Probably true but that’s maybe a pint, less than 1% of my full 16-gallon tank.
What model is it? Just curious. I have an Infiniti Q60 with a 3.7L engine with 330hp and it only needs 91.
Here’s a trick – park near by and watch until someone buys 93 octane. Then swoop in after them and pump your 87. You’ll end up with 87.1 octane! Score!
Some years ago (like, in the 1960’s I think?) there was a brief trend of gas station pumps offering “Dial-an-Octane”. It might have just been a gimmick that one brand had. There was literally a dial on the face of the pump, that you could turn, to select your blend.
Okay, I found a pic on-line that somewhat resembles the blend selector that I remember. I don’t know what the numbers mean. Image is from this thread where people are talking about history of auto fuel. Lots of good discussion there on this topic, it seems. (ETA: At the bottom of the page, a list of other threads on similar topics.)
I checked out the pricing. Big jump from 87 to 89 (like $2.00 to $2.65), but only about another dime to go to 93. Hardly worth the effort.
Yes, with a “but”
I work in a gas station, and that is exactly how our pumps work. We have 2 storage tanks, one full of 87 and one full of 92. Buy regular and you get straight 87, buy premium you get straight 92, but if you buy “mid grade” the pump mixes the two together.
The “but” is that it is conceivable that two different sources of gasoline are using different octane boosters in their fuel, and those different chemicals may not mix the way you would expect.
But I would assume that commercial gas is engineered with consideration to what happens if you mix with a different grade from a different company, so you are probably only going to get those weird reactions in theoretical conditions.
Any car tuned to run on 93 U.S. octane for max performance, and wherein the manual/etc recommends premium only, it is absolutely tuned to run on 91 without engine issues. 93 would be best for performance, but requiring premium in the U.S. = 91 minimum. 93 can usually be optimized by the engine. 91 is often the only premium available.
That’s weird. There is an almost invariable 10 cent difference between 87 and 89 and 89 and 93 here.
Expensive! My car (2005 Pontiac Vibe GT) specifies 91 octane in the owner’s manual. I just paid $1.989 per gallon yesterday to fill up the tank, with regular selling for $1.789.
I have no idea what folks do with older cars that required 93 octane gas; that stuff is pretty much non-existent north of Portland, Maine.
Depends. What are you going to cook with it?
In the US, the octane number is the average of the Research and Motor Octane Numbers. This is the (R+M)/2 you see on the pump. But what does the octane number really mean? It measures how much the fuel can be compressed before igniting so a 93 octane gas can be compressed just like a mixture of 93% octane and 7% cetane
Two different octanes would then be the weighted average of the gallons purchased. So 7 gallons of 88 and 8 gallons of 93 gives you 7 x .88 + 8 x .93 = 13.6 “gallons of octane” out of 15 gallons of gas making it 90.7 octane.
Took 29 posts to get there
Up until a few years ago, that was the case here, too (in Chicago). Now, it varies a lot from station to station; it’s not uncommon to see a difference of 30c or more between each grade. Plus, very few stations advertise more than the “Regular” price on their sign, so you aren’t able to see the price for the higher grades until you get to the pump.
(My wife puts premium in her car, and complains about how big that gap has become.)