wow, this has got very confusing.
Ok, as far as I am aware, if you have ABS, then you will need A NON ABS proportioning valve.
If you are swapping in rear disks on a car that has rear drums, you will need to get the correct proporioning valve.
For example.
I have a UK EJ8.
The MC size is 15/16 (yes this is the same size as all uk vti, EM1/EK4 and even 96-98spec JDM Integra and also JDM AND UK EG5/6)
The car came with 262 front disks and 242 rear drums.
I intend to swap in a 242 rear disk swap. (From an eg5)
HOWEVER!!!!!!!!!!!!!!!!!!!!!!!!!
I will still need to source a UK VTI (ek4/em1 or even an ek9 I belive) PROPORTIONING VALVE!
WHY????
Because ( I am told) the pressure sent to the drums is more than is required for the disk swap, and so, if I leave in place the standard EJ8 prop valve I will not have the correct distribustion of braking force to the rear of the car. It will be more than is required.
Now, as for SI/EX/CX whatever these cars are, may I please ask that we talk in model codes as It will simplify the reading for everyone, in europe and the US.