Actually, most, if not all, vehicles for the last few decades have knock sensors and retard the timing if preignition is sensed. On my '03 Sentra Spec-V it was a big deal because the knock sensor was overly sensitive and would rob the engine of power even with 93 octane. When I had an '11 Camaro SS, a common issue on the forums was from dealers that put in regular fuel before delivery, causing knock and retarded timing, and the computer wouldn't switch back until you removed a couple fuses overnight.
Yup!Actually, most, if not all, vehicles for the last few decades have knock sensors and retard the timing if preignition is sensed. On my '03 Sentra Spec-V it was a big deal because the knock sensor was overly sensitive and would rob the engine of power even with 93 octane. When I had an '11 Camaro SS, a common issue on the forums was from dealers that put in regular fuel before delivery, causing knock and retarded timing, and the computer wouldn't switch back until you removed a couple fuses overnight.
The other important thing to note is that if you run 87, the engine will sense the knock and retard the timing so it goes away, however, preignition has already occurred which is not good for engines.
My simple answer is that I always run what the manual says to run. Most vehicles I've had did not call for premium, so I ran regular. But if it says premium, or premium is best for performance, then I run premium.
Not sure you can quantify the difference with the seat of your pants n pedal on a stock setup.
i run e85 instead seems to run better then 104 octane i was running
