What fuel grade are you using in your RX350?
#301
The VVT-iW can effectively reduce the compression ratio, a quasi-Atkinson cycle effect. If the ECU can control the VVT-iW and the ignition timing simultaneously, not to mention the fuel-air ratio via the EFI, then you have a range of compression and ignition combinations to dynamically adapt to the actual ignition behavior of the engine with whatever fuel it is using.
Last edited by dibl; 07-25-21 at 02:09 PM.
#302
The VVT-iW can effectively reduce the compression ration, a quasi-Atkinson cycle effect. If the ECU can control the VVT-iW and the ignition timing simultaneously, not to mention the fuel-air ratio via the EFI, then you have a range of compression and ignition combinations to dynamically adapt to the actual ignition behavior of the engine with whatever fuel it is using.
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raylor4 (07-27-21)
#305
Exactly correct. I did that, and changed out the oil at 1000 miles. I don't go for the 10k miles changes. My normal day has at least 6 starts and stops of the engine, and not a lot of miles traveled, so it's hard on the oil and I change it at 5k miles.
#306
Hey guys,
Just got a RX350 2021 with 4 miles in the ODO last week. I've been searching about the performance difference of using regular gas or premium gas. I do not care about the price per performance, or anything related to price. All I want to know is, does using premium improve the performance of the car? I have a MDX 2020 that takes premium. The manual on that car says Minimum 87, Recommended 91. The difference in acceleration is noticeable. The RX350 2021 manual just says "87 or higher". The compression ratio of the engine used in the MDX 2020 and RX350 are almost identical, 11.5 (MDX) vs 11.8 (RX350). This is why I am wondering if the gas makes any difference in this car. Thanks!
Just got a RX350 2021 with 4 miles in the ODO last week. I've been searching about the performance difference of using regular gas or premium gas. I do not care about the price per performance, or anything related to price. All I want to know is, does using premium improve the performance of the car? I have a MDX 2020 that takes premium. The manual on that car says Minimum 87, Recommended 91. The difference in acceleration is noticeable. The RX350 2021 manual just says "87 or higher". The compression ratio of the engine used in the MDX 2020 and RX350 are almost identical, 11.5 (MDX) vs 11.8 (RX350). This is why I am wondering if the gas makes any difference in this car. Thanks!
Very bottom line, the dyno results showed small drops in hp (like 1-5) using lower octane fuel in a car that recommends higher. None of the drivers said they could feel any difference in "butt feel" driving the car. So there is likely a small difference, but maybe not one that you may notice. My recommendation would be to try a tank on each and see what you conclude. Each of the cars C&D tested had slightly different results.
MPG results varied too, some getting 1-2 MPG lower with the lower than recommended Octane. But some cars did equally well.
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ravenuer (07-26-21)
#307
I'm on my third fill, using Costco 93 (they only have 87 and 93, 20 cents difference). The acceleration is much better imo. The first thing I noticed about this car initially was that the acceleration was bad, very bad compared to my Acura MDX 2020. Now, It has improved a lot with the premium gas, but still not close to my MDX 2020. I will just keep filling the car with 93 octane just for the performance. Alternating between both cars, I can appreciate the pros and cons of both the Lexus and Acura.
#308
#309
I'm on my third fill, using Costco 93 (they only have 87 and 93, 20 cents difference). The acceleration is much better imo. The first thing I noticed about this car initially was that the acceleration was bad, very bad compared to my Acura MDX 2020. Now, It has improved a lot with the premium gas, but still not close to my MDX 2020. I will just keep filling the car with 93 octane just for the performance. Alternating between both cars, I can appreciate the pros and cons of both the Lexus and Acura.
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Quantum501 (08-01-21),
ravenuer (08-01-21)
#310
Might be the placebo effect. Have a friend fill your empty tank with either 87 or 93 without telling you which and drive until empty. Then have that person fill your next tank with the other fuel grade and drive until empty. After driving both tanks compare your blinded experience with your friend's fuel details.
#311
Yikes -- please don't do that, or even close to it! You'll burn up the fuel pump! Even with a gallon or two, when you turn a corner it all sloshes to one side, potentially exposing the fuel pump to loss of cooling (and your wallet to a major leak ...).
Double-blind experiments are fine, when feasible. But objective data can be obtained from the odometer, the numbers on the gas pump, and a calculator, as I posted above.
Double-blind experiments are fine, when feasible. But objective data can be obtained from the odometer, the numbers on the gas pump, and a calculator, as I posted above.
Last edited by dibl; 08-01-21 at 10:20 AM.
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#314
Might be the placebo effect. Have a friend fill your empty tank with either 87 or 93 without telling you which and drive until empty. Then have that person fill your next tank with the other fuel grade and drive until empty. After driving both tanks compare your blinded experience with your friend's fuel details.
In any case, you might well find some minor differences in both power and fuel efficiency, depending on the fuel grade, but those differences should be minor, and using the lower octane grade will not harm the engine.
#315