I use 94 octane here at Petro Canada only cause it makes me fell like this >>

 

gm recomennds that no aditives be used. they do recomend Mobil 1 oil. i believe in some additives , i plan on adding ZMAX. i've always been "a ford person" , so if Carrol Shelby says it's good , i believe it , he has too much $ and reputation , to be a sell out.

 

Man...what you don't know about Shelby.

And...you don't need ZMAX or any other oil additive. Mobil 1 is an excellent choice--just use the 10W30 rather than the 5W30.

 

Hay Hib, Are you an x Flt. engineer?

 

I do agree that there is no additive that I would put in my oil.

Hib, why do you reccomend the heavier oil? The thinner oil gets better mileage and is reccommended by Chevy. The Ecotec motors are designed with tight tolerances for the thinner oil. I would never use it in an older motor though. I always use the Mobil 1, I do believe it is better than traditional oil.

 

If the octane is too low then the knock sensor kicks in retarding ignition and possibly adding fuel. Performance and mileage goes down. Now if there is no knock then there is no performance or mileage to be gained by using the higher octane. Your performance and mileage could be down 10% or so and you would never know it becuase the ECM is compensating for the knocking.
I do not know of anyway to tell if the car is running full advance or retarding ignition for the fuel?

Also I think the ECM averages your driving style so it may take a while for your car to see any increase in mileage or performance with a fuel change.
To get a true test you should probably reset your ECM.

 

First, there are two ignition tables, High and Low Octane. If the knock sensors sense knock, the ECM will immediately retard timing to eliminate knock. Then, the ECM will calculate the "Knock Learn Factor", which will basically (to the uninformed) "average down" between the two tables.

Despite the above post, NO fuel is added to compensate.

There is a way to tell how the ECM is compensating, via the Knock Learn Factor, easily seen with HPTuners.

The Knock Learn Factor will shift up or down due to the fuel used and other conditions.

The ECM doesn't do sh*t about your "driving style".

Reseting the ECM only resets fuel trims and the KNF. They will quickly relearn.

Bottom line... If you don't understand, PLEASE don't speculate!!

 

First of all I've always valued your comments, but....What's wrong with a little speculation?

We all come on to this forum to learn. But if we don't speculate or voice our ideas in places like this forum, how do we know if we are wrong or right? This is the place to do it so that someone like yourself "Mr. No Bull" is there who might know better to give us the 411.

GEEZE I gotta get a life

Daryl/GRUMPEE

 

Driving style or "Knock Learn Factor" Whats the difference? The car computer is compensating to eliminate the knock under the load. So I used the wrong wording.

And if resetting the ECM resets fuel trims then for the original post it migt be the only way to really tell if there is any difference between the octane.

Geez, Bite my head off. You have a nice day there Buddy.

 

i did not reset my ecm , when i did my 60+ gallon test. so , does this mean that my results were not valid??? wouldn't that be enough time / miles / fuel , for the ecm to relearn???