 2014]
    Just seen those pics Alex... Jeez, your inlet valves reminded me of the exhaust side of my old Stage 3 1700 Crossflow head! Bloody hell!
    Wonder when I should get mine done...
    #12
  13. Granta
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    Granta Active Member

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    [May 8, 2014]
    I believe I have a carbon build up issue, slightly lumpy on cold start up and seems to clear itself and an occasional misfire on idle, nothing under load and mines on 51k. Diagnostic machine says misfire cylinder 4 swapped plugs and coils and still on number 4 so could be an injector or head/valves
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  14. Newtoys3
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    Newtoys3 Member

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    [May 8, 2014]
    Had mine done last week at surreyside autohaus in guildford for the 2nd time, they say they do it as routing maintainance every 30k, again as above manifold comes off everytime
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  15. S3Alex
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    S3Alex Rarely neutral

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    [May 8, 2014]
    Very easily.

    When you route engine breathers into the intake,a lot of oil vapour is sent to the intake,and with an "old school" injection system above the valves,all the **** gets washed off.

    With a direct injection engine,this can't happen as the fuel is injected directly into the cylinders,and bypasses the valve stems etc,hence the coke build-up.
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  16. S3Alex
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    S3Alex Rarely neutral

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    [May 8, 2014]
    I've had a catch can on mine from 12 000 miles,and the decokes were done at 30 000 and 65 000 miles,so if your's fits into that anywhere,it may be worthwhile.


    Possibly.

    The injectors are pretty much bulletproof,but as you can see,the **** build-up is impressive,and because it's slow and gradual,we mostly don't notice the drop-off in performance until its pretty clear.
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  17. davc
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    davc Foursprung Duck Technik

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    [May 8, 2014]
    Slightly off topic but I read online that the new tfsi engines run both port and direct injection which if true sounds fantastic.
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  18. S3Alex
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    S3Alex Rarely neutral

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    [May 8, 2014]
    Where did you read that?

    That means running at least one if not 4 extra injectors.
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  19. davc
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    davc Foursprung Duck Technik

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    [May 8, 2014]
    Can't remember but I'll try and find the web page.
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  20. S3Alex
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    S3Alex Rarely neutral

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    [May 8, 2014]
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  21. fangio
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    fangio Well-Known Member

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    [May 8, 2014]
    I'm bloody glad mine's a diesel! :haha:
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  22. luckbox
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    luckbox New Member

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    [May 8, 2014]
    This is what is going to be done to my car. It will be done by APR here in Finland. Cost is 500 euros so around 400 pounds. I haven't had any symptoms like missfires or powerloss but hoping this clean up could bring back a few extra horsepower... Have people experienced a smoother engine and slight power gains after doing this?
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  23. S3Alex
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    S3Alex Rarely neutral

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    [May 8, 2014]
    Yes to smoother delivery and more power.

    Mine was running around 490-500bhp on 2 bar prior to the new manifold and having the intake cleaned out.

    Now,on 1.9bar,it's smoother and faster,and has a much better top end.

    You'll get less of a gain on a Stg2+ engine,but I can only see benefits from doing this.
    #23
  24. Newtoys3
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    Newtoys3 Member

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    [May 8, 2014]
    Wow £400 ! Finland must be a expensive place, half that price over here in uk
    #24
  25. desertstorm
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    desertstorm Well-Known Member

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    [May 8, 2014]
    I would have thought some kind of water injection system would keep the intake side clean. It's a side effect of the water injection and also would help on more modded cars.

    Karl.
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  26. luckbox
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    luckbox New Member

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    [May 8, 2014]
    Yeah definetely more expensive than UK; (btw a new S3 here costs without any optional extras 56.5k€ (46k£) which includes 15k€ tax to the government... :noway:

    Anyways they told me this clean up is a 3 hour job, wonder if I am getting ripped off?? Anyone know if this is right?
    Last edited: May 8, 2014
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  27. S3Alex
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    S3Alex Rarely neutral

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    [May 8, 2014]
    You and I might both have thought that.

    I have WMI on mine,using the biggest injector on the AEM system,and mapped for 2bar on a big turbo....it's injected pre-throttle body,and it has no obvious effect on build-up.

    It's possible that if you used port injection you might get an effect,but that means a whole lot more work on the WMI system,and most of us use pre-TB injection for cooling,plus you aren't actually pouring in huge amounts either.
    #27
  28. davc
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    davc Foursprung Duck Technik

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    [May 8, 2014]
    Here's the page I was referring to:

    Audi Gives Us the Skinny On Its Third-Gen EA888 Turbo Four and the SQ5’s Twin-Turbo Diesel V6 | Car and Driver Blog
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  29. S3Alex
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    S3Alex Rarely neutral

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    [May 8, 2014]
    #29
  30. davc
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    davc Foursprung Duck Technik

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    [May 8, 2014]
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  31. s3_trev
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    s3_trev 3 door or no door!

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    [May 8, 2014]
    Except NI. Going to have to find a local garage that does this. Car is going into a local VAG specialist on the 23rd, so will ask them if its something they do.
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  32. S3Alex
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    S3Alex Rarely neutral

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    [May 8, 2014]
    Last edited: May 8, 2014
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  33. davc
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    davc Foursprung Duck Technik

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    [May 8, 2014]
    It's maybe a long shot but you could try a BMW garage as I've heard a lot of them now do the walnut blasting.
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  34. Granta
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    Granta Active Member

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    [May 8, 2014]
    has anyone had the walnut shell blasting? im keen to try it but the thought of some shell breaking up and going into the cumbustion chamber worries me.
    #34
  35. S3Alex
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    S3Alex Rarely neutral

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    [May 8, 2014]
    I wouldn't let that worry you.
    #35
  36. Granta
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    Granta Active Member

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    [May 8, 2014]
    why do you think that? unless you take the cams on some valves should be open..
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  37. S3_Mat
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    S3_Mat Active Member

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    [May 8, 2014]
    Not sure if i can post to another forum on here. But if you search "walnut blasting bmw" in google there is a thread which will explain how its done.
    #37
  38. S3_Mat
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    S3_Mat Active Member

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    [May 8, 2014]
    They used the starter to get the next valve to close or using the crankbolt to turn the engine..
    #38
  39. Granta
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    Granta Active Member

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    [May 8, 2014]
    ha ha dull moment from me, of course! turn the engine over till the valves are closed!!
    #39
  40. Sevv
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    Sevv Pushing the limits..

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    [May 9, 2014]
    you best bet is buying a non TFSI TDI engine as the injectors spray directly on the piston make it efficient when new and worse then the 1.8T after 10k miles.. the only way i think to minimize it is buy getting a manifold like alex priming the injector to soak the valves every so often which would keep it clean a catch can will help but not cure it as in Alex's case.. the old 1.8T didn't have this problem as the injectors sprayed directly onto the valves top down approach unlike the TFSI etc..

    what also would be interesting is alongside the fuel rail on Alex's manifold if he got port injection; wonder how that would work on the carbon build although methanol is being sprayed in miniscule portions
    Last edited: May 9, 2014
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