I have two vehicles that are sensitive to fuel octane levels (both with small tanks). I have always wondered how much of the junk gas from the last selection flows into my tank before the high dollar stuff makes it out of the nozzle. My turbo is computerized and will adjust(de-tune) for detination but my Triumph depends on me to hear it and back off the throttle. I usualy look for a pump that had super as the last product delivered but the higher gas prices brings out the tightwads from what I have observed, many times I cant find one.
Few cars can detect the difference between 87 and 92 octane…The amount of fuel in the plumbing will have NO EFFECT on your overall purchase as long as you buy more than a gallon…There is maybe a quart of “last purchase” gas in the hose. Worry about something else…
I agree with Caddyman. Mixed in with 14 or so gallons of 92 octane, the amount of 87 octane that’s in the hose from the last fella wouldn’t have any measureable impact whatsoever on your 92 octane. If the hose is 8 feet long with a 3/4" ID, the total volume in the hose is only .31 gallons.
It won’t change the octane to septane. The car could run on 91 sextane but it would be a little distracted. The car will definitely not see the one quart difference in fuel grade. If you don’t buy gasoline a quart at a time, you should think about something else. If you can’t afford to send one of your employees to get your gasoline, you really do have other things to worry about. Some people worry that the government may be putting mind control agents into airplane fuel so that we all get a dose. Other people worry about meeting those people.
If it really bothers you, get a gas can and every time you fill up put the first quart in the can.
I doubt it’s even a quart of the wrong stuff you get. Next time you fill up try this. After the pump shuts off, flip the lever or push in the little flap to shut off the gas pump and then pull the nozzle out a little and pull the trigger. The amount that comes out will be the total amount of gas between the individual product valve and the nozzle and I’ll bet it’ll be less than a cup.
There really is very little gas in those hoses. Gas stations years ago had pumps that would pull any gas in those hoses back into the tank. The reason was people would siphon the gas from the hoses at night when the station was closed. Before they put the reverse pumps in there those hoses could hold a quart or more.