BBC America’s “Orphan Black” saw huge gains in time-shifted viewing for last week’s second-season premiere, adding to its already series-best numbers.

According to Nielsen estimates that include three days worth of DVR playback, “Orphan Black” doubled its overall audience — from 369,000 to 738,000 — while rising 91% in adults 18-49 (391,000 to 746,000).

Generally speaking, shows with smaller audiences tend to see bigger percentage gains than more popular ones, but the 91% lift in 18-49 for “Orphan Black” is the largest for any cable-drama season premiere this season. FX’s “The Americans” saw a 81% rise, and was followed by USA’s “White Collar” (78%), FX’s “Fargo” (74%), AMC’s “Mad Men” (74%) and Lifetime’s “Drop Dead Diva” (73%).

Similarly, the 100% lift in total viewers for “Orphan Black” was great than that of the premieres of “The Americans” (72%), Cinemax’s “Banshee” (68%), “Fargo” (68%), Starz’ “Black Sails” (64%) and “Mad Men” (62%).

The cume number for the Saturday, April 19 premiere and three repeats airing over the ensuing 24 hours now stands at 1.577 million, including 909,000 adults 18-49 and 927,000 adults 25-54. In adults 18-49, “Orphan Black” ranks second among BBC America series, behind only “Doctor Who.”

According to Nielsen SocialGuide, “Orphan Black” was also the No. 1 television show on Twitter for the day of its premiere, and was the No. 1 basic cable drama on Twitter for the week.

In other L3 updates, WGN America’s series premiere of “Salem” last Sunday grew its 18-49 audience by 56% (1.008 million vs. 647,000) and 41% in total viewers (2.145 million vs. 1.5 million). And combined, its four telecasts on the night grew by 51% in adults 18-49 (1.3 million vs. 886,000) and by 36% in total viewers (3.1 million vs. 2.3 million).

And at AMC, the season’s second episode of “Mad Men” showed more significant time-shifting than the premiere: It grew 99% in adults 18-49 in L3 (to 1.6 million) and by 110% in adults 25-54 (1.8 million). And in total viewers, it spiked 74% to 3.3 million.

HBO notes that “Mad Men” remains the No. 1 season pass show on iTunes, and this episode is currently No. 6 on the list of top TV episodes.