During my usual bored nothing else better to do trawl through the internet I came across this self study on the S4 engine and it's brilliant! Someone's put a lot of work into producing this, could possibly be an Audi document, so thought I'd share it with you all, only had a quick browse through and barely scratched the surface of the wealth of information contained. Handy for explaining anything to do with the workings of this great engine, identifiying parts and what they do, wiring diagrams and a ton of excellent cut away drawings. I could go on but take a look yourselves, I'm sure you won't be dissappointed! Also please feel free to post this elsewhere, maybe summit more permanent for future reference for all.