Fuel Octane for LS2 vs LS3
Thread Starter
Drifting
Joined: Feb 2001
Posts: 1,539
Likes: 63
From: new ulm mn
Fuel Octane for LS2 vs LS3
FYI, just compared the fuel requirement section in the '07 and '08 owners manual. GM changed the wording a little bit. While the '07 says a little pinging is okay, the '08 says bring it in if it pings or knocks. This is all on 91 octane or better. They must have changed the factory tune enough to take care of that. I just found it interesting because my '07 will ping a little once in a while even with 93 octane.
Race Director
Joined: Mar 2005
Posts: 10,399
Likes: 25
From: Austin Texas
There are lots of variables in Octane and just as many variables in how your specific car responds to conditions.
'Vettes are built to run best on at least 91 Octane but even 93 isn't enough under high temperature, high load and low RPM use. Even the "low Octane" table in the ECM can't pull enough timing under the wrong conditions.
91 Octane at one station doesn't always equal 91 Octane from another. Your best bet is to find the highest Octane at the highest volume Top Tier Brand station in your area and use it exclusively.
Part of the ECM function is to pull or add timing from various sensors such as air intake temp, coolant temp and etc. If any sensor falls on the wrong side of production tolerances you will get knock.
'Vettes are built to run best on at least 91 Octane but even 93 isn't enough under high temperature, high load and low RPM use. Even the "low Octane" table in the ECM can't pull enough timing under the wrong conditions.
91 Octane at one station doesn't always equal 91 Octane from another. Your best bet is to find the highest Octane at the highest volume Top Tier Brand station in your area and use it exclusively.
Part of the ECM function is to pull or add timing from various sensors such as air intake temp, coolant temp and etc. If any sensor falls on the wrong side of production tolerances you will get knock.
