Hey the difference between 87 and 91+ octane is only $70 a year for something you just have or will pay $40K for. Don't you think champagne would be more suitable than Pabst Blue Ribbon! BTW, there's an octane sensor on the X that retards the spark with lower octane so you may save some money but you will accelerate more slowly. As msu suggested, there are numerous threads we folks in the Class of 2001 discussed and analyzed the heck out of this issue so do some research if you want to learn more.sgbingham said:What really happens to the MD-X if you DON'T buy premium gas and go for the 87 octane regular unleaded?
There may be a difference in mileage, but I don't think anyone has claimed it is as much as 20%. It certainly hasn't been for me (more like 5%, if at all). However, the difference between 87 and 91 octane is 20% around here, so it definitely isn't a wash. As long as I'm not operating in a 'severe' environment (towing, etc.), I would rather save $100/year and put it on better oil and other things that Big Red needs.DaleB said:Ironically, if the spark is retarding to avoid detonation, there is a darn good chance the efficiency of the engine is reduced and your mileage will be slightly worse. So you have saved virtually nothing.