Hello, sorry for my bad english, I have the following experience with these injectors:
the spray level delta with these injectors is 90 degrees .. the 1.8t versions (APX) have a spray level of 270 degrees delta.
That means: the injector sprays up and has to spray the valves but at a delta angle of 90 degrees it sprays downwards against the intake manifold !!
This means that your fuel-air mixture is not optimally homogeneous due to the formation of fluid on the surface of the intake manifold. This is difficult to compensate for with small loads.
See the picture in the appendix.
My solution to this problem is to turn this injectors (0280158124) in the intake bridge by 180 degrees, you have to partially grind the plug of the injector because it comes against the intake bridge and extend it with a mating connector and some cable.
My TVUB correction for Lambda 1, which I tried out, is as follows at 3bar, reg.
1,7408 1,1392 0,8160 0,6048 0,4416
yes delta is 90 degrees but gamma is ZERO degrees. meaning they actually should have straight spray. No benefit from turning them.
