Does the lexus RX 450h require premium unleaded? I have an ES-350 now and use regular

http://www.edmunds.com/lexus/rx-450h/2010/features-specs.html? style=101162469 -- this states premium required.

My lexus rx400h does not require premium. If you use regular you might get 1/2 to a mile per gallon less . You would not notice any difference in performance or hurt your engine.I heard that you can have your timing retard, but I am not sure that it makes any difference. Did you notice that the gas stations have quietly conspired and raised the price of premium by 40 cents a gallon? I did not in the begining.. They always challenge your intelligence and observation capacity.

The owners manual for the 2016 RX450h states premium gas should be use. The manual for the 2016 RX350 states regular gas should be used. Both models have the same engine. I've been driving my 2016 RX450h for nearly a year, using regular gas. It runs great! I've experienced no problems at all with performance or gas mileage. I see no reason to pay 40 cents a gallon more for premium gas.

The engines for the RX350 and the RX450h are similar but not the same, as the 450h engine runs a modified "Atkinson" cycle. Lexus literature recommends premium for the 450h, but I wouldn't be surprised if it ran reasonably well on lower octane fuel, given that most engines will adjust timing automatically to avoid pinging. We've recently purchased our first tank of fuel for our 450h, and spent the extra 20c/g to follow the manufacturer's recommendation; as I recall the owner's manual states it as a recommendation rather than a requirement. With all the automation in the car, the engine computer can probably record information that would tell a dealer what fuel is being used, what a dealer might do with that information is not knowable.

I have owned 3 Lexus hybrids over the past 10 years - one 400h and two 450h. I have driven each of them over 50k miles using regular unleaded with zero problems.

Can u tell me how much it effected the gas milage off the 30 mpg estimated...

The 30 mpg rating is determined with the vehicle running on a treadmill type device, on a level surface, indoors (with no wind interference). You will get nowhere near 30 mpg driving in real-life conditions. I live in a very hilly area. I ran 2 tanks of premium gas in my 2016 RX450h, in both economy and standard modes; the best gas mileage I got was 24 mpg. That rating was the same when using regular unleaded fuel.

For 2019 models: The compression ratio of RX450h is 13 (Fuel Type: Premium Unleaded), RX350 is 11.8 (Fuel Type: Unleaded), and Highlander Hybrid is 12.5 (Fuel Type: Unleaded). They all used the same gas engine. What is a compression ratio? The compression ratio is the ratio of the volume of the cylinder and the combustion chamber when the piston is at the bottom, and the volume of the combustion chamber when the piston is at the top. Diesel engines have no spark plug. They need high compression ratios to generate the high temperatures required for fuel auto ignition. Compression is much higher with a diesel engine (14:1 to 25:1). RX450h compression ratio is 13 very close to the lower end of a diesel engine compression of 14.1. If regular unleaded is used with higher compression engine similar to RX450h, it might ignite prematurely far before reaching near the top dead center of combustion chamber that can cause the engine to knock. The piston and connecting rod assembly including the crankshaft will be subjected to tremendous stress when this happens. Premium unleaded Octane Number is 91-94 while regular Unleaded is only 87. What is an Octane number or rating? An octane rating, or octane number, is a standard measure of the performance of an engine or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating. I believe that using regular unleaded for RX450h in the long run will damage the engine and will cost a lot to repair. It might take years before the symptoms show.

I have a 2011 Lexus RX 450h with 165,000 miles. Starting about 5 years ago, I switched from premium (93 octane) to mid-range or "Plus" gas (89 octane). So far, there has been no knocking or noticeable deterioration in performance. The comment above from Procotoy warns that it might take ten years to notice any damage. For what it is worth, my 2013 BMW 740i manual recommends mid-range gas for that engine. I have not compared the compression ratios of the two engines, but now I may try to determine if there is a difference that justifies the recommended gas difference.

I have a 2010 Lexus RX 450h AWD version that I bought used in 2012. I find it doesn't run well on regular gas (especially on the expressway), but middle-test does fine. It doesn't get quite the gas mileage on middle-test gas, maybe about 2 miles/gallon less than when using high-test, but I've been using middle-test for years, given the price of high-test gas. Hope this helps.

Doesn’t the few gallons lost say compounded by 2 mpg less average mean saving a buck is actually pointless, damaging and will be costly. So a 2021 Lexus 450h with a 13 gallon gas tank would lose 26 miles in range average per fill up about the same really world mpg rating. So about a gallon lost per trip at the possible cost of the engine and the price lost in mpg kind of negates the cost of saving (40 cent extra per gallon x 13 gallons = $5.20 extra paying premium per fill up - $4.00 lowest cost of premium is SF). Literally risking the health of your vehicle and being a cheap skate over $1.20 per fill up!?!? It’s a higher octane, it’s a more controlled burn, regular might work for a Toyota Highlander or a smaller 350, but I’m not going to take a chance on my $60k+ 450h. You’re driving a moving living room worth anywhere from $40-$120k depending on the year and model, but you’ll cheap out on around $1.20 per fill up. Drivers that do things like this to cheap out with no research are never the proud ones to post of there failures when things actually do go wrong. And when it happens it will be expensive, and Lexus will know what fuel type you used to destroy the engine to void any warranty you might of had.

I agree with John. I bought my 2nd 450h in December and will not use anything but premium until the warranty expires and then I will decide. . If your willing to spend 60k for this car spending 5 dollars a fill less seems a bit crazy at least while the car is under warranty . My 2011 450h was run on premium for the first 90000 miles and run another 100000 on a mix regular or mid grade with no problems

About to buy a 350 or 450h. If you do the math, comparing the extra money you pay for premium gas versus running regular in a RX 350, the cost for 10,000 miles cost is about the same. So you think you are getting great mileage but it's not saving money. Hmmmm. So I talked to a guy who has had a 450h for years and he said the cost was about the same. He had hoped it would be better but it was not.

Guru9CCGV4 brake maintenance will be cheaper on hybrid :)

I have a 2008 Lexus rx400h with about 135,000 miles on it. Filled it up with premium on my first tank and used regular after that. Never had any knocking or engine issues. Car runs great and I am about to buy a 2022 rx450h. Maybe I’ll put premium in on my first fill up but not after that.

@@@For 2019 models: The compression ratio of RX450h is 13 (Fuel Type: Premium Unleaded), RX350 is 11.8 (Fuel Type: Unleaded), and Highlander Hybrid is 12.5 (Fuel Type: Unleaded). They all used the same gas engine. What is a compression ratio? The compression ratio is the ratio of the volume of the cylinder and the combustion chamber when the piston is at the bottom, and the volume of the combustion chamber when the piston is at the top. Diesel engines have no spark plug. They need high compression ratios to generate the high temperatures required for fuel auto ignition. Compression is much higher with a diesel engine (14:1 to 25:1). RX450h compression ratio is 13 very close to the lower end of a diesel engine compression of 14.1. If regular unleaded is used with higher compression engine similar to RX450h, it might ignite prematurely far before reaching near the top dead center of combustion chamber that can cause the engine to knock. The piston and connecting rod assembly including the crankshaft will be subjected to tremendous stress when this happens. Premium unleaded Octane Number is 91-94 while regular Unleaded is only 87. What is an Octane number or rating? An octane rating, or octane number, is a standard measure of the performance of an engine or aviation fuel. The higher the octane number, the more compression the fuel can withstand before detonating. I believe that using regular unleaded for RX450h in the long run will damage the engine and will cost a lot to repair. It might take years before the symptoms show.@@@ All of the above is complete bullshit. 1) Let's start with the fact that the 3 cars presented in the example have ABSOLUTELY different engines - Rx 350 2GR-FE - Rx 450h 2GR-FXE (absolutely different from FE) - Highlander 2021 even 2.5l and compression = 14!!!! and it's still required REGULAR!!! - Venza 2021 compression ratio = 14, still required REGULAR!!! - Prius also has a compression ratio of 13, but the Prius can still use regular gasoline to this day. why all these cars don't require 91 gasoline??? Just for expirement i'm using regular now and still have 29 on highway and 30+ in city. my opinion is that these requirements are nothing more than a marketing move to emphasize the status of the car.