octane
#1
octane
what grade gas do you all use in your civics? i just put some 91 octane gas in my GFs civic, and she got all pissed at me and said it was too high octane, that she 's only supposed to use regular 87 octane gas. is there any reason not to use a higher octane gas?
#4
RE: octane
The octane rating of gas refers to the percentage of octance (C8H18 I believe) in the gasoline mixture. 87 octane gas contains 87% octane, 89 contains 89%, etc. The rest of the gasoline mixture usually contains heptane (C7H16 I believe). Octane gas can be compressed quite a bit before it spontaneously ignites (engine knocking), but heptane gas spontaneously ignites very easily when compressed. So, the higher your compression ratio is, the higher octane gas you should get to prevent prevent preignition. For example, my Mini Cooper S has a supercharger, so I cannot get gas with an octane rating of lower than 91.
#6
RE: octane
I use midgrade in my civic and premium in my S15 (for obvious reasons). There is actually a noticeable difference between regular and midgrade in terms of gas mileage and pickup. Just personal preference. But yeah, when it's $1.97 a gallon for regular, it can be a little steep to use higher grade gas.
#9
RE: octane
tomuch octane can burn ur heads and cause other damage on ur car in a civic u should use 87