87 octane vs 89 octane

[razor02097]

Originally Posted by redpoint5

I have an UG and have it setup to show the timing advance. How do I know if it's at full advance?



There is zero chance that going faster, regardless of octane, results in better fuel economy unless your truck shifts to a lower gear between 95kph and 105kph.

Full advance numbers can be found in most FSM. Typically full advance occurs under cruising speed (45-55mph) Usually 30-40* timing maybe more (big range because there are many different engines). If there is detonation going on the ECU will pull timing so you will see the numbers change drastically when it senses knock. There are also data logging software that can tell you "counts" of knock which means when the knock sensor thinks it hears knock it adds to the count.

[gone-ot]

...logging the Knock Sensor count also lets you know whether your engine wants/needs 91 octane gasoline or OEM-specified 87 octane.