Auto supplier BorgWarner wants investors to know two things about electric cars. First, even without internal-combustion engines, they will still need specialized motors, transmissions, cabin heaters, and other BorgWarner wares. Second, they aren’t going to become commonplace anytime soon.

Eight years from now, pure electrics will make up between 2% and 3% of light-vehicle unit sales, predicts market researcher IHS Markit—a view that BorgWarner (ticker: BWA) backs, based on talks with car makers. Some 17% of cars will be…