- SOPHOMORE = SOPHOS + MOROS = “wise” + “foolish” (Greek)
- I just learned that (1) Thomas Crapper did not invent the toilet, and (2) the word “crap” does not come from his name. Now I feel totally disillusioned about my knowledge base. Bummer!
- My car takes 91 octane. Gas is sold locally in octanes 87, 89 and 92 or 93 octane. So I must average octanes. One would think that gas stations would have figured this arbitrage out. But it is always strictly more profitable for me to mix 92 and 87 octane than 92 and 89 octane. So drivers: avoid 89 octane!
- I am such a sucker for Venn diagrams. This one categorizing all drugs is for the ages.
Disclaimer: For me, caffeine is a stimulant and alcohol is a depressant (my nightly glass of red wine, angel face). I have had nitrous oxide (hallucinogen & depressant) two or three times. I have fended off the peer pressure to consume all others – does that make me a geek or a nerd? Curiously, cannabis – or marijuana (Mary Jane) – is simultaneously a stimulant, hallucinogen, depressant, & anti-psychotic.
Cheap Talk
A blog about economics, politics and the random interests of forty-something professors
Cheap Talk 
6 comments
Comments feed for this article
June 25, 2011 at 11:43 am
twicker
Quick note re: the car: if you want to run it w/92 or 93 octane, that would be fine for your engine; the “91 octane” rating is a minimum, not an absolute.
BTW, I’d be careful about mixing/matching 87 & 92 octane; your car’s computer is continually trying to figure out the optimal burn for your car based on the average burn over the past X amount of time, which depends further on the octane of the gas. If you stay at one octane level (e.g., 92), then it figures it out pretty readily because there’s not a lot of random variation in the octane level. If, however, you’re continually changing up octanes, then there’s a lot of variation in the octane and your performance (and fuel efficiency) is likely to suffer. In other words, by trying to beat the numbers and do a mix-your-own 91 octane rating, you’re likely reducing your efficiency and causing extra wear & tear on your engine. It would likely be cheaper overall (because of buying less fuel) to just buy the cheapest 92 octane you can get and leave it there (and just sticking to 89 octane might be ok, depending on the car; it does have some risk of causing the engine to run hotter than it otherwise would, but it really depends upon the engine itself).
June 25, 2011 at 12:11 pm
Franz
87 octane, wow. The lowest you can get in many European countries is 95 octane, used to be 91 a few years ago.
June 25, 2011 at 2:31 pm
Lones
I am no car guy, but this is high octane commentary! Assume I am damn good at creating 91 octane since I understand fractions, and am willing to put up with the hassle of doing two gas purchases. I have wondered if the gain in mileage from simply using 92 octane gas justifies the higher price? It seems in this range that, for instance, 10 cents separates 87 and 89 octane, while 92 octane costs and extra 13 or so cents (speaking to the arbitrage I alluded to). So I perhaps only save 4 cents a gallon by using my 91 octane creation, or 1%. Damn, this is making me look like a cheapskate!
June 27, 2011 at 3:15 pm
Alan Gunn
I’m struck by the precision of your car’s preference for a particular octane. For most cars, the rule of thumb is run it on regular unless it starts making funny noises, in which case try the next level up. (This may change with the addition of more ethanol, as higher octane is said to counteract some of the bad things ethanol does to some engines). You drive something exotic?
June 28, 2011 at 12:48 pm
Lones
I am just reading and trying to follow the manual. I drive an Infiniti G37X. Hardly exotic. Its intelligent all-wheel drive keeps me from getting stuck on snowy Madison hills — which my old Jetta did!
June 28, 2011 at 2:13 pm
Alan Gunn
Yeah, but if you look at the care labels on your clothes they all say something like “have this hand washed by virgins in cold water with no soap,” but you can really just toss it into the machine. My car’s manual says to use mid-grade, but even the dealer told me to just use regular unless I had a problem, which I haven’t had in four years. I think the idea is that if you complain about something they can say you abused the car, but if you know this you won’t fall for that.