I bought a used Lexus RX 350 , Lexus recommends preimum gas. what is your opinion?

I only burn 100LL.

Run what ya want.

WTF would Lexus know, anyway?

They probably own a gas station, or sumpthin.

Those Toyota engineers know what they're doing. My wife's Lexus RX350 and my Highlander had the same 3.5L V-6 engine. Mine was rated for regular unleaded and hers for premium. Different specs meant different octane minimums. Now, having said that, your RX's computer will adjust to almost whatever fuel you put in it, but long-term use might result in maintenance issues. I'd try to keep to their recommended grade if possible.

Up to you.

I run premium in my 2 GM pickups.

Increase in fuel mileage doesn't quite offset the cost like it used to but I still run it.

8-10% increase in mpg for me.

Dont know nutthin about a Lexus but my wifes Audi with 2.0 turbo in it says use premium. When I sneak in regular it sometimes gives a check engine light.

Compression ration of about +/- 11:1
The 2020 model listed at 11.8:1

sounds as if high octane premium makes sense

Didnt any of you Boomers drive any Detroit muscle back in the day with 10:1 slugs ?

Sheesh



Bunch of Matador station wagon homos



Sheesh again

Try to run what the OEM recommends.
Their engineers just might know more than most nitwits.

This nitwit will also tell you that more octane is a waste.
If you don't need it, it ain't gonna do anything for you.

I know you’ve worked in the fuel industry and maybe you can explain to me. My pickup says to run basically whatever, E85/87octane regular, but for best performance or when towing to run 91. Is it because it changes the timing when under load or driven hard due to the computer mapping the throttle input? It can’t be compression since it doesn’t swap the pistons out when you hit the tow haul button.

Like 10gaugemag with his GMs my Ford will show a slight increase in mileage but not enough to offset the cost of Super. My old truck would rattle and knock like dammit on regular 87 under load but the new one I can’t tell a difference.

I think most newer vehicles just adjust the ignition for whatever you put in there. I did a tank of regular until almost bone dry and then premium. No difference in gas mileage or performance. I don’t hear knocking or anything either way.

My Chevy Silverado with 6.2 engine says premium RECOMMED. I run midgrade most of the time with no problem. My wife's Auddi with 3.0 supercharged engine says premium REQUIRED!!! This is right on the gas cap fill area. I only run PREMIUM in it. I think it's important to run whatever the engine calls for.

The manure for the old Cat loader says, use the cheapest fuel that gives satisfactional performance.
If it does not ping. I'd use it.

Manure

I bet you meant manual but those guys on the slang thread will have a hissy fit meltdown.

My wife's Mustang 5.0 is 12:1 compression, premium only. Lots of magic in that car to make it run even on 91 octane (3k feet here) . My old vette is 11.3:1, and 91 octane premium is on the edge depending on timing and temp. But I can get 108 race to blend in from the pump here, so life is good.

It's the cost of performance engines and higher compression.

I use real gasoline, no corn gas in my old 04 Ranger. I is as said earlier it give better mileage but not enough to justify the price. I just don't like what ethanol does when it sits for a while in the tank. I use my bicycle for short hops in town and the Ranger for huge loads of groceries etc. Going to the Liars' Table at the local Mom and Pop restaurant I ride the bike. Be Well, RZ.

Actual compression stroke-by-stroke is dependent on conditions such as RPM and load, and can change as conditions change.

https://www.caranddriver.com/features/a28565486/honda-cr-v-vs-bmw-m5-ford-f-150-dodge-charger/

Manure or manual tranny?

wife's '11 GX 460 says 91 octane

we run mid range 87 (Utah high elevation) & runs great

I run 85 oct in my '03 Lexus LX...purrs like a kitten

non eth 88 oct here is usually .80 cents a gallon more......

WTF joe ?

Damn it, this here owner's manure is full of chit, I don't need no high proof fuel for this rice burner...


lol

This is a bit OT but why is diesel higher than gasoline when it is just a byproduct of gasoline production? Be Well, RZ.

Taxes?


Hell if I know, we just burn it.


Loaded up about 260 gallons today for the pumps, swather and tractors.

One thing about it, chit doesn't get done without fuel.

If the manufacturer says run premium best to run premium. High compression engines don't like low octane fuel and no matter how much your computer can adjust for the induced knock, you are still risking doing damage to your engine. Good way to burn a hole in a piston or burn some valves from predetonation, among other things. Also, might damage your O2 sensors. None of this is cheap to repair, especially on high end cars like Lexus, BMW, Mercedes, etc..... and to top if off, if your computer shows you were running low octane fuel and logs it into your memory, you will probably lose your warranty coverage for all the components involved-

I’m
Guessing the NAZI EPA had something to do with it. 😡

As I understand 87 octane ignites at lower temp than premium? Hence the dieseling effect when you kill a high compression gas engine with low octane?
There is a lot I don't know about engines but I can promise you the Stihl and Echo brand saws run way better on high octane.

Run what you want. Computer will pull timing back till it’s a dog turd, but you aren’t going hurt anything. Try that with a fixed office (ie carbureted) and you’ve got a different scenario.

If the manual says it needs premium, I'd use premium.

My Ford F-250 says to use regular unleaded, but I run the mid-grade always, and nearly always from a top-tier gas brand.

I'm convinced there IS a difference between the upper grades and regular, and between top-tier and the secondary tiers of gasoline.

Many times, you do get what you pay for in fuel.

I have a buddy that used to haul gasoline. He claimed you could smell a difference between fuel racks at the hub. Don't know if true or if it matters but that's what he claimed.

Short term it will be okay. The computer uses knock sensors to control the timing and there will always be a little bit of knock when it is retarding the timing for the incorrect fuel. So long term it's not a good idea.

If they say premium do it.

I tried it in my ford and it worked so much better till they put more corn in.

Use mid grade now.

It costs a little more to get the sulfur out to meet the new road regs.

That’s blasphemy around here to suggest someone actually put in what the manufacturer recommends. After all, a bunch of geriatric geezers on a hunting forum undoubtedly know more about these engines than the 50 lb head engineers that design them.

God forbid someone should actually use the weight of oil they recommend, everybody knows 20W-50 Amsoil is the best oil for every engine ever made.

If you don't want to buy premium you should have bought a different vehicle.

Cheap octane boost stuff????

Most of those octane boost formulas only up the octane by about .1 octane per can per tank of gas.... a total waste of money... Cheaper to either buy the premium in the first place or buy some race gas and add it into the tank when filling

Wife's '01 RX350L rec's regular unleaded.

So, I bought my mistress Buffy, a rebranded ‘yota because only my main broad gets the euro cars. Does a box of minute rice really get that much worse mileage than the long grain brown organic stuff the manual recommends?

Diesel used to require little to none refining; government regulation required removal of sulfur from it and who knows what is now added to it to replace its lubricity.

I know when the requirement went into effect there was a lot of gelled up trucks that year; we only had four but every one of them got put on the hook on one cold day. There wasn't any ULSD No. 1 at the time. 98 or 99 maybe?

No kidding!

Wiper blades, fuel, oil, tires, you name it. OEM recommendations generally provide the longest service life with the least amount of issues. Granted if you have an engineered turd, it was engineered that way and there are few genuine aftermarket fixes for it, unless its a custom repair.

#liftkitsnfattiresdormanrules

Ever pull the heads and look at pistons and cylinder walls? 99.5% of people just use the cheapest they can get. No burnt pistons or broken rings from preignition. Diesel tuners are a whole other story.

One of the things I've heard driving the price, and maybe one of our petro industry folks can clarify it, is that diesel is in high demand elsewhere in the world keeping supply short here. As in an oil company would be foolish to not sell what they can overseas at a higher price than they can here.

Also heard the tax thing is also part of the issue. But supposedly that nasty old supply and demand thing has the most impact.

I run premium in my Lexus. The difference per tank of gas is what, $5?

I run 85 in my truck even though it calls for 87. Never noticed any difference...

My 2018 challenger SRT 392 with 6.4 hemi and our 2020 Yukon with 6.2 engine both get premium fuel..Thats my Detroit muscle ..

My 1970 Hemi Cuda loved Sonoco 260. It drank a lot of it.

10:1 ? That's nothing. I get way more than that building up a fart.

Daughter bought a new 2021 Lexus car this year. It's the second new Lexus she's owned (that I know of). Her previous vehicles were a new Acura and a Lincoln. All were factory rated for premium fuel only. It doesn't make any sense to me to risk voiding the warranty by running regular grade gasoline in vehicles as expensive to buy and repair as they are.

It's mostly timing. As others have posted


You have knock sensors in the engine, any knock, timing is reduced.
Then, I suppose, it true to advance, senses knock, retard.
It happens numerous times a second.

Other issues concerning knock are design of combustion chamber, smoothness in the chamber, carbon deposits, and many high compression engines today use direct injection. In short, anything in the chamber that
is an edge or sticks up, will get hotter and provide an ignition source.

You could get better mileage from higher octane in an engine with
enough compression to use it. Essentially yielding more power from
the same amount of fuel. So you don't need to give it more to go uphill,
or drop a gear.




Rusty,
Don't take this as an intended insult.
But your statement is BS.
Diesel is not a "byproduct.
People who drive cars and operate in a world of just cars believe that.
Individual transport in the US is gasoline dependent.
But any commercial fuel is diesel.
Train, trucks, ag, and any heavy equipment. Has been for decades.
Only equipment you can manually move on a construction site is gas.
The amount of fuel burned for heat in the Northeast is tremendous also.

Much of the rest of the world uses diesel in their personal transport.
We don't because of EPA, initial cost, 1st world snobbery, and because
we don't place a huge priority on economy, dependability, or longevity.
We buy shiny and flashy, and new car buyers trade often.



Historically, kerosene was the desired product. For lighting and cooking.
Gasoline was byproduct. Pumped into ditches and burned.
It did take awhile for diesel to grab its market.
Today's cracker refineries can be much more selective in the yield
of a barrel of crude. So they can determine to produce more of certain
products. And diesel is desired.

If it says premium then use it or get another vehicle. It's all in the compression ratio. We have a vintage 2002 Z-28 with the 5.7 and it says premium only. My son has an old Maxima DOHC V6 and it too says premium. He tried running regular once and the valve clatter was pretty obvious.

What's your elevation? If you're above about 2000', regular is just as good as premium. Octane increases with reduced air pressure. Cars are set for close to sea level and need higher octane there but as you go up, the octane requirement drops. Our Toyota Highlander runs great on regular here at 4k but not worth crap below about 2k.

Boise 2700'

Modern turbos don’t give a hoot ‘bout elevation. If it needs 91 at sea level, it’s going to want it at 6000’.

that's true with high compression engines but most cars run just fine on 85 octane at higher elevations. In most of the mountain states, they don't even sell 87. It's all 85 or 91.

My 04 180K Tahoe throws the Service Engine light every time I hit the interstate[often], always about 25 miles out.
It mostly flashes for the rest of the trip[rarely does it stay on steady].
The next day it goes off within a few minutes of driving, so it's rarely on or flashing by the time that I can get it checked.
The code is always the same 'all cylinder misfire', mileage nor performance is ever affected?
Once I filled it with premium due to station being out of or pumps down on Reg/Mid-grade, no flashy light.
I guess it's from engine knock?

Uh I heard high octanes gas would burn my motor up

Unless you are gonna be running it hard, Regular will work just fine.

Just the opposite- high octane gas will never hurt your engine regardless if it is designed for low octane fuel... however, low octane fuel can do serious damage to an engine with high compression due to preignition. What most people don't realize is high octane fuel is actually harder to ignite than low octane fuel, which can cause problems with high compression engines, which require fairly accurate ignition timing to operate properly and that works easier with high octane fuel...

Reaford,
could be a number of issues. If it's knock, you might sense it, might not.
No idea your mechanical knowledge, but we many call it "valve clatter".
No idea what happens if a knock sensor goes tits up. You do not want to be running a knocking engine. It will ruin the pistons.


Sheister is 100%!

For what it's worth, and as relayed to me by a friend.
The Husqvarna Tech Training course had a demo of two containers of gas burning. 87 and 93. Both top tier. And before ethanol.
The 87 had noticably more smoke.

Then they had two identical saws, tuned the same,
strapped down and running wide open, with a temp sensor beside the
sparkplug. Both running the synthetic premium mix oil, but one had 87 and the other 93. The 93 saw was running noticably cooler. They then dumped the fuel, swapped the fuel between the saws and reran the test just to prove tuning wasn't the issue. Same results.

Their explanation was that premium fuel was cleaner. And that those
dirty elements were the cause of the extra smoke and heat.

Don't forget airline travel and transport...also NOT gasoline in the commercial fields.

does randy's semen taste better than high octane?

Hawk,
Intended to mention jets, forgot.

You know jet fuel?
Real dangerous stuff.
Worse than gasoline! After all, it is the fuel for them powerful jets!

This should be interesting!

I’ve had my 2007 Lexus IS250 for 14 years now. 220,000 miles. Very very few repairs to the car - no internal motor problems. The motor runs incredibly well - the car still puts a smile on my face when the road allows me to push the car hard. I always run Premium, just as Lexus recommends. Each of the two sets of spark plugs were going strong when I replaced them at 100,000 mile intervals.

Yep, Premium costs more - but the results with my car have been tremendous.

I see you're in Dallas, elevation under 500'. You need premium as recommended. If you were in one of the mountain states, elevation much higher, you would get the same results with 85 octane.

Which fuel grade should I use for my Lexus vehicle?

'03 Lexus LX shown here at 9000'

Tank full of 85 regular octane

Runs great !

They've updated that in the 2020 manuals, 6.2 required it or face possible engine damage. I think the 2019 manuals only said recommended. Atleast thats what my 2020 sierra one says.

There are at least 8 or 10 places in Boise, more throughout the Treasure Valley where non-ethanol is available at about 15-25 cents a gallon more,
Unless on vacation it's the only gas we have put in any internal combustion engine we own for at least a decade
I haven't checked in a while but when I did it would cost more to fill up but we gained enough extra miles per tank full that driving cost per mile was less, and a 4 banger had more power up hills.

I use regular in the Matrix. My '81 Dodge pickup needs premium. All of the motorcycles get premium. The chainsaws get premium just to avoid ethanol (ethanol is one of the greatest frauds ever perpetrated). The lawn mower gets premium for the same reason. Watercraft get premium. I avoid bio-diesel for the diesels too. GD

Raeford- that OR the problem was merely your gas cap not on tight enough at first.

That is the cause of a lot of Check Engine Lights

Not sure how it is there, but everywhere around here that I get non-ethanol gas for my boat and other off road purposes, it is always premium 93 octane or better... I've never seen it around here when it wasn't high octane ... of course, the price is correspondingly high also....

I tend to think like you, but am fully aware that engineers lay awake nights thinking up things to complicate us peons' lives, and giggling about it over drinks at their conventions.

I am convinced of it!

Had a 1998 Landcruiser 4.7L V8 that said run premium; I ran regular. For, 276K miles. NO problem

Always make sure that I hear many clicks when tightening gas cap.
I never hear any knocks or valve clatter and it runs smooth and strong as ever.
Damn light is annoying as hell when flashing at you!!

Brother's Grand Cherokee doesn't even have a traditional gas cap.

Neither does the Jeep Renegade...

German engineers more so than others . . . damn krauts!

Wifey ran the cheap stuff in her BMW when it said use premium. Dicked up the injectors

North plains, Fred’s marina and dobsons on the Columbia have 87 or at least did. The price is even higher than LO 93.

I’m just running ethanol now and trying to burn it fast enough it doesn’t sit long in the boat.

I usually get my nonethanol gas for my boat at the North Plains Chevron and I'm pretty sure it is premium grade 91 or 93..... same in Cornelius at the Space Age station- Premium 91 grade only in non ethanol...

The Studebaker R/4 has a 12:1 compression ratio.

I use only non-al in all of my small engines and my RZR. Only the cars get alcohol. I've tried non-al in our van and the tiny increase in mileage didn't offset the higher price. Our Toyota says to use 87 octane but at our altitude, 85 works just as well. When we travel west, any place west of Boise is lower and 87 is required. Around here, all of the stations sell 85 and 91, no 87.