Re: 91 and 93 octane
What I stated is correct. It's documented. It's what I believe, anyway.
What will happen if I use higher octane gas than I’m supposed to?
A few things. For one, you will be wasting a huge amount of money paying for high octane gasoline. Second, your car will not run correctly, whether you notice it or not. Higher octane fuel requires more heat and more precision to burn correctly. If your car is designed to burn 87, it will not burn 93 correctly. Third, your gas mileage will suffer. The inability of your engine to burn the higher octane gas correctly will cause your engine to produce less power and thus will require more fuel to perform at the same level
For most cars the answer is NO. Higher octane fuels burn slower so unless you can increase your initial advance you will not see any difference. Also when a vehicle is tuned to use lower octane fuel a higher octane will create carbon deposits and over time will cause engine ware, overheating, and poorer fuel economy. Todays igitions are computer controled many are distributorless so we shade tree mechanics can't mess with them. Many of todays vehicles recommend 91 octane but can use 89 or 87 if you don't hot rod them or over load them, more than two people.
'97 3.8L V6
1996 SVT Cobra White