Ronchi, who opened the innings for the visitors, struck a 112-ball 107 to counter Mumbai's spin bowling that dominated the third and final day's play at Feroz Shah Kotla.
Ronchi's opening partner Martin Guptill fell for nought as the Kiwi batting suffered from lack of partnerships on a pitch that seemed to be taking vicious turn.
New Zealand innings folded in the fourth of the mandatory 15 overs in the last hour of play, but Mumbai did not take up the chase of 96 in nine overs.
The Aditya Tare-led Mumbai, who started on their overnight score of 431 for five, declared their first innings on 464 for eight with Siddesh Lad unbeaten on 100.
Earlier the visiting batsmen also got some crucial batting practice on the opening day with skipper Kane Williamson and Tom Latham registering half-centuries.
The two sides played with 15 members each, with 11 allowed to bat and field in the only warm-up tie before the first of the three Tests starting September 22 in Kanpur.
Brief Scores:
New Zealanders 324/7 dec and 235 all out in 66.4 overs (Luke Ronchi 107, BJ Watling 43; Parikshit Valsangkar 3-41)
Mumbai 464/8 dec (Kaustubh Pawar 100 retired out, Suryakumar Yadav 103, Siddhesh Lad 100 not out; Ish Sodhi 2-132)