Both managers made two changes at the break and it was Norwich who benefitted as substitute Slimane came on to cause all sorts of problems for West Brom.
Just four minutes into the second half he showed great footwork to chop back inside and lay the ball off for Ahmed whose first time effort from 12 yards found the top corner.
It was nearly 3-0 a moment later as Slimane again caused panic in the West Brom defence, finding Kellen Fisher but his effort was well saved by home goalkeeper Josh Griffiths.
Iling-Junior then called Norwich stopper Vladan Kovačević into action shortly after the hour mark with another powerful strike from the edge of the box but the Bosnian goalkeeper did well to tip the shot over the bar.
Norwich made it 3-0 with 20 minutes remaining with Slimane, following up on his own initial effort which Griffiths had pushed on to the post, slammed the ball into the net with home defenders caught on their heels.
A few minutes later Norwich got their fourth as the hosts again failed to deal with a loose ball in their box, allowing Chrisene to smash his effort into the roof of the net.
West Brom were all at sea as the clock ticked down, with Norwich looking dangerous every time they broke up the park and they did add a fifth late on as substitutes Papa Diallo and Kvistgaarden combined in the box before the Danish striker prodded the ball into the net.
After losing his first match in charge 3-2 to Middlesbrough on Friday, Ramsay has now tasted defeat in his opening two games as Baggies boss and his side are in action again on Friday evening away at Derby.
