Regular or Premium?
Thread Starter
3rd Gear
Joined: Apr 2025
Posts: 3
Likes: 0
Regular or Premium?
So I'm in the process of buying this 2010 RX 450H, and searching online I've seen people using both regular gas, and premium. What do you use? And what does Lexus recommend for this vehicle? Thanks!
Driver
Joined: Jan 2024
Posts: 60
Likes: 7
From: Delaware
I know I'm late to this party, but I've tested regular & premium in my 2012 450h, same gas mileage with both, and I don't *notice* any difference in acceleration, when I jump on the loud pedal, both electric motors -front & rear- cut in and she does very very well. OTOH, if I were heavy on the gas pedal I'd be killing the gas mileage, and I bought the hybrid version to avoid the 15mpg city, 25mpg highway mileage. It's absolutely true that the car will retard the timing to keep motor from pinging due to lower octane gas. This *will* cause a loss in horsepower. In my old 2007 es350, the 3.5 L V6 was rated at about 279 horsepower, tested using premium gas. OTOH, my old 2005 Avalon (3.5 L V6) was rated at about 274 horsepower, tested using regular gas. The engines in both cars were identical, the difference in rated horsepower was due to gasoline used. I never suffered any engine repairs in either vehicle. The roughly $0.75 to $1.00 difference per gallon helps make the decision on premium -v- regular an easy one.
Pit Crew
Joined: Jun 2003
Posts: 170
Likes: 6
From: Florida
Premium required for sure
I tried using Regular Gasoline since purchasing my 2011 RX450h in 2015 and I definitely noticed a difference in performance, but I had to stop using 87 Octane gas in my vehicle because it ended up triggering my check engine light and a faulty 02 sensor error code after eight years of using 87 Octane gas. I actually used 4 tanks of regular gas followed by one tank of 91 octane gas during this time. Since I received the 02 sensor error code I have used 91 Octane gas exclusively for the past two years without any additional issues.
Intermediate
Joined: Jan 2018
Posts: 360
Likes: 42
From: Victoria, Australia
One summer, I was driving along a long uphill road, and I had my windows down. Alongside the road was a rather long brick wall, and to my horror, I could hear the engine pinging faintly due to the sound reflecting back from the wall. This was with regular (low octane) unleaded.
With the windows up, I couldn't hear it but it was definitely there because I doubled back and re listened just to be sure.
I switched back to a mid grade octane fuel later in the week and drove around for a few days to get the new fuel into the system. Then I tried the same listening test on that same road, once again listening to the sound of the engine reflecting off that wall with the windows open.
Lo and behold the pinging noise wasn't there anymore. Ever since that day, I only put mid grade or E10 fuel into the vehicle, which has higher octane than the regular unleaded.
With the windows up, I couldn't hear it but it was definitely there because I doubled back and re listened just to be sure.
I switched back to a mid grade octane fuel later in the week and drove around for a few days to get the new fuel into the system. Then I tried the same listening test on that same road, once again listening to the sound of the engine reflecting off that wall with the windows open.
Lo and behold the pinging noise wasn't there anymore. Ever since that day, I only put mid grade or E10 fuel into the vehicle, which has higher octane than the regular unleaded.
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