these are funny motors, first 2 stage vtec is for economy, not performance.

there are 4 d15b

the most common d15b is the vtec model closest to the d16z6. same head, shorter stroke.

d15b non vtec (have one in my car) same as a d16z6 (just z6 bottom end with a shorter stroke) and a d15b7 head

d15b 2 stage vtec - has a vtec that engages between 0 and 2500 rpms (it turns off 4 intake valves and leans out fuel mixture to get really good highway), and the second stage that engages about 4800 more for performance

d15b 3 stage vtec has a vtec that engages between 0 and 2500 rpms (it turns off 4 intake valves and leans out fuel mixture to get really good highway), and the second stage that engages about 3500 - 4600 more for performance, and the last that engages from 4600 to red line. most would say the normal cam profile is useless. remember your engine must be at correct operating temperature and have the correct oil pressure for the vtec solenoid to engages.

unless you find an advance controller that can turn on and off vtec throughout an rpm range, it is quite useless. find the correct ecu and pin for vtec.