Oh, and if using motor gasoline as white gas, buy it in the summer (in places that have a winter) because summer-blend gasoline is lower volatility (more towards white gas) with Reid Vapor Pressures of 7.8 to 9 psi while winter blends can be as high as 15 psi*.
*yes, it would seem that 15 psi “vapor pressure” means it would be boiling, but RVP is measured at 100F and in winter the gasoline in transport, storage and use would always be below that.
Bonus tip: when driving your car in winter, from say, San Jose to Tahoe, plan to full up in Tahoe when you arrive so you get winter-blend gasoline for easier starting and smoother running.
Bonus tip#2: when carrying lots of backpackers from Berkeley to the Sierra in the summer, I’d top off before leaving the Central Valley both to get the lower price, but also to get the 87-octane “regular” rather than the 85-octane “regular” at elevation. Â Usually the 85-octane high-elevation “regular” worked fine at elevation, but with a heavy load and steep climbs, I’d get a little knocking with the lower-octane fuel.

