Octane Question

[03NHVW]

OK, this probably has been discussed before so I'm guessing the answer is right there in front of me, but here goes;
Can different octanes of gas be mixed?
My VDub actually runs best on 91.
My most convenient stations sell 91 and 93, both for the same $$$.
What if I mixed Station B's 93 and 89 octane for an average of 91? and a cheaper overall tank? Is that useable or do they not mix?

Also, I know that the savings are hardly worth the time it would take to make two separate transactions, but still I've been considering it.
Thanks!

[busypaws]

yes mix away. I suspect that the 93 octane for the same price of the 91 octane is because the 93 has ethanol and the 91 is pure gas. Lots of other threads here discussing pros/cons of 10% ethanol mixture vs. pure gas. Search away.

[03NHVW]

Thanks for replying busypaws.
If I'm not mistaken (and I could be), I believe neither is pure gas.

I don't know if you're familiar but the 91 station is Irving and the 93 is Mobil (if it makes a difference). My feeling is that since the car only "needs" 91 I typically hit the Irving, but I like to get gas in the morning and that station is on the opposite side of the highway, causing me a few minutes of idle time while I wait for traffic to pass while I'm pulling in/out. In their favor, their employees are nicer though.

[mcrews]

yep you can mix.

[MPGranger]

It is my understanding that gas stations have two master gas tanks, even though they offer three grades. So the middle gas grade is actually a mix of the lower master and the higher master already.

Also Mobil is a Top Tier Gasoline station. Top Tier is a nonGovernment regulated fuel additive initiative, they claim there gas additives are better than generic gas. I haven't seen any independent testing, to say yea or nay on the subject; but that is why the top tier gas stations will typically be more expensive than normal.

[gone-ot]

...more "Top Tier" info here: Top Tier Gasoline

[rattroddrebel]

Me personally i had been using Casey's E10 because it was cheaper than the regular stuff. Since then I switched to Shell 87 because it claims to have more detergents to clean the engine better, but costs a few cents more. Wow a noticeable difference in mileage is what I was seeing in distance. Of course the persons running the cash register cannot give you any information on what additives they put in 91 octane to make it better than 87. My little car is great on gas, but going from around 32mpg to 40 just by switching fuel types, even with this car it was bitten by the hypermiling bug. I am always running late to work since I open the doors in the morning, this time I filled up all the way with the Shell lowest grade and a bottle of Amsoil fuel injector cleaner that boasts up to 5.75% better fuel mileage over 4000 miles. Since I put about 60 on the car a day it shouldn't take long to see results. But it is 20 in the morning and 50-55 degrees in the hours I would drive home. I know that temperature is a factor in the winter for economy, but I was trying to come up with a way to introduce warmer air into the airbox that feeds the engine. Since my 1993 ford festiva has a Vane Airflow Meter, any cold air kit or something like that is a real pain to get around. I figured I could run a pipe off of the exhaust, or some kind of engine coolant driven coil that would send ambient temperatures in to the airbox, to trick it into thinking its warmer outside. I have already converted it to Amsoil Signature Series 25000 mile oil, so I cannot wait to share my findings, at least before I convert this car to Smart car wheelbase, or the Peel P-50 size of car. Alot of my customers get the cheapest ethanol based fuel and complain of runnability issues in the cold mornings, unsure of this fuel's water content, but BE ADVISED, ethanol fuels are bad for small engines, mowers, weed eaters, I had a terrible experience this summer with that gasoline and dumped almost every tank because it just wouldn't start. I neglected to mention that I started driving 55 only on the highway. I will tell you there is a big difference between 55 and 75 when you live 25 miles from work. It definitely seems like you are going in slow motion.

[D.O.G.]

In the mid 1970's, my local BP servo had bowsers that let you select your own mix.
From Standard, 25%, 50%, 75%, to Super, all leaded petrol.

If I remember correctly, my Humber Hawk used 25%.

While I haven't seen that type of bowser since then, I'm quite sure that you can still mix your own special brew if you think it's worth while.

[rattroddrebel]

Yeah they dont have that in kansas. But I never considered the mix, I will have to see if the stations could do that, or get some gas cans to top off with a different grade to save money.