Octane Differences

Question

Octane Differences

brute29 (Mechanical)

(OP)

28 Sep 03 22:14

What is the advantage in 91 octane compared to 85.5 octane?

patprimmer (Publican) · Answer 1 · 2003-09-28 23:54:01

Simply, you can run higher compression ratio while retaining optimum spark advance, and thus get more power.

You can do a long involved study with various manipulations of the 3 variables of octane rateing, CR and spark advance, but I expect that you will come up with about 9:1 for 91 octane and about 8.5:1 for 85 octane, with both likeing about the manufacturers spec for spark advance

Regards
pat

kmpillai (Mechanical) · Answer 2 · 2003-09-29 01:01:32

Higher Octane fuels means better knock reistance. But an engine having a fixed compression ratio works well using octane 85.5, then it is not required to go for octane 91. Since increase in octane number will raise the fuel cost also.

Come Join Us!

Posting Guidelines

Octane Differences