I understand that later model classic A3s (such as my MY01) have a significantly different engine incorporating VVT (variable valve timing), a different turbo and some other bits and pieces.

Does anyone here have some documentation on this engine? I'm curious to see any schematics, details of what changed from the non-VVT engine, how the VVT is controlled etc.

Thanks in advance.... let me know if you'd rather email stuff rather than posting it here.

Checkout audi tuning specialist Jabbasport ;
http://www.jabbasport.co.uk/

Select Audi modifications then A3 model. Here you will see they make reference to the different engine types and the differences power outputs that can be extracted.