NFT: Mixing octane percentages in your car's gasoline?

Newer than roughly 2008 you should put 89 in your car and not care. Knock sensors will retard timing and fix the problem electromechanically.

Older car, well. Just put 93 in it and stop worrying about 10 dollars for a 15 gallon tank.

10 gallons 89.....you bought the car knowing what it needs. Don't be cheap on the gas or those valves and pistons will let you know.

$4.50 per fill up (per MA AAA averages for 89 vs 93 octane), or say $20 per month if you fill up weekly, $240 per year that could cost you thousands in the long run.

but with the advice of several dealer mechanics (starting with my G20 decades ago) I have driven a long series of cars "requiring Premium" who told me unless the engine talks back (and then change) you are doing no damage, the systems usually compensate. (No two engines from the same model are exactly alike so they recommend at the lower tolerance.)

The tradeoff is that you will get better mileage with the no ethanol or higher octane mixes.

a car that requires 91, you can afford a few bucks for 93. Come on man.

In comment 16297473 Chris in Philly said:

Quote:

a car that requires 91, you can afford a few bucks for 93. Come on man.

lol I was about to post the same thing

I was buying 110 octane fuel...leaded.

Rocket ship.

In comment 16297473 Chris in Philly said:

Quote:

a car that requires 91, you can afford a few bucks for 93. Come on man.

This is the answer and it’s the only reason Milton even posted this. He’s not confused on the gasoline. He wants us all to think he’s filthy rich and drives an expensive car but we all know he clunks around in a 2002 Toyota Corolla

In comment 16297480 BigBlueShock said:

Quote:

In comment 16297473 Chris in Philly said: Quote: a car that requires 91, you can afford a few bucks for 93. Come on man. This is the answer and it’s the only reason Milton even posted this. He’s not confused on the gasoline. He wants us all to think he’s filthy rich and drives an expensive car but we all know he clunks around in a 2002 Toyota Corolla

It's a 2010 Lexus LS460 with 150,000+ miles on it. Impressed?

Gas stations only have regular and premium gas in the storage tanks. Midgrades are blended at the pump.

Is that if your car requires higher octane gas you should go ahead and use it because the gas mileage will improve enough to make up for the added cost of a fill up. So mixing octanes is ok but not worth the bother.

You’re talking about a total cost savings of 300-500 for the entire year! depending how much you drive. Is that worth the risk of destroying your engine?

to use 91 octane which I used. Wife took it out and put 87 in because that is what she used in her car, not thinking. First time I stepped on the gas after that fill up it was like a dud - slow response. All the engine did was retard the timing to prevent knocks, so the accelaration was lacking.

In a 150k mile engine, you can likely use 89 octane safely unless you like doing burnouts.

is a mechanic. Right now he works for a Ford dealer, but over the past 30 years he has worked for BMW, Volvo, Honda, and his favorite, Saab (he is a Swede).

He says if the manufacturer recommends a specific octane for gas you should use it. They aren't in cahoots with the oil industry trying to get you to pay an additional 30 cents per gallon unnecessarily or do things unnecessarily. He did have reasons and explained the resulting impact (engine knocks, etc.) but it could also impact the life of the engine.

In Milton's case with a 2010 vehicle engine life has probably proved itself but is it worth the pennies/dollars saved? Not in my opinion.

Milton can always drive to Maine where I believe they do have 91 octane and use whatever savings he gets on the price per gallon in miles traveled.

I think we've settled on just getting the 93.

But where you get your gas is equally important. A family member was having car problems and the local mechanic asked 'are you getting gas from the guy around the corner' (the answer was yes). Said that was the problem bc their gas is crap and then gave her a list of the stations in the area to avoid.

The reason I was asking is because I'm gonna be taking a 160-mile drive down to NYC for Thanksgiving and heading back the same day. The car has a 21-gallon tank, so a full tank should get me there and back without needing a refill. I currently have a little more than three quarters of a tank at 93-octane, so I was thinking if I top it off with 87-octane before leaving (to go from 3/4 of tank to a full tank). At the gas station I generally go to, the 93-octane is a full dollar more than the 87-octane (but only 20 cents more than the 89), so for every tank of gas, that's a $21 difference, and unfortunately the car only averages 18 mpg through my normal driving (it will probably/hopefully average closer to 20mpg for the Thanksgiving day trip).

p.s.--Aside from shitty gas mileage and costly premium gas requirement, it's a great car that looks and rides like new despite the age and mileage. It's a not a car I would typically buy, but when I moved across the country four years ago, I needed an AWD car and this was my brother's "second car" (to be used on long trips so that he didn't have to stop to recharge his electric car), so he lent it to me. After a few months, it just made sense for me to buy it from him (for roughly half its blue book value).

p.p.s.--The irony is that I drove a Toyota Celica for most of my time in Los Angeles, a city where the streets are filled with BMW, Mercedes, Lexus, and the like; and now that I live in blue collar Pittsfield, MA, where everyone drives SUV crossovers, I'm the pretentious prick tooling around in the luxury sedan. So, in the eyes of others on the road...
I went from being a poor schmuck to a rich prick - ( New Window )