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I'm after a bit of advice please. I have spoken to a company called ADS in Preston about having my new Scorpion non-res valved cat back fitted and then a re-map on my 2006 RS4 B7 Avant and he firstly asked if my engine had been de-coked. My car has just reached 81k miles and has full Audi service history but I cant see that this has been done. He suggested that having this done first could give me 50 or 60 horses back?? I am extremely sceptical about this. Could you knowledgeable lot please advise me if I'm being sold a duff one or not?

Thanks in advance.

By all means spend all that money and have it done, it will give you some more power and generally make it drive better but it will soon be coked up again and you'll be back to where you are now.
If I was having a remap done I'd want it done with the engine in the state that it will spend most of its time and that is coked up. I'd only have it mapped with a clean engine if you intend on having it cleaned every year.

Get your manifold ported and polished and deflapped it will prolong the carbon build up after a clean.

If it's never been cleaned, yeah it could make a considerable difference to power. As Mike says though, It won't last! Thanks Audi

I got 44hp back after a clean (and mine had already been cleaned a year earlier).

If you're feeling bored, have a read through this. Started off testing hydrogen carbon cleaning, ended up getting the mani cleaned the old fashioned way by MRC:

viewtopic.php?f=35&t=117463&start=105

Mine has 60,000 miles and was dyno'd by MRC at 376PS (15% down) 18 months ago. Since then I've run on Tesco Momentum most of the time (or Shell V-Power occasionally) and poured in Audi's additive G-001-770-A2 at every other fill. Now, believe it or not, keeping the revs up in all gears seems to be clearing the carbon and it is running smoother now than it ever has done. This may be all in the mind and I'm sure many of you will think this (and of course the only surefire measurement would be on the dyno again) but I think it works! Momentum plus magic fluid plus high revs = one happy bunny!

ChrisR wrote:He suggested that having this done first could give me 50 or 60 horses back??

MRC reckon a carbon clean is worth no more than 30bhp, and a vacuum leak as much as 60bhp.

I paid for a CC and vacuum leak check. No leaks but a shed load of carbon removed, would I pay for it again? No, not unless there was a vacuum leak. A CC costs £7-800, is 30bhp worth that?

ChrisW wrote:A CC costs £7-800, is 30bhp worth that?

Especially as the carbon build up will usually re-appear after 5000 miles or so.

Better to just do a regular "Italian Tune" or "drive it like you stole it"

PetrolDave wrote:

ChrisW wrote:A CC costs £7-800, is 30bhp worth that?

Especially as the carbon build up will usually re-appear after 5000 miles or so.

Better to just do a regular "Italian Tune" or "drive it like you stole it"

Hear hear!

I've just done as Jay has suggested.

Removed the flaps and ported and polished the intake manifold. It's currently still in bits (going back together this weekend) but I quite enjoyed doing the work myself and I will probably make it a yearly thing. As other have also suggested. The good old itailian tune is the best way to keep it at bay if you have it done and as mine is our 3rd car then when it gets used its always in anger

right guys ive been reading alot about the carbon clean etc and it coming back. what is needed is a full strip and carbon clean then a seperate oil catch tank system to be set up this is why its happening. this is going to be the first thing i do on mine including some nice polishing work on the inlet.

knight7660 wrote:right guys ive been reading alot about the carbon clean etc and it coming back. what is needed is a full strip and carbon clean then a seperate oil catch tank system to be set up this is why its happening.

That's a negative. The deposits are from exhaust gases reaching the intake due to normal valve overlap. The catch can theory was tried and proved fairly useless years ago. If only we had been lucky enough to have a solution that easy everyone would have it by now.

JCviggen wrote:

knight7660 wrote:right guys ive been reading alot about the carbon clean etc and it coming back. what is needed is a full strip and carbon clean then a seperate oil catch tank system to be set up this is why its happening.

That's a negative. The deposits are from exhaust gases reaching the intake due to normal valve overlap. The catch can theory was tried and proved fairly useless years ago. If only we had been lucky enough to have a solution that easy everyone would have it by now.

This^^^^^

JCviggen wrote:That's a negative. The deposits are from exhaust gases reaching the intake due to normal valve overlap. The catch can theory was tried and proved fairly useless years ago. If only we had been lucky enough to have a solution that easy everyone would have it by now.

+1

Many members on here tried catch tanks several years ago (it's all documented in this forum in some of the old threads )and the difference it made to how many miles it was before carbon reappeared was - absolutely zero, zilch, nada, nothing.

Thanks for all the replies guys. Very interesting. With regards to 'port and polish' the inlet manifold, what exactly does this entail? Can it be done at home by me, fairly competent with the spanners .