# NU-B question.. Very simple

**URL:** <https://forums.speedlife.net/t/nu-b-question-very-simple/113812>\
**Category:** SON240sx Automotive\
**Created:** [March 12, 2008, 7:47am UTC](https://forums.speedlife.net/t/nu-b-question-very-simple/113812 "2008-03-12T07:47:19Z")\
**Posts on this page:** 3\
**Page:** 2

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**Author:** ![kimmerkaze](https://avatars.discourse-cdn.com/v4/letter/k/9d8465/32.png) [@kimmerkaze](https://forums.speedlife.net/u/kimmerkaze)\
**Post date:** [March 24, 2008, 9:00pm UTC](https://forums.speedlife.net/t/nu-b-question-very-simple/113812/21 "2008-03-24T21:00:00Z")

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> [@blown turbo thoeries](https://forums.speedlife.net/t/blown-turbo-thoeries/16342/9):
>
> i dont wanna be a jerk but  
> 91oct in a N/A with regular compression ratios will give you absolutly no performance gain in fact it does the opposite The octane rating is a measure of the autoignition resistance of gasoline and other fuels used in spark-ignition internal combustion engines. It is a measure of anti-detonation of a gasoline or fuel. so the higher the octaine raiting the less your N/A will perform. on the other hand it will get you better mileage and burn cleaner just thought you should have some facts

^^just continuing a bit…so the chemical associated with autoignition resistance or anti-detonation is iso-octane, which we just know as octane. it’s reverse-logic: heptane is the chem that actually ignites and iso-octane does the opposite. so when you get 87 ref fuel that means you have 13% burnable product.

that’s why when your comp ratios go up, you go higher on octane so you have less ignitable substance to keep things stable and not as hot. now if you keep pressure constant and change ignitable volume %, when you have less heptane, the explosive stuff, you should lose a bit i suppose unless there’s something i’ve forgotten.

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**Author:** ![nd4boost](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/nd4boost/32/5627_2.png) [@nd4boost](https://forums.speedlife.net/u/nd4boost)\
**Post date:** [March 29, 2008, 7:49am UTC](https://forums.speedlife.net/t/nu-b-question-very-simple/113812/22 "2008-03-29T07:49:26Z")

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> [@kimmerkaze"](#):
>
> ^^just continuing a bit…so the chemical associated with autoignition resistance or anti-detonation is iso-octane, which we just know as octane. it’s reverse-logic: heptane is the chem that actually ignites and iso-octane does the opposite. so when you get 87 ref fuel that means you have 13% burnable product.
> 
> that’s why when your comp ratios go up, you go higher on octane so you have less ignitable substance to keep things stable and not as hot. now if you keep pressure constant and change ignitable volume %, when you have less heptane, the explosive stuff, you should lose a bit i suppose unless there’s something i’ve forgotten.

thank you a little backup

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**Author:** ![ZANZAN](https://avatars.discourse-cdn.com/v4/letter/z/f1d935/32.png) [@ZANZAN](https://forums.speedlife.net/u/ZANZAN)\
**Post date:** [March 29, 2008, 9:59am UTC](https://forums.speedlife.net/t/nu-b-question-very-simple/113812/23 "2008-03-29T09:59:04Z")

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Never the less yes you guys are right… You DO get better fuel milage using premium… I only got 430 km’s on reg… City driving…

P.S… Selling the s14 anyways so it all doesn’t really matter to me anymore… I did find the reponses, debates, and information really interesting thank you!! Check out my Zenki for sale!! It’s in the Cars for Sale forum…

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