Interesting thanks. Do you know if your recommendation applies to a 2006 Buick Lucerne?
I’ve been told it’s designed for 93 octane but the computer will adjust for lower octane levels just as you said. But I didn’t hear about this savings being offset by higher fuel usage but what you say makes sense.
If I should go to the higher octane will I see an immediate rise in my fuel economy or will it take a while for the difference to become noticeable?
Thanks in advance for any help you can offer.
If you have the 3.8L V6 the compression ration is advertised at 9.4:1.
I’d say this engine needs 93.
If you run the tank down and refill with 93 you should start to see improved mpg. Then after the next fill up you’ll probably be looking at your steady state mpg with 93. With a little math you can figure out if any increase in mpg is worth the increase in cost per gallon.