Carbon build up symptoms

[sakimano]

What are the noticeable symptoms of carbon build up?

Depends who you ask

If you ask b5 or b8 owners, carbon is an instant loss of 80 hp or more on the b7 the second you drive it twenty feet after carbon cleaning, and thus the car should never be coveted in any way.

If you ask b7 rs4 owners who run shitty track times or lose races, it is an absolute performance killer robbing them of 30-40 hp.

If you ask b7 owners who don't understand vacuum leaks and go to shops who don't understand ethical business, carbon is a killer that saps the rs4 of 80-100 hp.

If you ask b7 owners who are decent at driving and like to test their car where it counts...while accelerating on paved surfaces ...it's the cause of a loss of a small but not really detrimental amount of power, but you won't notice it unless you're incredibly perceptive.

[adsgreen]

The only time it will really have a noticeable difference is if the carbon fouls the intake manifold flaps. If this happens then the car will go into limp home mode with a large proportion of the air intake blocked off.

[GAZ-MAN]

Much are you roughly for the decoke and to get the flaps removed in the manifold you's reckon?

[OskiRs4]

Mine was £500 for a special offer mate, which I think they still do,
pre and post rolling road,
Plus they relocated the vacuum system pipe so its easy to get to if it was to fail, to be honest I think this had alot to do with my gains, as I really noticed it and my car was very under powered on the pre rolling road, but it seemed so much more lively once done and mine was very caked up,

[guffy]

Here's mine before/after...!!

That's not too bad, seen much worse, it probably looks like that again already

[toyneg]

Here are some pics of my carbon clean - sorry I don't have any after shots on me at the moment but this is 90k's worth of build up. And I can say the engine feels a lot smoother and alive since having it done. Power was up from 340ish to 430ish along with the stage 2 map (no vac leaks). I can confirm the car now feels like I always hoped it would, it's amazing how you don't realise how down on power you are unless you have a go in another healthy car to compare. Thanks to Silas and Noyjatat for that!

[sakimano]

What else was wrong?

[toyneg]

What else was wrong?

nothing apparently. certainly nothing i paid to have fixed

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What else was wrong?

I agree - I certainly wouldn't expect a power drop like that over the entire rev range. The ones I remember seeing seen have been "ok" (give or take some error) up to at least 4k rpm and then a tailing off then usually dropping like stone at 7k rpm. Wouldn't surprise me if there was an underlying vacuum leak (the one way valve under the manifold is a very common one - so common and cheap to replace that MRC do it as a matter of course).

[V8mark]

Hi,

Mine went in for the old carbon clean about a year ago, MRC said that it was 'fairly bad' in there but the car was still showing about 370 on the rollers from memory... I had it cleaned, de-flapped, and stage 2 mapped with a resulting 425 on the rollers. To be honest, I would say that the increase in performance (from the seat of the pants test - nothing scientific) is not really noticeable... however, the noticeable difference was how smooth the engine ran after and it pulled much smoother through the range.

My personal view is that the clean should be considered as part of the maintenance routine, maybe every 3yrs or so (just a personal thing) to keep the gunk out of the engine and allow it to operate and breathe as Audi intended, as with all mechanical stuff, it will last longer and perform to its best with good maintenance..... but dont expect a big increase in performance unless you are buggered to start with IMHO .....

[Cecilthesausage]

I could notice the difference at 5 and a half k....

[Audi Pardner]

I'm really in 2 minds about getting mine cleaned. It's just turned 50k, FSH etc and, as far as I know, has never been carbon cleaned. However, there are so many conflicting opinions on the forum (and elsewhere) that I don't know whether it's worth getting it done in conjunction with, say, a de-flap and map. As it's my first RS4 I have no way of knowing whether it's performing as it should do or is lacking. I guess the 5-8k test might give me an idea.

If I do go down the CC route, which specialist would forum members recommend, and which should I steer clear of? (please PM me to avoid naming & shaming if the latter ). Or is it a task that a competent indie like my tame mechanic (that I've used for years on other cars and I fully trust) could undertake? (I'm a mechanical <beep> ).

Any advice would be much appreciated guys.

[adsgreen]

If you are having work that involves the manifold off then really it's a no brainer and might as well.
If you think that there is a problem or issue then it won't hurt.
Otherwise don't fret about it.

[GAZ-MAN]

Am wanting to get mine booked in to get cleaned and deflapped and map tried phoning and leaving a message with unit20 today but got no reply, looking to get it booked in and done as I'm off over Christmas and new year for a fortnight which would be ideal

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Many on here (ok, some) have done it themselves and in principle if you are half way handy is not massive. You have to go through some hassle getting the manifold off but shouldn't be too much of a deal as long as you take your time.
Cleaning however is a pita. It's a manual scrub process. The part that is tricky is keeping the crap out of the cylinders.
Its a miserable time consuming job