Regular Or Premium Unleaded Fuel?

[Toysrme]

The reason the car makers tell you to use the high octane is that you get the best (lowest)emmission results.

just a little 6 banger

That is just so wrong on so many levels.

1) Octane increases emessions, not decrease it.

2) Remember that back in the day, high compression when the nice v8's first started coming out were 7.5:1. Modern N/A engines are not only atlease 10:1 compression - they also develope two, or three times the power for the same displacement.

You do realize that ever descent output v6 of the last few years can not run 87 octane without pinging like crazy? You also realize that without knock control systems in place - you'd be knockling like crazy on your 2jz-ge the next time you passed 1/3 throttle?

Remember, knock control is a passive device. It doesn't "fix" pre-ignition, they react to it.

That being said, if the OEM states it can run 87 octane - always safe your money & use it. If they state will run on 87, but needs higher octane to preform well, it's a toss-up.

I don't like answering old questions, but no I wouldn't use E85 after having used a few tanks of it before. Performance, and mileage is unbelieveably low. These engines are also not rated safe to use it with.

It'll get you home if you're out of gas, but that's about it.

[BLAZER]

I don't get it,here in Ohio the difference between 93 octane and 87 octane is usually 20cents or less.thats less than 4.00 a tank. why would you not go with recommended higher octane.

[amf1932]

I don't get it,here in Ohio the difference between 93 octane and 87 octane is usually 20cents or less.thats less than 4.00 a tank. why would you not go with recommended higher octane.

←

Because I don't feel like throwing $4.00 away! B)

[EdMcK515]

My dad bought a used 96' ES300 with 55K miles. Hasn't used anything but Regular grade gasoline, he got it up to 150K miles with it still running perfectly fine. I am now driving it and using regular grade and noticing no problems what so ever.

[backwoods lex]

Without a doubt, I can tell a difference on my vehicle. I use 93 in my car, and the performance is better. Not a lot better, but better. I think the best way to observe the difference is not to switch from low to high test, but instead regularly use high test and then try a tank of 87. It is so much more sluggish for me.

[ktranne]

93 here in GA.

[aggiez28]

any one that tells you that it does not matter what fuel of octaine is a complete jerk off, its plain and simple the better octaine the better proformance, dont every go lower

ignorance at its best........

[lancesavage]

I have responded to this question a few times over the years. I have a 2000 GS300 and it has been on a constant diet of 87 octane since 2002. My own evaluations of performance yield no change in gas mileage, or any significant difference in performance. My vehicle just turned 100,000 and when it was taken in for its 90K mantainance (OK I was a bit late) they told me everything checked out fine. I also did my own borescope inspection and the cylinders/valves look ok. Never once heard any pinging even when I put a load on it by flooring the acelerator.

If you ask any of the mechanics at Lexus you will most likely get a response similar to others posted here. I heard the same thing from the Mercedes mechanic and ran my E320 for about 9 yrs and 230k on low octane. I have had lot of incorrect and just utter BS thrown at me from mechanics. These are the same guys that would have you spent $5.00/qt for synthetic motor oil and tell you to change it every 3k when $1.50/qt stuff that meets the API requirements will work fine and will run for 5k like the manual states. I wouldn't worry about putting low octane fuel in you car. You're engine will be just fine and you will save .30/gal. That adds up.

Lexus recommends Premium (91 octate) fuel for my "new to me" 2000 GS300. Anyone tried using Regular (87 octane) or mid-grade (89 octane)? What, besides pinging could I expect from using the lower prices and lower octane grade?

I have not seen any posts on this topic before and would appreciate some tecnical as well as non-tech replys.

Thnks.

[steerg]

We have used 87 octane in our '97 ES300 since it was new. Now has 137,500 miles on it and it runs like a swiss watch. The computers in the engine adjust almost immediately to the lower octane.

Lexas and others recommend premium gas because it will up horsepower sightly and also fuel mileage. However, the small difference will never offset the price differential between regular and premuim and you will never notice the hp loss.

The car doesn't care, but your wallet may.

[webs]

any one that tells you that it does not matter what fuel of octaine is a complete jerk off, its plain and simple the better octaine the better proformance, dont every go lower, your car will feel sluggish,

I THINK YOU SHOULD GET ONTO THE AMERICAN PETROLEUM INSTITUTES WEBSITE. WWW.API.ORG

SEARCH "OCTANE" FOR ALL RELATIVE ARTICLES. YOU MIGHT GET SCHOOLED BY SOME PEOPLE WHO REALLY KNOW THE SUBJECT.

We have used 87 octane in our '97 ES300 since it was new. Now has 137,500 miles on it and it runs like a swiss watch. The computers in the engine adjust almost immediately to the lower octane.

Lexas and others recommend premium gas because it will up horsepower sightly and also fuel mileage. However, the small difference will never offset the price differential between regular and premuim and you will never notice the hp loss.

The car doesn't care, but your wallet may.

I have a gs300 and my response would have been exactly what you just said. Why waste money for no real benefit. With my little 6 cylinder, I think anyone who says they get better performance is making an emotional judgement. I don't get any better mileage or performance by changing octane. Also, check the website from american petroleum institute ( www.api.org) search "octane" lots of articles that will dispell a lot of the rumors on this site.

[mburnickas]

We have used 87 octane in our '97 ES300 since it was new. Now has 137,500 miles on it and it runs like a swiss watch. The computers in the engine adjust almost immediately to the lower octane.

Lexas and others recommend premium gas because it will up horsepower sightly and also fuel mileage. However, the small difference will never offset the price differential between regular and premuim and you will never notice the hp loss.

The car doesn't care, but your wallet may.

Even Dyson Analysis said to use the cheap gas in the my ES300. I only use FP60 in my gas (add) and so far, the $0.20 delta in price is saving me money....

[Rx330driver]

lol how many and how long have these threads been goin on. I dont know what is better but i stick to premium Chevron only 91 octane. I dont care if it doesnt matter what brand or what octane, i feel better inside if i know that my car is betting the best money can buy. For goodness sakes, its 20 cents more a gallon, probably equally out to less than 3 dollars at the pump. thats just one less cup of coffee from starbucks every 4 days

[poway]

My 1991 LS 400 with 220,000 has been burning 87 unleaded for the last 25,000 miles. No problems, that I've detected.

[lilgreek]

i've got a 91 ls400.....250-400 miles/day......use 87 octane w/ no problems, sluggishness, etc......oil changes approx. every 2 weeks...

[Lexxxuss]

so cud dat b da reason y engine light is on for my lexus es300 92?

i took it to da dealer nd he told me da code 25 whch is Air–Fuel Ratio Lean Malfunction.

If i start using just da premium oil...wud it solve da problem?

I remembr after i bought da car couple months back, I did put in da premium once nd den switched back to regular nd couple days later da engine light showed up.

[mikek753]

so cud dat b da reason y engine light is on for my lexus es300 92?

i took it to da dealer nd he told me da code 25 whch is Air–Fuel Ratio Lean Malfunction.

If i start using just da premium oil...wud it solve da problem?

I remembr after i bought da car couple months back, I did put in da premium once nd den switched back to regular nd couple days later da engine light showed up.

one way or another you'll need to replace O2 sensor - IMHO

you got this code as result of O2 sensor got "lazy" and ECU can't get reading as fast as it needs.

using premium will just delay O2 sensor replacement.

And check with trusted mechanic about this. As Lexus gives recommendations of using Prem gas for almost everything ...

[g4driver]

FIRST...

In Europe and Australia, an octane rating (such as 96 in Germany) is a direct measurement of the Research Octane Number (or RON) which is measured by running the fuel through a specific engine under very specific test conditions.

In the US, Canada and a few other countries, the octane rating on the pump IS NOT the RON. It is derived by summing the RON and the Motor Octane Number then dividing the result by two. The Motor Octane Number is a completely different (and more stringent test) that simulates running the fuel through an engine in more stressful conditions. As a result, the Motor Octane Number is usually 8-10 points LESS than RON for the exact same fuel. Since the octane rating displayed on North American pumps is one half of the sum of the two ratings, the same fuel will have an octane rating displayed of 4-5 points less than what would be displayed in Europe and Australia for the same fuel. So if that German fuel with a 96 RON were brought to the US or Canada, it would be advertised as 91 or 92 octane fuel.

I put 93 Octane fuel in my LS-430 and this would be advertised as 97 or 98 Octane in Europe.

SECOND...

Octane has no direct effect on the deflagration (burning characteristics) of a fuel. In other words, higher octane fuel does not burn faster than lower octane fuel. It's sole effect is on detonation effect and that's because higher octane equates to a higher activation energy - the energy necessary to begin the chemical reaction we know as either combustion or detonation. Since a higher octane has a higher activation energy, it is more resistant to detonation.

THIRD...

Octane has no effect on the energy per unit volume of a fuel. All other things being equal, one liter of 89 Octane has the same inherent stored energy as one liter of 93 Octane. HOWEVER, most fuel manufacturers formulate the fuel that will go into making a higher Octane fuel with more energy per liter - creating a more powerful and quicker burning fuel.

FOURTH...

In Russia, the standard octane is 80 RON. Now how'd you like to run your Lexus on that crap??? !!!

Cheers

[Ny LeX BaLLa]

WITHOUT A DOUBT USE THE PREMIUM GASOLINE....the car will run and stay in pristine condition...i once filled up at a full service pump..after asking for "fill it up premium (93 octane)" i turn around to pay the attendant through my window, and i notice him removing the pump and replacing it in the REGULAR (87 OCTANE) holster....needless to say that attendant had a long day...the car was totally changed..sluggish, slow, DON'T MESS WITH ANYTHING BUT THE BEST!!!!!...no questions

[amf1932]

WITHOUT A DOUBT USE THE PREMIUM GASOLINE....the car will run and stay in pristine condition...i once filled up at a full service pump..after asking for "fill it up premium (93 octane)" i turn around to pay the attendant through my window, and i notice him removing the pump and replacing it in the REGULAR (87 OCTANE) holster....needless to say that attendant had a long day...the car was totally changed..sluggish, slow, DON'T MESS WITH ANYTHING BUT THE BEST!!!!!...no questions

It's all in your head my friend!

P.S. Unless you have a high mileage GS that has a carboned up engine. Than, and only than will a higher octane fuel show a difference in performance.

[mburnickas]

Thank you! I use 87 ($2.45) and always will (if I can). I just add FP+ or NEUTRA 131 to it and get another 1.25 to 1.5 MPG more. Lucas UCL did NOT add any MPG to my miles.

[vicmostlexmost]

:D Premium!

If you run a lower octane your car will ping for awhile. The computer will sense this through a "knock sensor" and will !Removed! your timing until the pinging stops. This cuts down on the efficiency of your engine (performance) AND fuel mileage. It actually costs you less $ per mile to run Premium than regular.

Lexus Tech...

(

I say premium as well. Also note that the lower grade fuel burns quicker and I have heard that your car will not perform to it's peak capabilities. You do not want to put anything cheap in that expensive car of yours? :D

[kc82]

Lexus recommends Premium (91 octate) fuel for my "new to me" 2000 GS300. Anyone tried using Regular (87 octane) or mid-grade (89 octane)? What, besides pinging could I expect from using the lower prices and lower octane grade?

I have not seen any posts on this topic before and would appreciate some tecnical as well as non-tech replys.

Thnks.

if u can afforce lexus da mean u gotta pay more. premium!!!!!!!!!!!!!!!!!!!!!1

[Deepak Gandhi]

I only use Sunoco Super 94 octane....

Where can you buy 94 octane? Is it at some special super gas station or what?

Sunnoco gas stations sell 94 octane

[GoPlay!]

Lexus recommends Premium (91 octate) fuel for my "new to me" 2000 GS300. Anyone tried using Regular (87 octane) or mid-grade (89 octane)? What, besides pinging could I expect from using the lower prices and lower octane grade?

I have not seen any posts on this topic before and would appreciate some tecnical as well as non-tech replys.

Thnks.

if u can afforce lexus da mean u gotta pay more. premium!!!!!!!!!!!!!!!!!!!!!1

I have 41k miles on my RX350. Recently our gas prices were $5 per gallon I used medium grade every other fill up to see if it mattered. Clearly the gas mileage is best with the premium gas. So, it doesn't matter the price (well, for fun I will tell you I paid $1.78 for a fill-up today); who wants to fill up more often? Not me. I'm not fond of the task of filling the tank so the price difference is worth eeking out a little longer milealge. Just one gals opinion. ;)

[socal3]

91 Is as high as I can get in California and that's what I use