Thread: Octane question
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Old 10-11-2013, 11:18 AM   #11

mcdoogle6969's Avatar
Drives: 2010 Camaro SS, 2008 Heritage 300C
Join Date: Jun 2009
Location: Wisconsin
Posts: 1,912
Originally Posted by Iam Broke View Post
You could always splash in your own ethanol with E85 to raise the octane a few points.

There is a calculator online at to determine the octane/percentage blending your own.

The stock fuel system can handle a 1:1 blend (E47) but you need a tune for anything over around 30% ethanol to keep from popping a CEL for excessive positive fuel trims. The fuel trims adjust for the extra fuel needed after driving a few miles and the fueling carries over into the WOT fueling for positive fuel trims also. I ran 30% E with no issues when I was stock.

Avoid leaded race fuel as it will destroy your O2 sensors over a short time.
I'm far from anywhere near stock. My 02 sensors are tuned out. Running the squash return style fuel system. I'm going to be running two tunes. Ones on pump gas, other is pullied with c16. I'm just trying to figure out what I should run for pump gas. I'm going to have to search around and see if there's any place around here with 93 still.
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