what is the minimum octane fuel that can be run e320
You know Joe I would recommend running the recommended fuel. For one thing the fuel economy with the recommended grade might be better enough to offset the cost of using regular. More importantly perhaps, running a lower than recommended octane could raise reliability issues in the engine. You went for the Benz and it usually makes sense to protect the investment by giving it what it was designed to run with. Good luck!
Search Mercedes-Benz E-Class Questions
Mercedes-Benz E-Class Experts