Brock's Performance Forum : Race fuels vs octane & AFR https://forums.brocksperformance.com/ Copyright (c) 2006-2013 Web Wiz Forums - All Rights Reserved. Mon, 05 Oct 2026 13:14:26 +0000 Fri, 04 Oct 2019 09:00:09 +0000 http://blogs.law.harvard.edu/tech/rss Web Wiz Forums 12.01 360 https://forums.brocksperformance.com/RSS_post_feed.asp?TID=2610 <![CDATA[Brock's Performance Forum]]> https://forums.brocksperformance.com/forum_images/web_wiz_forums_black.png https://forums.brocksperformance.com/ <![CDATA[Race fuels vs octane & AFR : Frederick, I would stick with...]]> https://forums.brocksperformance.com/forum_posts.asp?TID=2610&PID=10798&title=race-fuels-vs-octane-afr#10798 Author: Steve6
Subject: 2610
Posted: October/04/2019 at 9:00am

Frederick, I would stick with the 95.  Just remember you are using the RON scale, we use the RON + MON/2.  And 95 RON is approximately 91 on our scale, and on the ZX14s we run 89, so that is very close.
]]> Fri, 04 Oct 2019 09:00:09 +0000 https://forums.brocksperformance.com/forum_posts.asp?TID=2610&PID=10798&title=race-fuels-vs-octane-afr#10798 <![CDATA[Race fuels vs octane & AFR : I&#039;ve been reading much about...]]> https://forums.brocksperformance.com/forum_posts.asp?TID=2610&PID=10797&title=race-fuels-vs-octane-afr#10797 Author: Frederick
Subject: 2610
Posted: October/04/2019 at 7:25am

I've been reading much about how higher octane fuels cause a drop in performance because of the slower burn rate of the fuel. In my part of the world the lowest octane pump fuel available is 95 octane...already much higher than the recommended octane in your parts.  
Race fuels available is the 24/7 race fuels. 102 unleaded mildly oxygenated and 109 unleadedhighly oxygenated.  Oxygen content is 3,6 and 3,8. Since our pump gas is slow burning already i keep entertaining the thought of the oxygenated race fuel...the oxygenates in the fuel should make it a better fuel than our 95 pump gas in my mind...am I wrong?

Was also wondering, how does AFR relates to octane.  If you get a best performance on 87 octane running say a 13,1 AFR...then running 95 octane would mean that 13,1 AFR would be useless, would i not want an AFR with an higher air ratio with the higher octane fuel?
Similarly...if my best performance come from say a given AFR of 13,1 on pump gas...will it be 13,1 for oxygenated race fuels too or will it become something like a 12,8.

Was just thinking, if AFR is octane sensitive then the Brock's maps wont do much for us in my part of the world?
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