I have a 2008 XKR with about 55000 miles showing. I live in Arizona during the months of Nov to April and in Colorado the remaining months of the year. So the car sits garaged for 7 months in AZ. I have read that ethanol fuel will deteriorate sitting in the tank for extended periods. The only ethanol free fuel available where I live in AZ is 87 octane. Can I run a tank full of low octane (87) fuel without damage to the engine? I will put fuel stabilizer in the tank during the idle period. Does anybody know of an octane booster that will really boost the octane and isn't a gimmick?
Thanks.
BD

 

It isn't octane that's the problem, it the alcohol that gets thick and gooey and can clog lines and passages.
Actually, lower octane fuel burns faster than high octane under identical situations. It's the pressure induced combustion with higher cylinder pressure that's the problem.
Your car's computer will detect any detonation and retard the timing, you will just get a minuscule reduction in performance running lower octane fuel.
For lawn equipment and other small engines with tiny fuel passages in carburetors fed by gravity, gummy alcohol fuels cause major problems. Your car will be fine for a year or more.

 

The boys on Roadkill bench tested a 600hp engine on all the octanes. Their conclusion is surprisingly, no difference. All the graphs were the same!

 

The reason for higher octane is to greatly advance the timing where low octane fuel would detonate. I didn't watch that particular roadkill, but I'd be interested in whether they tuned each fuel pull separately. More timing usually results in more power. Higher octane allows more timing.

 

In the segment they led everyone to believe that only 4 different fuels were used. Surprisingly the fuel with alcohol, cooled the mixture just before the burn.

 

Add a bottle of octane with your fills then. It’s cheap.

 

they run fine with 87 just don't go looking for trouble

 

87 octane fuel has a shorter shelf life than more refined, higher octane fuels. Also exposure to air reduces shelf life. You should fill the tank with premium before the car goes into hibernation.
https://www.sunoco.com/fuel-facts/po...ls-more-stable

 

I'd say this would be a good idea for storage of a couple years. In seven months the degradation difference would be minuscule.
By far the better idea would be to get alcohol-free fuel as the alcohol is corrosive and it gums up very fast.
If you can't get alcohol free fuel, you COULD make your own although working with a large quantity is fairly difficult. A couple gallons is easy though, using the Add Water method to adhere the alcohol to water, which is denser and can then easily be removed from the bottom of the entire mixture.
Troublesome, yes, and not really something I would bother doing. Seven months of storage is nothing to be concerned about.

 

Just use the fuel stabilizer and drive the car as often as you can. Alternatively, just enough non-ethanol fuel to get it to a gas station after hibernation. Plus the stabilizer.

 

One reason not to use a low octane with alcohol during storage is that, the gas has a very low octane that is increased by mixing the alcohol, having a higher octane. Lets say, it now goes up to 87! But in storage they separate, and the cheap low octane is on the bottom of the tank and is pumped first to the injectors. Until the car moves and mixes the fuel, you would be in the low 80s....