Close

    • Just how much does direct injection carbon buildup hurt? B7 RS4 gains 42 wheel horsepower after 034Motorsport carbon cleaning

      One of the downsides of direct injected motors is carbon buildup. Over time carbon builds up on the intake valves cluttering them up and having a detrimental effect on an engine's performance. Oil and fuel essentially gets on there and this creates a circular problem of more and more oil and fuel clinging to the deposits and the thickness of the deposits around the valves increases. Just how bad can this be? Just take look at how much material was removed from a B7 RS4.


      That is quite a bit of material, isn't it? There is no way anyone could expect an engine to function as it should with it being gunked up with that much carbon. This car had 69800 miles on it and did not have any aggressive modifications only a rear section exhaust and filter.

      As for the effect on performance, the baseline on a Mustang all wheel drive dyno before the cleaning showed 287 horsepower to the wheels and 240 pound-feet of torque to the wheels. After the cleaning these figures change to 329 horsepower and 266 pound-feet of torque. A night and day difference.

      There are measures that can be taken to minimize carbon buildup such as oil catch cans and methanol injection but this will be an issue no matter what and one owners of direct injected engines should monitor. A good cleaning can make the car feel like new especially if one gets the impression it has become sluggish over time.

      Valves before the cleaning:


      Valves after the cleaning:


      Dyno:


      This article was originally published in forum thread: Just how much does direct injection carbon buildup hurt? B7 RS4 gains 42 wheel horsepower after 034Motorsport carbon cleaning started by Sticky View original post
      Comments 25 Comments
      1. rdeterman's Avatar
        rdeterman -
        That's unbelievable.. Hard to imagine all of that coming off one motor.
      1. AlexQuattro's Avatar
        AlexQuattro -
        Click here to enlarge Originally Posted by rdeterman Click here to enlarge
        That's unbelievable.. Hard to imagine all of that coming off one motor.
        There's no way all that carbon is from one motor. Just look at the carbon in the intake port picture, multiply that by 8. It's only a fraction of what is in the tray. There's no way....
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by AlexQuattro Click here to enlarge
        There's no way all that carbon is from one motor. Just look at the carbon in the intake port picture, multiply that by 8. It's only a fraction of what is in the tray. There's no way....
        You're saying they exaggerated it?
      1. AlexQuattro's Avatar
        AlexQuattro -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        You're saying they exaggerated it?
        Not at all. Common sense is telling me that what is in the tray is too much carbon for one motor. Do they claim it is from one motor? Is there a link with more pictures?
      1. leveraged sellout's Avatar
        leveraged sellout -
        I believe it. I've spent some time on the big carbon buildup threads for RS4s. Crazy stuff. These are amazing engines but the carbon buildup is almost beyond belief. If I had one I'd have meth and a catch can and I'd drive the piss out of it every possible chance in order to minimize it...this must be an expensive process.
      1. sammy_0559's Avatar
        sammy_0559 -
        hmm i need to start working on audis. lol
      1. AlexQuattro's Avatar
        AlexQuattro -
        If all that carbon was put inside the intake ports, the size of the ports would be considerably reduced and would hardly let any air through. Maybe the carbon is accumulating somewhere else too? That is a $#@!load of carbon compared to what is on the intake port picture.

        Perhaps I should have said it this way: there is no way all that carbon is coming from the intake ports of one motor. I'd like to know where the carbon is also building up. Anyways, time for this kid to go to bed.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by AlexQuattro Click here to enlarge
        Not at all. Common sense is telling me that what is in the tray is too much carbon for one motor. Do they claim it is from one motor? Is there a link with more pictures?
        The implication is this is from one motor.
      1. George Smooth's Avatar
        George Smooth -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        The implication is this from one motor.
        can an I post some pics of carbon build up on a Rs4 but they have my company logo, I have cleaned over 30 of them.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by George Smooth Click here to enlarge
        can an I post some pics of carbon build up on a Rs4 but they have my company logo, I have cleaned over 30 of them.
        You've more than earned the right to do so.
      1. George Smooth's Avatar
        George Smooth -
        Here are some pictures of RS4' at various mileage.

        Attachment 36262

        This will give you a idea of quantity of Carbon, I would say a heaped table spoon per port.
        Attachment 36263

        Attachment 36264

        and here is a really high mileage car. The port divider has a match stick on to give you a idea. I am surprised this car even idled.
        Attachment 36265

        We are seeing slightly less in power gains than 034 showed but the gains are major never the less. It also looks like our cleans are better in quality Click here to enlarge
      1. Sticky's Avatar
        Sticky -
        Is the amount of carbon in the tray from one motor?
      1. George Smooth's Avatar
        George Smooth -
        Click here to enlarge Originally Posted by Sticky Click here to enlarge
        Is the amount of carbon in the tray from one motor?
        I cannot tell how big the tray is but I would say 99% that the carbon is not from the motor of which the valves are pictured. In my opinion and I could be wrong there isnt enough carbon on the valves pictured to allow scooping of the carbon. Also when its so little carbon the port dividers which gather a lot of carbon have a very thin surface.
      1. Sticky's Avatar
        Sticky -
        Click here to enlarge Originally Posted by George Smooth Click here to enlarge
        I cannot tell how big the tray is but I would say 99% that the carbon is not from the motor of which the valves are pictured. In my opinion and I could be wrong there isnt enough carbon on the valves pictured to allow scooping of the carbon. Also when its so little carbon the port dividers which gather a lot of carbon have a very thin surface.
        Thank you.
      1. AlexQuattro's Avatar
        AlexQuattro -
        Click here to enlarge Originally Posted by George Smooth Click here to enlarge
        Here are some pictures of RS4' at various mileage.

        This will give you a idea of quantity of Carbon, I would say a heaped table spoon per port.

        and here is a really high mileage car. The port divider has a match stick on to give you a idea. I am surprised this car even idled.

        We are seeing slightly less in power gains than 034 showed but the gains are major never the less. It also looks like our cleans are better in quality Click here to enlarge
        Awesome post! Excuse my language but holy $#@!ing $#@! that is disgusting. And I agree you're cleans are better as they leave no residue at all.
      1. 0-60Motorsports's Avatar
        0-60Motorsports -
        Click here to enlarge Originally Posted by George Smooth Click here to enlarge
        Here are some pictures of RS4' at various mileage.

        Attachment 36262

        This will give you a idea of quantity of Carbon, I would say a heaped table spoon per port.
        Attachment 36263

        Attachment 36264

        and here is a really high mileage car. The port divider has a match stick on to give you a idea. I am surprised this car even idled.
        Attachment 36265

        We are seeing slightly less in power gains than 034 showed but the gains are major never the less. It also looks like our cleans are better in quality Click here to enlarge
        WOW. That is scary. Good Job on the cleaning mate.
      1. fastgti69's Avatar
        fastgti69 -
        I really need to get on this before the single or something. @alpinedevil335 This looks like a nightmare.
      1. leo985i's Avatar
        leo985i -
        The N54 is an engine that runs very very dirty too. My last N54 had to get cleaned at 50k cus it couldn't even do a pull at 13psi without coughing like a bad smoker leading to SES lights all the time. My 2nd N54 is up for a clean up, the car is now sitting at 61k miles, I can't even imagine how bad the valves look already, but this maintenance is not cheap, which sucks even more.
      1. George Smooth's Avatar
        George Smooth -
        Click here to enlarge Originally Posted by leo985i Click here to enlarge
        The N54 is an engine that runs very very dirty too. My last N54 had to get cleaned at 50k cus it couldn't even do a pull at 13psi without coughing like a bad smoker leading to SES lights all the time. My 2nd N54 is up for a clean up, the car is now sitting at 61k miles, I can't even imagine how bad the valves look already, but this maintenance is not cheap, which sucks even more.
        Labour is cheap in South Africa, we do N54/55's for $250 inclusive of gaskets.
      1. Stevenh's Avatar
        Stevenh -
        How many hours of labor on the N54/55? How about the Audi motors?