Is there a supercharger that will fit on an BMW 840ci?

Yes, there are aftermarket supercharger kits available for the BMW 840Ci, specifically designed for its engine. Brands like ESS Tuning and Vortech offer supercharger systems that can enhance performance significantly. It's important to ensure compatibility with your specific model year and to consider professional installation for optimal results. Always check for any warranty implications or modifications that may affect your vehicle's reliability.