I have a new Lexus RX200t which is now at 10k miles. I have been purchasing 98 octane gas but considering moving to 95. Is this recommended?
The manual says 95 is ok but I'd like to hear what experts think.
As Zaid said, if the manual says 95, use 95. Simple as that. Actually, using a higher octane rating is not ideal, whatever it may seem. From whatcouldbegreener.com:
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.
I might add, if your car pings using 95, the negative effects of using a higher octane are less than the negative effects of pinging.
If the manual says that 95 octane is suitable then the car will be fine with 95 octane.
98 will only yield appreciable performance gains if the ignition advance is being actively limited by engine knock. Since both engine and tune are set up by the manufacturer to handle 95, the impact of using 98 will be limited.