Woops, my mistake!
It takes 5mins to figure out. Take off ur tb and measure it. I believe the tb on a ka is 55mm.
A USDM VG30E TB is 56MM interior diameter port matched to manifold. Exterior taper I believe is 60MM
A USDM KA24E/DE TB is 60mm interior diameter port matched to manifold. Exterior taper I believe is 66MM. Maximum porting to the KA24 TB is 65MM maximum porting diameter (this means use of a 65MM butterfly).
PIC of an OBD2 USDM KA24de TB 66mm taper to 60mm butterflyWe never received the RB30e in the states but I am quick to assume that it uses the same TB as the VG30e engine same bolt configurations for swapping. I would like to note that VG30e engines when using the KA24 TB show gains of HP and torque across the board. I'm researching to see if I can also use the KA TB on my VG33e engine which comes in my 2003 nissan pickup truck. If you want the bolt configuration measurement and layout let me know. I have more pics.
All USDM and JDM (Manufactured in Mexico and Japan) KA TB's are 60MM/butterfly.