I had twittered about giving my car premium gas after it passed 100,000 miles, and Christian Montoya emailed me this note which I think you guys might find interesting:

I just wanted to let you know that this is a dangerous thing! The difference between regular, plus and premium gas is the octane rating… 87, 91, and 93 if I remember correctly. Every car has its own rating, and I am going to guess that your car is 87 or 91. A lot of people think that giving a car a higher grade of gas is a way to give it “extra treatment,” but this couldn’t be farther from the truth. The higher octane rating means that the gas *burns hotter*, and if you give an 87 octane car 93 octane gas, you are making the combustion process burn much hotter than what the engine is designed to handle, making the car wear out much faster! If you gave your car premium gas every day it would wear out sooner than expected, and giving it premium gas even one day (like a birthday) is not a present at all. If you want your car to last as long as possible, stick to the octane rating it calls for.

I hope this helps! From a reader (and engineer) to you… no more Premium, okay?

Update: Be sure to check out the comments, a ton of great feedback.