It will depend on the variety of pepper.
Type (Sweet Pepper or HOT
Climatic conditions (hot/cool/wet/dry/humid)
and amount of sunlight the plants receive.
Night time temps are the main factor:
Optimum Temps for sweet Pepper flowering, pollination, fruit set is aprox. 60Ã‚Â°
while Hot pepper varieties should be between 65 and 80Ã‚Â°
night time temps over 80Ã‚Â° causes blossom drop
Day time temps over 95Ã‚Â° and the pollen will abort and the fruit set will be reduced
It should also be said that the plants will produce many more flowers than actual peppers, doing as Kisal suggested is a great Idea, and great for a few plants... if you have many plants..
(we only have 125 this year, last year 186)
you just have to go with Mother nature and hope for the help of your Pollinators
To sum it up:
All key factors in place, from the time you have a blossom, to the time you should see a very small immature fruit forming..
about 10-14 days, at least thats my experience here in Minnesota.
Good Luck, I'm sure your patience will be rewarded with many tasty peppers