Gas longevity? 455 miles and not one bar missing

last time I filled up was June 28th

 

I've kept fuel in a non-hybrid in the garage for six months with no apparent ill effects. THAT car would notice too (Mazda RX-7 3rd gen "slightly" modified). The Prius is much less fussy about the quality of the fuel. Pearl S sleeps with a full tank every winter for 4-6 months, and again, with no apparent ill effects.

 

Further to @Tideland Prius 's ideas: maybe just run through one tank without any charging every winter, ditto for summer? Run it just comfortably low, not near-empty.

 

Emission reasons aside, running a blend out of season isn't going to make much difference to a fuel injected engine. That said, I would use up the winter gas as soon as possible once it gets warm out. It contains fractions that will evaporate off quicker.

 

pip was 6 months, and i've never had a problem. if i had a prime, and it's 12 months, i'd go 12 months. toyota knows way better than i do, and they're pretty conservative.

 

Generally E10 tends to absorb water more readily than E0. Stabil fuel stabilizer is supposed to keep gas up to 2 years when added to fresh fuel.

 

Now don't be taking away Bob Wilson's fun!

 

Actually as I understand it, one of the ingredients of "Stabil" is ethyl alcohol. I suspect modern fuel is more stable than the older type without ethyl alcohol added. I know lots of people hate the E10 for various reasons, I ignore their reasons and like it for the benefits it gives (water in the fuel is taken care of, it seems to burn cleaner, and it smells nice when the car is first started).

For long term storage I would use the highest octane fuel with "up to 10% alcohol" I can find, so that any loss of octane rating will still leave me lots of safety. On small engines I drain the fuel and clear out the carburetor (by running the engine). I have had good luck with this strategy - I'm still running my 1976 lawnmower .

 

Ethanol is prone to "phase separation" due to water. Phase Separation = Water + E10

When you get past a threshold (which depends on the percentage of ethanol in the fuel and also the outside temperature), the ethanol fuel blend can't absorb any more water. But it (the ethanol) still wants to attract and hold onto more water. But now that it's past the limit for the blend, the ethanol is going to "fall out" of solution with the gasoline. Meaning that the ethanol "phase" separates from the gas "phase" and that's when you have "phase separation".

That site (& others) recommend a maximum of 90 days for E10.

 

They are also selling a fuel additive.

Modern car fuel tanks are well sealed. A lot less humidity is going to transfer into the tank for the ethanol to absorb than if the gas was in a lawnmower. And the only time I've seen phase separation in my lawnmower was when I added wet acetone to the gas. Most of the water in the E10 got there from the station tanks, which got in mostly as rain when the caps were off.

I won't worry about water and phase separation in a car. If you still are, use Iso-heet or 91% isopropanol in the tank.

Side note, Toyota is certifying 2018 models for E15.

 

Well, because of the longer drives I have when I work (and no place to re-charge) I can't get crazy numbers like 2,000... but I went around 700-800 miles and the gas bar still showed almost 1/2 tank (topped it off and it showed 6.4 gallons to refill to the top). So not bad. For the first 3 months of 2018, I'll be driving a 95-mile roundtrip commute 6 days a week (with no place to charge except at home each night) so it'll be interesting to see how many trips I can get out of a tank of gas (with about 25 of those 95 miles able to do on EV). And with my (non-charging) generally very low electricity usage at home, I should be able to do about 26-27 charges a month and still remain in the lower 16c/kw tier, and hopefully avoid the 24c middle tier.

 

Page 719 of owners manual says you can use up to 15% ethanol. Most small engine lawn and yard machines use plastic tanks to hold gas. These are permeable as opposed to the steel tanks in cars and most use carburetors which are not sealed either to outside moisture.


Unsupervised!

 

I noticed our 2016 Camry gas cap says no E20 to E85, but that doesn't mean all their available models are E15 compatiable.

I just saw the 2018 announcement in an article. The only companies not going E15, at least totally, seem to be Subaru, Mercedes, and BMW.