---------------------------------------------------------- Engines-List Digest Archive --- Total Messages Posted Fri 05/15/09: 1 ---------------------------------------------------------- Today's Message Index: ---------------------- 1. 06:58 AM - Re: Auto Engine - compression ratio vs. octane (Noel) ________________________________ Message 1 _____________________________________ Time: 06:58:01 AM PST US From: "Noel" Subject: RE: Engines-List: Auto Engine - compression ratio vs. octane I had a friend who regularly ran his 426 Hemi Charger on high octane Avgas before the advent of 100 LL. Noel -----Original Message----- From: owner-engines-list-server@matronics.com [mailto:owner-engines-list-server@matronics.com] On Behalf Of DEAN PSIROPOULOS Sent: 15 May 2009 01:14 AM Subject: RE: Engines-List: Auto Engine - compression ratio vs. octane The big automotive engines of the 1960s took compression ratios to their ultimate state of the art with premium leaded auto gas. Ratios from 10.5 to 11.5 to 1 were common place with 100 octane auto fuel. Since the unleaded mandate, computer analysis has advanced the state of the art in combustion chamber technology so that 9.5 to 1 ratios are possible on regular unleaded fuel (87 octane) without detonation. If you use computerized engine control with knock sensing you could probably go even higher. And with avgas being the equivalent of somewhere around 110 octane autofuel, the sky should be the limit (not quite but it would be an interesting exercise to see how high one could go using a modern auto engine with avgas). Dean Psiropoulos RV-6A N197DM Struggling with erratic idle on 0-360 ------------------------------------------------------------------------------------- Other Matronics Email List Services ------------------------------------------------------------------------------------- Post A New Message engines-list@matronics.com UN/SUBSCRIBE http://www.matronics.com/subscription List FAQ http://www.matronics.com/FAQ/Engines-List.htm Web Forum Interface To Lists http://forums.matronics.com Matronics List Wiki http://wiki.matronics.com Full Archive Search Engine http://www.matronics.com/search 7-Day List Browse http://www.matronics.com/browse/engines-list Browse Digests http://www.matronics.com/digest/engines-list Browse Other Lists http://www.matronics.com/browse Live Online Chat! http://www.matronics.com/chat Archive Downloading http://www.matronics.com/archives Photo Share http://www.matronics.com/photoshare Other Email Lists http://www.matronics.com/emaillists Contributions http://www.matronics.com/contribution ------------------------------------------------------------------------------------- These Email List Services are sponsored solely by Matronics and through the generous Contributions of its members.