CalG

Mance

Do you feel that the "shrouding" around the injector area of the heads you have discovered, is in some way related to the spray pattern of the Lucas injectors?
Some kind of "turbulator", or even just a "blast shield"?

The spray pattern of the Lucas injectors sure appears to be unique in its straight shot shape.

CalG

VAP

cast obstructions in the heads intake ports, being able to deliver their tightly focused fuel stream past the port obstructions without contact. The stock injectors conversely, with their wide-dispersal, inverted cone pattern are the ones severely compromised via 50% of their spray pattern contacting the obstructions with the accompanying fuel deflection, & splattering. The stock injectors were only able to deliver approximately 50% of their atomized fuel mist to the intake valve area with an accompanying stream of fuel following each injector pulse then large droplet dripping that followed the stream.

All intake ports would suffer from diminished air flow due to the obstructions.

Audi never planned on a tight, "jet-stream" injector being used so I doubt there is any "related" cause/effect at work here. And if there is it would seem the Lucas is a cure rather than the ail.

Don't forget it was the RCE/Lucas injectors that worked fine in my flow testing with this discovery. Their fuel stream missed the obstructions altogether. It was the stock Audi injectors (Hitachi) that had problems with the port obstructions.