$$$$.....Regular Fuel makes a real difference.
The RX350, ES350, ES300h, NX300h, and CT200h are all tuned to run on regular 87. Everything else from Lexus requires minimum supreme 91. Modern engines and ECU's are smart enough to adjust for knocking and pinging when a lower grade fuel is used, though in the long run its best to run what is required. Recommended is more at discretion.
Last edited by Hoovey689; Sep 23, 2016 at 07:06 PM.
Lexus Fanatic
Joined: Oct 2003
Posts: 94,702
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From: Virginia/D.C. suburbs
Well, in most areas of the U.S., ALL gasoline is diluted with 10% Ethanol (E10) per EPA mandate. California (CARB) has even more restrictive rules in high-smog places like L.A.
Lexus Champion
Joined: Apr 2007
Posts: 11,119
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From: Southeastern PA
By the name of the fuel alone, some marketing genius was able to milk money from people unaware of what they're buying. By calling it regular, mid-grade, and premium they imply a quality of the fuel rather than chemistry. Genius. Many folks took hook, line, and sinker. The reality, as many of us know, is that fuel chemistry is important for a machine devised to control an explosion, harness the energy of that explosion, and to move a larger and heavier machine without going into an uncontrolled explosive state that could damage the machine or its operators.
And so car companies jumped on this bandwagon of confusion and provided unnecessary recommendations to make people feel that their premium, expensive machine somehow required "premium" fuel, also at a higher price. Our 4GS machines actually require this chemistry to operate properly and achieve the advertised performance at a ~ 11.5:1 compression ratio. Sure it runs with "regular" 87 octane fuel courtesy of its knock sensor to protect the machine. Compare that to an Acura running at 10:1 compression ratio which "recommends" "premium" grade fuel, and a Honda engine at 10.5:1 that "recommends" "regular" grade fuel.
So my 4GS drinks the expensive stuff and she needs it. Others just drink it because they can.
And so car companies jumped on this bandwagon of confusion and provided unnecessary recommendations to make people feel that their premium, expensive machine somehow required "premium" fuel, also at a higher price. Our 4GS machines actually require this chemistry to operate properly and achieve the advertised performance at a ~ 11.5:1 compression ratio. Sure it runs with "regular" 87 octane fuel courtesy of its knock sensor to protect the machine. Compare that to an Acura running at 10:1 compression ratio which "recommends" "premium" grade fuel, and a Honda engine at 10.5:1 that "recommends" "regular" grade fuel.
So my 4GS drinks the expensive stuff and she needs it. Others just drink it because they can.
Lexus Fanatic
Joined: Oct 2003
Posts: 94,702
Likes: 290
From: Virginia/D.C. suburbs
Additionally, some people just keep doing what they always did. When I was a kid, I had a '78 Malibu wagon. It had horrible knocking, and I frequently needed to use "high-test" fuel to stop the knocking. At some point, I became pro-active instead of reactive, and just used the higher octane as a matter of course, because the knocking was so frequent. I guaranty that there are plenty of people who still think you need to do this, so they just automatically but higher octane.
Lead Lap
Joined: Mar 2015
Posts: 4,611
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From: In your head
Can journalists stop using Clickbait or terrible titles on their articles.
1) The article talks about those drivers who have a vehicle speced for 87 but choose to use 91. Not good since the cars timings are designed in mind for highest economy. 91 inside it is going to do nothing. Only had time to scan the article but can anyone verify if they tried dumping 87 in a 91 specd vehicle?
2) The article still recommends that drivers use only the fuel level specd in their manual. So if your car say 87 use 87, if 91 use 91 only
3) The article also points to Top Tier Gasoline to address quality concerns some have with their fuel. If you feel that a non brand name fuel station maybe messing with the gas in regular or giving you lesser quality 91 then use Top tier since it has to be certified (whatever that means who know. For all you know, its just a sticker and permission to charge more per gallon without any actual benefit)
1) The article talks about those drivers who have a vehicle speced for 87 but choose to use 91. Not good since the cars timings are designed in mind for highest economy. 91 inside it is going to do nothing. Only had time to scan the article but can anyone verify if they tried dumping 87 in a 91 specd vehicle?
2) The article still recommends that drivers use only the fuel level specd in their manual. So if your car say 87 use 87, if 91 use 91 only
3) The article also points to Top Tier Gasoline to address quality concerns some have with their fuel. If you feel that a non brand name fuel station maybe messing with the gas in regular or giving you lesser quality 91 then use Top tier since it has to be certified (whatever that means who know. For all you know, its just a sticker and permission to charge more per gallon without any actual benefit)
My fuel cap says 93 octane minimium, while all I can get here is 91 max.
btw, for a engine like mine, I can clearly tell Shell premium is way better than chervon 91, while they are both tier 1 gasoline. Fuel mileage suffer though, I get at least 15 mikes less off a tank, but the car runs much smoother and eager to rev
btw, for a engine like mine, I can clearly tell Shell premium is way better than chervon 91, while they are both tier 1 gasoline. Fuel mileage suffer though, I get at least 15 mikes less off a tank, but the car runs much smoother and eager to rev
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Lexus Fanatic
Joined: Nov 2011
Posts: 35,651
Likes: 426
From: ON/NY
Doesn't it say use premium on the gas door flap?
Intermediate
Joined: Feb 2016
Posts: 489
Likes: 22
From: CA
No, my manual says nothing about 'reduction of performance', or 'significant' to boot. It is a known thing that it is useless to use gasoline with higher octane than absolute minimum required. It won't get you any more performance. The Lexus official at the dealership responsible for explaining the technology and acquainting you with the car told me without me even asking - you do NOT need to pour gas higher than 87. The bottom line - you may subscribe to a belief that you are losing some (meaningful/measurable) performance by using the regular - but it is like a religious belief, it is not grounded in any data.
Lexus Fanatic
Joined: Nov 2011
Posts: 35,651
Likes: 426
From: ON/NY
No, my manual says nothing about 'reduction of performance', or 'significant' to boot. It is a known thing that it is useless to use gasoline with higher octane than absolute minimum required. It won't get you any more performance. The Lexus official at the dealership responsible for explaining the technology and acquainting you with the car told me without me even asking - you do NOT need to pour gas higher than 87. The bottom line - you may subscribe to a belief that you are losing some (meaningful/measurable) performance by using the regular - but it is like a religious belief, it is not grounded in any data.
Intermediate
Joined: Feb 2016
Posts: 489
Likes: 22
From: CA
'Optimal' is a vague word, it is poorly defined. How optimality is exactly measured? Are you losing 1% or 0.1% of performance? It is a placebo statement, there are many overly cautious statements like that in the manual - like do not put transmission into park while the vehicle is moving.
Lexus Champion
Joined: Sep 2016
Posts: 2,047
Likes: 135
From: AB
In my neck of wood, my family uses only Shell premium. Ours cars calls for high Octane gasoline. Can feel when other brand is filled. Well, Porsche engine has knock sensor on each cylinder. ECU will adjust timing when wrong fuel is filled. Also Ethanol blend, too much is bad for the engine.