Greetings everyone! Just a few weeks ago, I got it in my head that I'd like to determine some formulas for the efficiency of an engine - particularly mine, a 1991 Geo Metro. The overall goal is to compare various acceleration rates to show how slower acceleration can produce greater gas mileage(and also to determine the lower bound to this trend - certainly accelerating for an hour to reach 25mph is not going to be very efficient!). Very quickly I learned that there are many, many factors involved with which I was not immediately familiar. Not the first of this being the many-layered approach to acceleration. Just wrapping my brain around concepts like http://en.wikipedia.org/wiki/Jerk_%28physics%29" [Broken], torque, air resistance, and internal friction in enough to make my head spin! Suffice to say, I've uploaded https://spreadsheets.google.com/ccc...hzT284VUxhRmd3YXg0dXc&hl=en&authkey=CPSJv-0J" that's quite a mess right now. I haven't accounted for many, many factors - and some of the initial calculations (although they appear correct) seem to imply that you can get better gas mileage by accelerating faster! Clearly there's quite a bit wrong with this. However, I'll be working on it. I've also opened up permission for anyone to edit the file, if they feel like being generous and helping out. Updates to the file and such will be posted here. Cheers!