Dynamic Compression Ratio versus Octane
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It is my understanding that optimum design dynamic compression ratio for 91 octane is from 7.5 to 8.5 with the sweet spot at 8.2:1.
What is the optimum dynamic compression ratio for 87 octane?
What is the optimum dynamic compression ratio for 87 octane?
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There are so many factors that go into this.
I am running 91 with a 9.5 ratio with no problems at all.
I am running 91 with a 9.5 ratio with no problems at all.
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Here are all the calculations you may need http://www.smokemup.com/auto_math/index.php
have to subscribe for the advanced stuff
Good info http://e30m3performance.com/myths/mo...comp_ratio.htm
and here
http://www.popularhotrodding.com/tec...on_ratio_tech/
have to subscribe for the advanced stuff
Good info http://e30m3performance.com/myths/mo...comp_ratio.htm
and here
http://www.popularhotrodding.com/tec...on_ratio_tech/
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there is no single answer. the fuel you can get away with is directly and specifically related to the ability of the combustion chamber to not develop hot spots that cause detonation. the ability to do that is a combination of the design of the cumbustion chamber itself as well as about 500 other variables... an 8 : 1 motor w/ a bad piston shape and cumbustion chamber will eat itself on 91 and a 10 :1 with a proper shape and design will live just fine...
there is NO single magic bean answer. it is all combination and design. for example.... most of the good bike motors are running 11.5 to 1 on pump gas... and i THINK the new kawasaki is higher than that... how do they do that ? easy... they know what they are doing.
a properly configured 9.4 :1 motor should run 91 all day... IF thats really what you are buying and IF the rest of the motor is configured properly.... a significant mistake in any one area , renders all your and calculations assumptions meaningless .
there is NO single magic bean answer. it is all combination and design. for example.... most of the good bike motors are running 11.5 to 1 on pump gas... and i THINK the new kawasaki is higher than that... how do they do that ? easy... they know what they are doing.
a properly configured 9.4 :1 motor should run 91 all day... IF thats really what you are buying and IF the rest of the motor is configured properly.... a significant mistake in any one area , renders all your and calculations assumptions meaningless .
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Originally Posted by Wobble
Here are all the calculations you may need http://www.smokemup.com/auto_math/index.php
have to subscribe for the advanced stuff
Good info http://e30m3performance.com/myths/mo...comp_ratio.htm
and here
http://www.popularhotrodding.com/tec...on_ratio_tech/
have to subscribe for the advanced stuff
Good info http://e30m3performance.com/myths/mo...comp_ratio.htm
and here
http://www.popularhotrodding.com/tec...on_ratio_tech/
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TomZ
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02-18-2003 09:56 PM