Friday, March 21, 2008

Saving Gas and Cutting Spam

I got one of many forwarded emails from a dear family member, but this time I could not resist answering in the hopes that they learn to use Snopes and other resources while practicing some basic email spam hygiene:

Almost everything in this email about gas fueling tips is the usual mass email spam garbage you can expect to read on Teh Internets:

1) The temperature variation is not an issue mostly because the percentage variation is not enough to cost you an amount of money worth worrying about.

At $4.00 per gallon a 1% increase in volume due to temperature for a customer using 20 gallons a week (about what I use driving to work each week) would save about $60 a year by buying gas in the 'cool' hours. Note that a 1% volume change is a wildly unlikely large amount of change since the volume of gasoline changes 1% with every 9°C [48°F]. So not only are you not saving enough money to make it worth the effort if the volume really changes that much, most of the time the volume is not going to be changing that much so you are not going to be saving anything at all.

2) A similar calculation as above can be applied to the vapor recovery argument except the numbers for the volume of fuel 'lost' to the vapor recovery system would be in the very small fractions of a percent. This makes it even less worth the effort to worry about.

3) Let's just repeat the calculation for the 'only fill your tank when it is half empty to reduce evaporation losses'. These are likewise as above ridiculously small amounts when calculated against automobile gas tanks. Evaporation losses might be a concern for huge fuel storage tanks, but they are not not important for passenger vehicles.

4) You also do not have to worry about filling up right after a delivery from a fuel tanker to you local filling station. Trash in the tanks has a long pipe to climb before getting to your car, every pump you fill your car from has filters that keep most of that trash from getting into you tank, and your car has a filter that keeps the rest from getting into your engine.

None of these tips is going to save you nearly as much as just going to the station with lowest price every time you fill up. That is a lot easier to do than any of them.

You should enjoy the time you save ignoring these silly worries and skipping all of this crap that is forwarded to you from anonymous idiots on Teh Internets.

Helpful hints on a stress free life from your loving nephew (or cousin or invisible internet friend, whichever applies).

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