I’ve read (and even saw a youtube video) of people using Seafoam to clear out the carbon buildup. I’m not sure if that’s really a good idea or not though, that stuff is pretty aggressive.
Walnut shells and media blast kit
Audi used to use that method and then abruptly stopped.
BMW uses that still.
Taking the IM off so I can get to the valves. Saw where a guy used zip ties and a drill I wonder what keeps the crap falling in the cylinders.
Saki, interesting info
Ssicks, there are different ways to do it, so hopefully youll get some more suggestions.
Here is a pretty good writeup for an S8 that was cleaned (valves and intake)
http://www.fluidmotorunion.com/archives/18041
Heat soak in this car is killer. Too much hot aluminum in a confined space. Spark plugs are straight forward if I remember right.
Agreed on the heat. I took my car to the dealer and it sat in the lot for 15min. I started it up and let it idle. Opened the hood for the service manager to check something, and the heat coming off the engine was noticeable and extreme.
I asked him if that was normal, thinking he would say no, but he just kinda sighed and said yes, it was normal.
That is why I think it is so important to do something with the cats. They are restrictive and up close to the engine (two of them are very close). We have to do everything we can to cool these engines down, and let them flow better. Gutting the cats and replacing with high flow units downstream (or test pipe if your car is track only), or even better, headers and high flow cat relocation. Add in intake spacers too for lower temps in the intake manifold.
The other huge plus with this plan is that it is no longer an engine drop to replace the upper cats and o2 sensors after you relocate them. So, if you have to go in there once for that job, then you should do this to avoid it again in the future. And even if you do it ahead of time, well, you can guess that you would have had to go in there at some point anyway, if you plan to keep the car for any significant amount of time.
Better flow and lower temps may also help with carbon build up and cylinder wall scoring. It is realy WIN WIN WIN all around. Costs some money up front to do it right, but saves in the long run IMHO (will test with my car).
A tune will be needed to account for the changes.