With the turbo the clutch was slipping very badly even on only 200mbar of boost pressure. I suspected that the clutch was worn out after 125k miles of service. I brought a new one that is supposed to have a better (more grippy) friction material and stronger spring pressure. I changed this myself and it wasn’t easiest thing to do. When I plan major car maintenance it always seems to rain heavily all day. The release bearing was also wrong which needed some modification with the welder to get it to work properly. Here's a picture of my legs having a bad time under the car during a break in the weather:

After about 12 hours it was done and there is no more sipping. The performance of the car is much better now, even running on only 250mbar. I plan to run at about 500-600mbar when the piggyback engine controller is finished. See next post.