Old man at the Benz dealership says he’s been driving the same car for a long time and usually only puts in 87 octane in sprinkled with 91 every few times. What problems could this cause? Do I have to put in 91?
Disclaimer: I’ve owned (paid off) the car for 6 years and do put in 91, but trying to cut costs.
Modern cars have knock sensors that will adjust the timing on the fly, but there is a limit of how far it can adjust. If the timing is fully retarded and the engine still knocks damage could occur. Retarding the timing also retards engine performance. Around here (LA) to go from regular to midgrade is .10/gallon and another.10 to go to premium. So you are saving .20/ gallon. Assuming a 20 gallon fill up you are saving $4.00. So save 4 bucks and you won’t get all of the performance you paid for. So if $4.00 is going to change your lifestyle may I suggest you sell your Benz (Audi, Porsche, Vette, etc.) and buy a Corolla. They run on 87.