compression ratio ????

[mudseeker]

do these look like good numbers for high octane pump gas or should i bump it down some? oh, and it will be a NA engine.

edit: dang that picture is small. basically came out to 11:1 compression.

[tanz45]

Found on webs

5:1 72 -
6:1 81 25 %
7:1 87 28 %
8:1 92 30 %
9:1 96 32 %
10:1 100 33 %
11:1 104 34 %
12:1 108 35 %

Modern engines have improved significantly on this, and the changing fuel specifications and engine design should see more improvements, but significant gains may have to await improved engine materials and fuels.

Based on this information I extrapolated the following expansion of the octane chart

DCR Octane #
7.1 87.5
7.2 88.0
7.3 88.5
7.4 89.0
7.5 89.5
7.6 90.0
7.7 90.5
7.8 91.0
7.9 91.5
8.0 92.0
8.1 92.4
8.2 92.8
8.3 93.2

But tuned properly and you can run a lower octane.