Curious.   My other German vehicle in the past, it was fine-tuned by the
engine builder on a Mustang chassis dyno...every modification we added
entailed another trip to the dyno and repeated runs..This was (I think) a
Motronic EFI at that time...One of the tricks this engineer used was the
adjustable rate fuel pressure regulator...he would vary the fuel pressure
by "so many flats" on the adjustment control bolt and gain up to 20hp with
that alone....on a 415hp motor, but still...worth doing...

   I surmise it has to do with the injector spray pattern, but there could
have been something else happening too.   We had no way to control the
pulse length...I don't think.....I was more concerned with the whole
package of racing the car and left the motor pretty much up to him while I
worked mosty on the suspension and my racing skills.

  It might be worth trying one of those if anyone has access to a dyno to
mess with it....  Just recalling from the past...

  Don Hanson