Originally Posted by wisesoul
Every 10k miles I take a snake scope into the cylinder head and check on the valves. Most of the time I find relatively low carbon build up. Pretty much every Audi FSI engine has this problem to an extent. Does this prevent me from enjoying my car? Hell no. I think the minor inconvenience is worth it. Odd because sometimes I can't feel a discernible loss in power, but I still find carbon deposits. I'm also waiting for an effective solution. For now, this will do.
I really hope someone, some enthusiast, or some company can find a PERMANENT solution. There's actually a company that's doing some R&D with methanol injection. I elaborated on that on my reply to LarThal
. I really want a DD for winter and the RS4 got my vote.
Originally Posted by LarThaL
Nope, no fix. It is an early direct injection design and the carbon buildup is a result of several factors. The catch can addresses the issue of fuel getting into the crankcase and breakdown products reentering the intake through the crankcase venting system, but the greater culprit was the amount of valve overlap and the exposure of direct injected fuel to hot exhaust gases. It is not an issue apparently with forced induction direct injection motors, and Audi has since made some design changes to their NA direct injection engines (although I haven't kept up with this since leaving the Audi scene). I actually did my own carbon clean and posted details along the way up on Quattroworld. That carbon gunk is messy and you do lose some power as a result. Cleaning it is a straightforward but tedious process. You just have to look at it as a 20,000 mile "service".
That said, I have never had as much fun doing anything in any car, at any time, than I did driving my RS4 with 4 snow tires in a foot of fresh powder.
Not me, but you get the idea:
Now, that is fun especially in the snow.
Other RS4 guys are going for methanol injection, but the problem is that with the methanol injection, the intake ports and valves get injected at WOT. Some company in the Audi forum is trying to change that. It's currently in R&D in which they plan to inject the methanol not just at WOT, but AT ANY GIVEN TIME purely for valve cleaning purposes. This process will "bathe" the intake ports and valves with fuel and cleans it in the process, just like a port injected n/a vehicle. That hopefully should be the solution to the carbon build-up problem.