When taking ACE inhibitors to lower your blood pressure it can take between 1 to 12 hours to see your blood pressure lowered and go down after you do take your ACE Inhibitors.
After 1 to 12 hours of taking the ACE Inhibitors of a dosage of 11/6 mm Hg you should notice your blood pressure lowered.
If not then you need to speak with your doctor.
When I started taking ACE Inhibitors my blood pressure started going down within a few hours and as long as I continued taking the ACE Inhibitors like I was supposed to my blood pressure stayed lowered.
You can also help lower your blood pressure by avoiding stress, taking a walk, running, jogging etc.