how many of you floss after each meal? No? Well why not, don't you know how expensive dental work is? Don't you know that dentists recommend it so that you avoid expensive problems down the road? Don't you just get peace of mind knowing your teeth are as clean as can be? Exactly.

 

Except you don't actually save money on fuel when an engine is optimized for best performance on high octane vs. low octane. You actually end up spending more money in the long run. So if you were trying to be economically wise, you'd use the highest octane (up to 93) and you'll get best performance. Win/win.

I already did the economics on a spreadsheet for the bmw bois back in the day. They used to do this same 100-page argument then I basically turned all the 87 octane in high performance engine fans into powder when they argued they saved money.

On cars optimized for 87, by all means, do not use 91/93. That's just dumb. Always use what your engine runs best on, as high as the manufacturer recommends.

 

LOL prove it.

At $0.60 difference per gallon, at, say 23 MPG average, over 300k miles (which this car will easily do, using 87 on every tank, just like any other Toyota) is $7826.08.

There is no way in hell that running 87 in a glorified Camry is going to do $8k worth of... anything. No ****ing way. Maybe in an over-designed, expensive to repair BMW. Toyota is smarter than that.

On the topic of power loss, at Denver's elevation I am already losing 50-60 HP. What's another 5-10? Who ****ing cares? These cars are NOT fast!

 

yea except I have A/B both premium and regular and I get no difference whatsoever on the exact same commute, 23mpg no matter what. Also the price difference from regular to premium is much larger in Canada than the USA. right now it's 26 cents per liter gap which converts to about 0.98 cents per gallon. My 20k miles a year at 23mpg means about 869 gallons. Save a dollar a gallon means $869 a year buys about 3 track days or a new set of performance tires every 2 years. Or an exhaust, coilovers, wheels, whatever you want to spend that on rather than gas.

To make up the 32% higher fuel price, I'd have to jump from 23mpg to 30mpg when switching to premium. Does that sound realistic?

Like I said, in my turbo car tuned to an inch of it's life, the difference is blowing up an engine or not blowing up an engine. In the lexus, the difference is literally negligible, you guys are just fussing over nothing.

 

Where the heck are you getting gas that costs 32% more for 91? Im in Canada...I just got 91 for only 18 cents more than regular costs, I get roughly a 10% increase in fuel economy when using top tier vs cheaper gas stations.
Also, while you won’t blow up the engine you are 100% guaranteed losing performance and efficiency...how much only Lexus engineers know but there is no way you’re putting 87 in a 11.8:1 compression engine tuned for 91 and not losing some.

I get doing that in a civic si or something but doing that in a 50k Lexus with a very high compression V6 makes no sense to me. You bought a 300+ hp car but don’t want to put 91 in it? Lexus states using less than 91 in this vehicle can cause knocking and Lexus states they can void your entire engine warranty if they discover you use 87. Based on just that you’d think you would use 91,let alone the power and efficiency your losing.
But hey like you said you can go to the track 3 more times, which I gotta admit is confusing because if you drive your car that hard and are competitive enough to attend track days I don’t get why you would put 87 in it....

 

I just wanted to point something out. The compression ratio keeps getting brought up, and I even did earlier. However, compression alone doesn't mean high-octane. The latest Toyota Corolla, for example, has a 2.0-liter engine that has a 13:1 compression ratio and runs on regular fuel.

Having said that, it also doesn't make astounding amounts of power for its displacement (169 hp). At the time the 2GR-FSE was released, its specific output was actually high for the time. Now, not so much. But, in order to get that peak level of performance back in 2005, 91 was absolutely needed.

 

right now local gas station down the block in Edmonton is 0.94 for reg and 1.24 for premium which is 32% increase. And like some people have pointed out, 300hp is not a fast car. The IS is a "sporty" car not a sports car, I commute with mine and track my sport bikes or my miata which puts out more power and weighs 1000lb less and even that isn't a fast car. I really don't see the argument because the lexus is a 50k car I must do this and that. How much is my life worth? Maybe a couple hundred grand according to my life insurance policy. And yet do I sometimes still eat fast food and drink and have the occasional cigarette? Why don't I only put the highest quality organic food in 100% of the time?

 

I'm gonna have to share this with my dentist in-law who drives a BMW.

 

For those unsuspecting readers, at 20 cents extra per gallon for premium and at 20 mpg you would have to drive 50,000 miles a year to save $500 that year.

 

Where are you buying premium that it's only a $0.20 difference? It's at least $0.50 more around here, usually $0.60.

 

Agreed, recently, here in the KC area, premium has been around $2.50 a gallon, versus regular at somewhere around $1.90.

 

My point is if you have the money for a 50k car, and said manufacturer recommends 91 why wouldn’t you? And you said you take your car to the track where every pound, every HP & every millisecond counts but you don’t want to use 91 in a IS350?? What??

Do you put the cheapest tires you can find on it?
do you use the cheapest brakes you can find?
do you use the cheapest oil?
Do you hire the cheapest mechanic you can find?
Do you use the cheapest wiper blades?

Personally I wouldn’t even buy a 350 off someone if I i knew they used regular... Again, is the engine damaged? Nope. But reflects on the character of the seller which is something an experienced buyer like me takes into consideration, if someone didn’t give a **** about there car, I wouldn’t buy it.

Hundreds and hundreds of is350 owners drop 500-600$ on the RR tune for a 10whp gain, then you have someone like yourself probably losing that much just to save a few bucks, which is again confusing as hell because your talking about track days where EVERYTHING counts.

And your dentistry reference makes no sense, if they told me flossing only once a day will cause me to lose teeth the way you refusing to use the correct fuel on your vehicle causes you to lose power and efficiency then yes, I would floss after every meal.


Ultimately, this isn’t even a debate. If you want the advertised/maximum performance and efficiency out of your 2GR-FSE engine, you use 91. If you don’t care about a few HP, which you think a guy with 300+ HP Sporty car who goes to the track would, use 87. But like I said, according to Lexus they will void your engine warranty for that, something I don’t think they would do without reason.

if you live at or around elevation obv it’s a different situation.

 

Ouch. Southern California. Difference between 87, 89, and 91 almost always 10 cents per gal between each octane level. So 91 is 20 cents more than 87. I have seen it 30 cents more, but commonly 20 cents.

Likely supply and demand difference I guess.

Edit: Cheap gas station near me has 87 for $3.10 and 91 for $3.30 right now.
"Cheap" for here lol.
When you hear on the news they're talking about gas nearing $5 / gal in the country...they're talking about us. Crazy here.

 

Pure 91 octane gas most of the time. Sometimes we used the Costco premium due to it being extremely cheap for a while, but it has 10% ethanol in it.

 

I ran E10 91 in the IS most of the time I had it. Personally I feel no shame for that and still won't refuse to use gas because of ethanol. Even the 93 I put in my GTI now doesn't explicitly state that it's ethanol free, but I am not worried about it. Car's designed to run on it.