Premium fuel required on the RX350?
06-28-24, 11:58 AM
#106
Cars with ECU controlled ignitions and timing don't knock anymore, so the lack of a sound means nothing. Check your MPG against premium, it will surely be lower. And the RX350 MPG is pretty low to begin with.
06-28-24, 12:00 PM
#107
Intermediate
I've been using regular octane gas (87) on RX350 for a couple months now. So far didn't feel any difference from 93 octane gas. No engine knock, no loss of power, no matter if it's 30-degree or 90-degree day, car runs the same, even did multiple wide-open-throttle pulls, no knocking.
This is to test on the claim in this link that our engine is the same as the ones in the new Highlander, and they can use 87.
So, go ahead and try it if you don't want to be ripped off by premium gas
(of course do it at your own risk and I'm not responsible for any loss or damage to your vehicle 
)
This is to test on the claim in this link that our engine is the same as the ones in the new Highlander, and they can use 87.
So, go ahead and try it if you don't want to be ripped off by premium gas
(of course do it at your own risk and I'm not responsible for any loss or damage to your vehicle )
06-28-24, 12:01 PM
#108
06-29-24, 07:05 AM
#109
Pole Position
Use regular octane gas in over 10 vehicles that either required or recommended premium. Never noticed any difference in acceleration nor miles per gallon. Driven over a million miles never had an engine problem. Don't believe me go to YouTube and put in CBC gasoline octane and watch the video where they test different grades of gasoline. Much more important is to use a top tier brand.
Last edited by Freds430; 06-29-24 at 07:21 AM.
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06-29-24, 09:45 PM
#110
I doubt that it has more compression, but I believe that the ignition map is optimized for higher octane.
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Carbuff2 (06-30-24)
07-01-24, 08:15 AM
#111
I am still confused whether or not the RX 350 requires premium gas. My vehicle is being built this week and so the only owners manual I have been reading is on line it states premium is required. As a senior citizen I am not into jack rabbit starts and most of my driving is local, so I wouldn’t be pushing the envelope.
07-01-24, 08:18 AM
#112
I have an RX350 pure gas since Sept2023 and I only used 87-octane gas and it's running fine. From my experience, if your car is required to use ONLY premium gas (92-octane or higher), your gas fill hole will NOT accept the 87-octane receptacle, it will only accept the smaller receptacle, which is the 92-octane or higher.
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07-02-24, 08:08 AM
#113
Intermediate
I wonder if that's a California Rule (the gas filler neck being different sized) , because it sure isn't in Wisconsin.
07-02-24, 08:13 AM
#114
I'm in California. 87 and 91 fillers are the same size. I've not heard of different sized fillers for automotive gasoline since the days of leaded gas.
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07-03-24, 04:20 AM
#115
Intermediate
yup, they're the same size because they're precisely the same nozzle around here, i.e. you just press a button to choose your octane level. Been that way for a loooooong time.
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BLUKTY2 (07-04-24)
07-03-24, 04:21 AM
#116
Intermediate
07-03-24, 04:36 AM
#117
THAT is the point. To differentiate between the Lexus and Toyota brands.
I think that modern-day engine controls can compensate for variations in octane easily, without incurring damage. We seldom ask for maximum power in our largely suburban driving.
++++++++++++
Would drivers notice the difference 87 VS 93 in everyday driving? Prob not.
We have used 87 in our 500h the past two tanks (because we also needed to fill up our lawnmower & generator fuel cans, and Costco is SO busy...don't want to anger the folks in the line behind us). No difference that I can tell, either in running or in fuel economy.
But we WILL go back to 93 octane next fill.
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BLUKTY2 (07-04-24)
07-03-24, 06:48 AM
#118
Pole Position
A retired Acura engineer was quoted as saying we said premium in many of our models because it made the owners feel like they were buying something special. Car Talk a great show, The tappet Brothers said there's no reason unless you have a high supercharged engine that you would ever need medium or premium grade. Again go to YouTube and search CBC octane grade gasoline. They did a study and it showed exactly that.
07-03-24, 10:08 AM
#119
Intermediate
As a premium brand, Lexus 'tunes' its engines for the extra power that higher octane provides. They advertise the additional power as well.
THAT is the point. To differentiate between the Lexus and Toyota brands.
I think that modern-day engine controls can compensate for variations in octane easily, without incurring damage. We seldom ask for maximum power in our largely suburban driving.
++++++++++++
Would drivers notice the difference 87 VS 93 in everyday driving? Prob not.
We have used 87 in our 500h the past two tanks (because we also needed to fill up our lawnmower & generator fuel cans, and Costco is SO busy...don't want to anger the folks in the line behind us). No difference that I can tell, either in running or in fuel economy.
But we WILL go back to 93 octane next fill.
THAT is the point. To differentiate between the Lexus and Toyota brands.
I think that modern-day engine controls can compensate for variations in octane easily, without incurring damage. We seldom ask for maximum power in our largely suburban driving.
++++++++++++
Would drivers notice the difference 87 VS 93 in everyday driving? Prob not.
We have used 87 in our 500h the past two tanks (because we also needed to fill up our lawnmower & generator fuel cans, and Costco is SO busy...don't want to anger the folks in the line behind us). No difference that I can tell, either in running or in fuel economy.
But we WILL go back to 93 octane next fill.
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WellsB (07-03-24)
07-06-24, 03:48 AM
#120
When picking up my new car purchase (2024 RX350H Premium+) the gas tank was 1/4 full. I went on the test drive and filled the gas tank with premium 93 which the dealer paid as part of delivery of a new vehicle. I asked my Lexus Technology Specialist and Sales Rep if it needed 93 premium gas and he said it’s NOT REQUIRED but RECOMMENDED per the owner's manual. They said typically it’s filled up with regular 87 gas for the 2024 RX350H hybrid models.
Premium 93 gas is better for your car if you tend to keep cars long. 7+ years.
Premium 93 gas is better for your car if you tend to keep cars long. 7+ years.
Last edited by AznD85; 07-06-24 at 04:32 AM.