In a nut shell as long as it don't ping your perfectly fine.
Most newer engines will not ping today unless you get bad gas or they have an issue like bad sensor or carbon build up because the computer compensates everything today. Wife has owned a 2000 Infiniti since new with 10:1 compression so we ran the 91 octane thats "Recommended" for years until I learned as long as we only get gas from Top Tier gas stations (see link for info/list) then it makes no difference on the grade anymore and we've ran the lowest for many yrs now. Our MPG remains the same regardless too.
But' If we buy low grade from Non Top Tier fuel stations like many convenient stores sell not only will it ping it will throw a light right off the bat too, I guess thats "Pong"?..lol
One day I filled it up at a convenience store and only drove a mile or so away and it threw a light that fast. Thats when I first learned about Top Tier gas and whats been going on for years between our gov, gas corps and car makers. Learning all about Top Tier fuel was an eye opener for me.
The fact is the key words are "
Recommended" vs "Required" that are used by your car maker but' the key problem here is "Ping" aka Spark Knock.
If it pings a little bit off/on (NOT CONSTANT PING) no damage occurs. In fact old drag racers will tell you that intermittent ping tells them timing was set perfectly, its maxed.
Turn distributor till the engine pings/drag starts then back it up a ticks turd, your sweet spots right there. We always ran them like that because you couldn't use a timing light on our race cams so thats what we all did on street or strip, muscle cars. Just a note there:
But' todays computer cars adjust timing/air/fuel etc for you so today pinging can mean bad gas, a sensors going bad or carbon buildup so if pinging is constant or engine still pings after two tanks of Top Tier High Octane fuel keep that in mind. Failing sensors are known for causing it with/without throwing a light.
Again, Higher Octane fuel is either "
Recommended"
or "
Required" with higher compression engines and worrying about pinging started from older cars without sensors/computers that didn't compensate to stop ping like all newer cars do now.
My 1969 Super Bee I drove as my daily till 2012 with 425+hp & 13:1 compression with full race cam would ping intermittently on 87 grade but never ping on mid 89 grade using Sunoco/Shell gas only. I never ran the highest grade with their fuels, but I always had to run 91+with other stations including Marathon. People saying it makes no difference where you buy your gas at are dead wrong, its not all the same fuel mix unless some really shady chits happening in your area. Some cars actually tell you who has the bad fuel around town if you only listen closely, but octane levels rarely matter on new engines now days, super cars, race engines mainly do
Require it. Most only
Recommended it!
See links-
Good write up on octane fuels here..
https://www.hemmings.com/stories/20...-the-fiction-behind-those-higher-priced-fuels
All about better Top Tier fuels here...
https://www.toptiergas.com/why_top_tier/