So setting them @ 172 bar was the key huh?
Was the 2500 psi a good spray with just reg diesel or did you test it?
it was really easy to make all the injectors hit 2500 psi ( i got them all within 10 psi of each other ) . ( if they wanted to be at 2550 , or 2450 , that is where they would be , i don't think there is much difference in the spray pattern between 2400- 2600 psi )
once i got over 2300 psi with the merc nozzels and straight diesel , the spray got much finer and more of a vapour .
2600 psi looked alot like the spray at 2500 psi
the above was with straight diesel .....
we where lighting paper towel on fire outside , then spraying it for fun

.
the fire ball lit off much quicker with the higher pop presures .
with veg oil mix and waste motor / diesel mixes , the lower pop presures actually put out the paper towel . it wasn't until i got over 2400 psi that the spray got fine enough that the mist ( if you want to call it a mist ) would slowly light off .
as for spraying heated veg oil ...... i'm still trying to figure out how to pull that off ...... without damaging the porta power i'm using for a tester .
i'm thinking maybe submerging the injector and line into some boiling water till it's all the same temp . that would allow the porta power to remain cool , but i would only get one or 2 " squirts " out of the injector till i got cold oil in it again .
i'm working 3 jobs right now , so my play time is limited , but i want to do a test of veg oil before i finish my veg oil conversion on my jetta ( i'm about 90% done now ).