Lol, 381 is enough.

I think that's all it really boils down to, honestly. If you put premium in a Tundra then you'd have 383.

Hate to sound so cheap but premium is like 60-80 cents more....that times 25 gallons.....would add up over time.

 

You can look at this thread. It was discussed many times here and also on ih8mud.com
https://www.clublexus.com/forums/lx-...m-premium.html

 

Thanks. There is no way I'm wasting money buying premium fuel just because it's a Lexus.

If you filled up every week I'd say you'd save 60-70 bucks a month. That would knock out one of my utilities at my house.

I'm not cheap but I refuse to waste money, regardless of what it is.

 

Personally the difference (in terms of cost) b/w Reg vs Prem gas is about 30cents a gallon, I never wait till the very last before filling up (better fore the fuel pump), so each time I fill about 16 gallons or so...with a diff of 30cents b/w Reg and Prem fuel, that's about $5 diff each time. I fill up about 2x each week, so 8x / month on average, so $40 extra per month...$500 or so annually. It's my daily driving vehicle.. looks pretty bad when driving next to an electric car or a hybrid... but I knew before I pull the trigger to buy this car, its gas mileage isn't going to be great, if I want to save of gas I would no have bought this LX. For me a savings of $500 annually isn't that big of a concern, there are so many other ways to cut down to fund my LX.

 

My 2018 Lexus owner's manual page 566 clearly states to use octane rating of 91. Any thing less than that might damage the engine & void the warranty.


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Here we go...I need emoji's for popcorn and beer, but none here.

IF you really believe that, make sure when you do the routine transfer case oil change to use ONLY Toyota 75W oil...~ $80/l, and you'll need two bottles.

I'd also ask if you seriously trust "lifetime" transmission fluid.

You're driving the cushy version of the Land Cruiser...it requires 89 octane. Both engines are made at the SAME plant in Japan, with the same 100% Japanese parts content. OT, but not the same as 5.7's for the Tundra and Sequoia, which may be assembled in the US and no guarantee of 100% Japanese parts.. The LX uses the same knock sensors as the Cruiser. HP differences between the two are within the normal dynamometer testing tolerances.

To change the focus a bit...I'd worry more about fuel system damage from ethanol than I would about 2 octane points. Our Land Cruiser uses either 89 or 91 octane ethanol-free fuel. Fuel cap shows the international "NO" symbol for E85.

If you're worried about voiding the warranty, read up on the Magnuson-Moss Warranty Act.

 

I would agree with the OP if Toyota wasn't so conservative with their tunes. Heck, if the LX tune is as conservative as the ISF's, it's definitely not good to run lower octane fuels. Even with 93 the isf tune retards timing noticeably. This is why many isf drivers use higher octane fuels or increase the mixture of ethanol. I like to run my engines at peak performance. MPG and saving a few dollars at the pump comes second in my view.

 

What I want to know is where everyone lives that you can find 89 octane gas without any ethanol. Here in Michigan, everything, including most 91 octane gas, has 10% ethanol. You can get 91 ethanol free at some stations, but not all. I know most modern engines that are not flex-fuel, are tuned to run on up to 15% ethanol. I can tell you from checking my mileage the old fashioned way (miles driven/gal filled), driving on the same routes, filling up at the same station and pump, over six tanks of gas, that when I go from 91 no ethanol to 89 10% ethanol, I get 2 mpg more on the non ethanol gas. I would love to try this with 89 no ethanol to see if it is the 10% that is effecting my mileage.

 

The ethanol is most likely the cause of your lower mpg. The more ethanol you run, the lower the mpg. I haven't ran more ethanol in the lx but in case of the isf you're basically trading better performance for worse mpg when running more ethanol. This is because of the lower energy per volume of ethanol.

 

And the only slightly bright side is that your paying just a bit less for ethanol gas...about the last thing I worry about on a $100K ride.

 

This is debated endlessly on the 4 different car forums I follow. Personally, I do what the owner's manual specifies for each of my vehicles. Is it "reqired" who knows? Do what makes you comfortable and be prepared to live with the consequences of either choice you make.

 

So you buy a vehicle thats MSRP at 70000 brand new and that you probably use as a oversized grocery getter. And your concerned about saving 12 bucks at the pump 🤦🏽

 

60,000 miles on 87, no issues.

 

This is a long debate.

I only have personal experience with the 4.7 engines. Our past LX470 required premium fuel whereas our 4Runner with the identical 4.7 (Tahara built) V8 stated regular fuel is fine, but for optimal performance, use premium. We have two failed cats on our 4.7 4Runner at just 110K.

The engine might be the same, but the exhaust system and 4WD are a bit different. The weights are different as well. The LX is at the very top of end of weight and put the most stress on the 5.7 for sure. I do not think the Toyota 5.7 is rated for SAE J2807spec numbers. For example, my 04 4Runner was not rated at the SAE spec, while the 06 4Runner was. So the 381hp for all Toyota models is a bit misleading IMO.

I can't imagine the Toyota engineers made a mistake and put the premium fuel disclaimer in the manual.

Here is an interesting POV from IH8MUD:

 

Actually it's a $90,000 vehicle.

And no, I won't be using it just to get groceries. I'm buying it for the solidity, reliability, the luxury, and the capability to get through any blizzard on my regular trips to upstate New York to see inlaws. It can get bad fast when you're in bmfk Ohio or Penn and bad winter weather hits.

I will also be off-roading the hell out of it, as long as I won't damage the paint. There are tons of places to go mudding/off roading around here.

And yes, it's a waste of money using premium, I'm pretty sure. Lexus wouldn't sell a vehicle made for regular gas, it would throw off the "premium brand" pretense. The motor is completely identical.