Jake-AudiUSAParts

Audi's fuel additive works great for frequent "maintenance" use, every other fill-up is about how often I would recommend using it. Click HERE to be taken directly to it's page on our site.

SloopJohnB@mac.com

I agree…it's one of the few things keeping me away from a DI engine. I've looked at and walked away from S6 and S8 V10 cars because of the maintenance cost associated with decarboning the intake ports. Same with the R8 V8 and V10. It's not an issue under warranty, but after 4/50 it's your wallet! The dealer takes no prisoners and the manifold has to come off to even start. My dealer talks a good story about walnut blasting but he doesn't have one (yet, according to the techs).

jakematic

Aren't there storage concerns with G17 Jake ?
I want to get some, but it seems like prosciutto to me - not something you want to keep in the trunk....

GnatGoSplat

Wife is dead set on getting an A8L, but this issue and the fact that some people in this thread are worried enough to avoid FSI engines altogether has me worried as well. Isn't it the same engine used in the RS4? Is it possible that A8L engines are getting gunked up just as frequently, but the typical A8L driver just wouldn't notice 10% less power over time compared to a typical performance-oriented RS4 driver?

I've seen threads where people insist that venting PCV to atmosphere (VTA) fixes this problem. However, I saw one link where someone insists this doesn't work and that it's a design flaw for which regular cleaning is the only solution. Although that person linked to other threads as proof which I read in their entirety and didn't see anyone saying VTA doesn't work, so I'm a bit confused why he said that. I looked at photos of the cyclonic PCV cleaning apparatus on the 4.2L FSI engine and it looks fairly complex. Is there even available fittings to convert it to VTA? How about VTA utilizing an electric vacuum pump for removing blow-by fumes?

This would obviously increase emissions, but we don't have smog check in my area.

mishar

I've never seen any credible proof of carbon buildup on A8/S8 engine. RS4 is not the same engine. It has quite higher red line, probably more of piston/cylinder and valve/valve guide clearance and they are definitely more abused.

GnatGoSplat

Would the Q7 engine be the same as an A8?
I found this:
http://www.audizine.com/forum/showth...arbon-cleaning

Not as bad as some RS4 carbon pics I've seen, but definitely gunky.
On the other hand, if you only have to clean it every 90k, that might be infrequent enough not to be too terrible depending on how much work it is to pull the intake manifold.

mishar

That much carbon buildup doesn't matter at all. Power loss is barely measurable, definitely not noticeable. Cleaning it is pure waste of time and money. Of course one who payed for it would swear that his car goes much better, burns less gas and fly higher.

Mike911A8

I have owned a 2007 A8 since new. That was the first year DFI was fitted to the V8. The car now has 71,000 miles , with no indication of carbon buildup. I keep track of mileage on trips and the results are consistent. Never a CEL, and the engine is smooth as silk. I am a fanatic about the use of top tier gasoline and change the oil every 5000 miles. Mike