Quote:
Originally Posted by hav0c
I'm not as concerned with performance as avoiding any kind of knock and forcing the ECU to relearn the 91/'low octane' thats being used on a regular basis.
|
One aspect of modern vehicles that you will have to accept, all modern engines knock ,especially at low load high timing and AFR. What you have to be concerned with is knock that is consistent, and happening during high load, open loop operation. To a certain extent the the engine will correct the reason for the knock (either retarding ignition timing, increasing fueling, or a combination of the two). If the manufacturer did not want the vehicle to be run with 91 octane than it would not be sold in your state with a warranty. I live in New Mexico, and our gas is as bad as yours, interesting as we are so close to Texas... I degress. Anyways, your vehicle will not be at it's most efficient running 91 octane, only you can decide if the extra $5.00 to $8.00 is worth spending every time you fill up.
And also Rice, yes ALL OBD II ECU's have a octane parameter built into the factory ECU system, whether it is determine proper ignition, fueling, or different alpha N calculations (Honda) for the cylinder events. Yes different automobile manufacturers have different ways of dealing with knock, but ALL have a sub routine to change the octane count on the fuel once it is detected.