Scotty, what would happen if you use regular gas on a car that requires 91 octane like the lexus gs350?
Use the required gas by the manufacturer. You'll get the best performance out of the car.
Lower octane gas will increase the likelihood of engine knock in cars that require higher octane gas.
Knock is when the gas combusts prematurely, and lower octane gas tends to combust prematurely versus higher octane gas.
Modern cars have sensors which will adjust the engine to reduce knock, but you lose performance of your engine. But using lower octane in your case may even run horribly and potentially damage the engine. Unless absolutely necessary, use the recommended octane from the manufacturer.
what about using mid octane gas on premium required gas
Same idea. Use the octane that is recommended for your car. Nothing less unless absolutely necessary.
You can use higher octane on a car that requires lower octane with no adverse effects. But that’s just a waste of money.
The first thing you'll get is engine knock because the fuel isn't detonating properly. The more you drive it, the more damage you'll do until the engine goes.
what about when it says reccomended?
Then if you want the best MPG and power, use premium. If you want to cheap out and use regular, just know you will be down on power and not achieving the best possible MPG. BUT it SHOULDN'T hurt anything. If you hear knock, bump up to mid-grade. That is also in the owners manual for cars that recommend Premium.
If you use regular on a car that requires premium then you might have Engine Knock. Use premium if your car Requires it. If it says premium recommended then you should be OK with regular.
Modern cars will run on regular even if its supposed to on premium, just with lowered efficiency and performance. If it says premium required, just spend the money and get premium. The gas station you get it from also has an impact on your car's performance.
