Date registered: Jan 2007
Vehicle: 2005 C230K Sport Coupe 6-speed! And now a 2011 GLK 350 4Matic in Palladium Silver!
Location: South Porcupine, Ontario, Canada
Mentioned: 0 Post(s)
Quoted: 6 Post(s)
If you drive it like an old lady - that is, light throttle and never hit passing gear - odds are great you won't encounter any issues. If you do any type of spirited driving, including passing gear, a lower octane rating will cause the engine computer to retard ignition timing, resulting in a hit in power output in an effort to save the engine from pre-ignition. The problem is, it can only retard the ignition timing so much, and if it can't retard it enough, you can seriously damage the engine, mainly melted pistons and/or burned valves and seats. A repair bill for such damage can easily reach ~$7,000 to rebuild - provided you can find the parts - or more than half that with an engine sourced from a scrap yard. Unless you can legitimately save $7,000 in gas prices, it really isn't worth it. There are, however, plenty of choices of vehicles from manufacturers such as General Motors, Ford Motor Company, Fiat/Chrysler, Honda, Toyota, Hyundai, Kia etc. that don't require 91 octane.