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Hybrid TechnologyUnique topics related to the 2016 up RX450h model hybrid drivetrain and other features/options found only on the RX450h. Please use the main forum for discussion about shared components with other fourth generation RX models.
So you're able to use 89 octane to achieve this performance even though minimum recommended octane is 91? As an aside, I can't even find 91 octane at any of the branded gas stations in my area.
Don't know who this was for but I do use 89 and do not notice a difference. Like I said before, if you drive mostly on the highway the savings are not much. If you drive mostly in the city or traffic the savings are decent. There are many stretches in traffic where I'm mostly doing EV driving under 25.
I also use mostly Costco or Arco. I've tried Shell, Chevron etc but they're all the same IMHO.
Thank you for your input. But my point is that the savings in hybrid fuel economy would be offset by using premium fuel to achieve the desired performance. BTW, my Highlander gets a lousy 17 mpg city and 25 highway, which is why I'm so interested in the RX hybrid.
Trust me, you are going to get pretty much the same mileage with the RX350 as your Highlander. So even if you optimistically get 20 mpg combined (my 18mpg on the 350 was combined tank average, with maybe 30% highway); going by your calculations, your cost of fuel for the RX350 will be around $1,642 for regular; which would be more than the Hybrid on Premium (assuming you can maintain 30 mpg).
It's not just the monetary cost of the fuel savings. If you do drive 15k miles per year, the number of visits to the gas pump will drop by ~1/4; and that time should be factored into your cost as well.
And if you really want to save more money; you could always try 89 or 87 octane like a lot of people on here, and see if you notice the difference. 91 is only 'recommended' if you want the best performance. 87 is the actual minimum required (according to some versions of the manual), and the ECM can adjust for it.
I was drawn to Lexus for replacement of my 2008 Highlander Limited because I wanted a more luxurious vehicle which would get somewhat better gas mileage and help the environment at the same time. So I have been exploring the RX 450h (or RX 450hl). In fact, my wife has a 2020 Toyota RAV4 Limited Hybrid that she is happy with (40+ mpg), albeit the number of recalls that the car has had.
However, I’m very confused about the actual fuel savings between the RX 350 and RX 450h. Because the RX 450 requires premium gasoline, it would cost somewhat more at the pump.
Assuming that I drive a RX 450 15,000 miles per year, at an average of 30 mpg, and at $2.97 per gallon (for 93 octane at Exxon), the fuel cost would be $1,485. But for the same distance on the RX 350, which can run on 87 octane ($2.19 per gallon), at an average of 23 mpg, the annual cost would actually be lower, at $1,428.
I thought I was missing something. So I asked the dealer and the response was: 1. You can try 87 octane in the hybrid and see if you lose MPG after getting a baseline from a few tanks of premium. 2. Look at the other 3 benefits of the hybrid (less pollution, quieter, front brakes last longer). If in the end your math doesn’t make sense for the hybrid, please take advantage of an RX350 that uses 87 octane.
Thoughts, anyone? Please don't flame me if I appear to committing sacrilege.
I think the solid conclusion is you don't HAVE to use premium in your 450h. It will recognize a lower octane and adjust the timing accordingly. Regarding MPG, whether you benefit will likely depend on dozen different factors (where you live, weather, how you drive, etc.). In the end, you really just have to experiment and go with what works for you. Personally, I get about 1-2 MPG better with premium over regular. But others don't notice any difference. Unfortunately, with differences this small it really is going to "depend" as a 1 MPG difference is easily drowned out by larger impacts like traffic, weather, etc.
During the summer I can average a solid 30-32 mpg in my 450h. Drops to 28-29 in the winter, mostly due to winter gas.
Adding to what 1louder just stated, I live in Texas & in my area, it doesn’t get cold enough, so we don’t have winter fuel. However, my mpg will go down in the summer due to the high heat load from running the A/C. In other words, the engine doesn’t shut down as often in order to keep the A/C cold. I have never ever seen 30 mpg from the dealer driving it or my wife or myself driving.
Adding to what 1louder just stated, I live in Texas & in my area, it doesn’t get cold enough, so we don’t have winter fuel. However, my mpg will go down in the summer due to the high heat load from running the A/C. In other words, the engine doesn’t shut down as often in order to keep the A/C cold. I have never ever seen 30 mpg from the dealer driving it or my wife or myself driving.
Pretty sure I read somewhere that the A/C is driven by electric (not belt). So your engine may be running more due to having to run the alternator, not the A/C. I know that when I charge my 12V battery, the engine will shut off more often. You could try charging your battery to see if that helps.
Pretty sure I read somewhere that the A/C is driven by electric (not belt). So your engine may be running more due to having to run the alternator, not the A/C. I know that when I charge my 12V battery, the engine will shut off more often. You could try charging your battery to see if that helps.
I don't think the airconditioning drag is the issue, becasue as you said it is run off an electric motor. There is no alternator, but charging the main battery is off of the M1 motor, and of course if the batteries need charging the ICE will come on to drive M1.. You can especially see it happen in very slow moving traffic, where you might have a full charge and only be moving off the batteries, and then after being suck in traffic for along time, the ICE starts to recharge the batteries. Same thing happens with the airconditioner, where it will start out being driven by batteries, but if they get drained, then the ICE will come on. Having said all that, if you are driving normally, the M1 should be able to keep the batteries charged with no additional need for ICE.
I'm thinking of getting a 2022 RX hybrid. Dealer says it requires premium gas. Does anyone have experience using regular gas. I had a 2008 RX hybrid that ran fine on regular.
I'm thinking of getting a 2022 RX hybrid. Dealer says it requires premium gas. Does anyone have experience using regular gas. I had a 2008 RX hybrid that ran fine on regular.
I found what appears to be a 2022 RX owners manual here.
Page 454 says, "91 (Research Octane Number 96) or higher."
Page 461 goes on to say, "If the octane rating is less than 91, damage to the engine may occur and may void the warranty".
So this is stronger language than I've seen so far. My 2016 450h manual recommends 91, but says using lower is OK if that's all you have available. Many in this thread run regular. But to be honest I don't recall the language being that strong before. Wonder if this is a change with the 2022 model. octane rating is less than 91, damage to the engine may occur and may void the vehicle warranty
Same BS in my manual. I STILL USE REGULAR. Here is the quote from my manual. Lots of "mays" in the statement.
You must only use unleaded gasoline.
Select premium unleaded gasoline with an octane rating of 91 (Research
Octane Number 96) or higher required for optimum engine performance
and fuel economy.
If the octane rating is less than 91, damage to the engine may occur and may
void the vehicle warranty.
At minimum, the gasoline you use should meet the specifications of ASTM
D4814 in the U.S.A.
Sounds like the lawyers talking. ANY modern ICE can automatically adjust to the octane. However, the official performance specs were derived with the recommended octane. I'd expect a very slight reduction in power on regular.
Or it could possibly be that if the knock sensor were to fail then the engine timing would be too advanced for regular and you'd get knocking. Over a long period of time that could lead to engine damage. That said, I've never heard of a modern engine destroyed by using regular.
And, yes, I also run Costco regular, as we have in our other cars over the years. No issues.
Page 454 says, "91 (Research Octane Number 96) or higher."
Page 461 goes on to say, "If the octane rating is less than 91, damage to the engine may occur and may void the warranty".
So this is stronger language than I've seen so far. My 2016 450h manual recommends 91, but says using lower is OK if that's all you have available. Many in this thread run regular. But to be honest I don't recall the language being that strong before. Wonder if this is a change with the 2022 model. octane rating is less than 91, damage to the engine may occur and may void the vehicle warranty
Same wording in the 2021 version too. No option for plus or regular. I do know that for engine damage, they will take a sample of the gas to measure the octane, so those of us with later models where "premium only" replaced "recommended" be aware. I asked the Car Care Nut specifically why the 3.5L in the 450H/350 needs premium 91-93 and the same engine in the Highlander uses 87. He said it was due to the tuning in the Lexus. Here is the episode, and the question was asked and answered in the chat.
Here are the results of the four cars they tested. Note what is minimum vs. recommended.
Also a good summary on knocking:
Your car doesn't know the octane rating of the fuel in its tank. Instead, the engine controller calculates an inferred octane with closed-loop logic that continuously advances the ignition timing until it detects knock, which occurs when a portion of the fuel-air mixture ignites before the spark-plug-initiated flame front reaches it. The further the computer can advance the timing without provoking knock, the higher the octane rating.
During knock, the flame front travels through the combustion chamber up to 10 times quicker than the normal spark-initiated flame front. Left unchecked, these pressure waves can damage the head gasket, pistons, or cylinder head. But the occasional brief knock is a useful tool for checking that the engine is operating efficiently. It's detected with one or more knock sensors bolted to the block to sense the oscillations created by the pressure waves with a typical frequency between 7 and 16 kilohertz. Stephen Russ, senior technical leader for gas engines at Ford, says this normal knock is usually detected and addressed within one or two combustion cycles and poses no threat to the engine.
12-21-20, 07:53 AM
