I was just watching a review of the 2021 Mazda3 turbo, the tester stated he couldn't get the car to do the advertised 0-60 time of 6 seconds, then he stated that the car probably not been refilled with premium fuel and that would cut the power by 40hp. How does the car know if it's got premium in it? does it just go off the knock sensors and it retards the timing till it stops?
Oh it goes by the knock sensors but also the air fuel ratio sensors and lots of stuff the computer programs are pretty sophisticated these days
The ability to reduce engine power to adapt to different octane ratings has been around a real long time. As Scotty says the engine management system will detect the onset of detonation and dial ignition timing etc. back to compensate. My car is 24 years old and does it - makes the most power with premium gas but it won't complain if you put regular in it, just makes less power.
I saw a video the other day where a V12 Mercedes AMG developed BAD drivability problems after a fill up with "premium" gas. The presenter said he thought it was partially because in the winter all the sports/high end cars were in garages, and that premium was very slow selling and thus contaminated.
https://www.youtube.com/watch?v=fCuMb330bfo
