Low Octane Gasoline
 

The grade below 87. Can the Scions run on it?

Your car should be fine, go for it.

If the octane is too low, the engine will retard the timing. But if it bad quality, then you have to buy a little bottle of octane booster or fuel injector cleaner to fix it.

never use any thing under 87 octane, i my self use 90 octane cause its 10 cents cheaper then 87 octane... your owners manual tells you that

octane rating is ONLY a resistance to detonation.
the higher the rating the more resistant it is.
it has nothing to do with performence.

the need for resistance comes into play when you have a higher compretion ratio, and or forced induction .

The higher octane gasoline usually has more additives (cleaners) also, which can be bad or good. I know some engines don't react well to higher octane gasoline.

You can actually buy gas under 87 octane?

Yeah and it is like 30 cents cheaper. They sell it in most major cities. 85 grade.
Right now its $2.65 a gallon and I deliver pizzas so I need the cheapest alternative that I can find!
Someone HAS to have a definite answer for this!

just try it and see what happens.
your car will run on it.
run your tank alll the way down, then get a small amount like 2 gallons.
if it seem to run fine then go with it if not then go fill up with 87.
its not going to kill your car

i'd use 85 octane in small motors like lawn mowers

I wouldn't do it. It probably wouldn't damage the engine but you should notice a decrease in power.

If you look at the specs for the different model year xBs, you'll see the power ratings dropped from 108 hp and 105 ft-lbs (2004, 2005) to 103 HP and 101 ft-lbs (2006). As I understand it, the rating change was purely from a requirement that the engine specs are using the recommended octane rather than a higher octane gasoline.

thats why i run 91 when i can, i can notice a diff, not in power, but in all around engine performance. my car drops off in the top end before redline if im not running 91, it just flatlines sorta. and if a car is rated for a certain fuel running higher wont hurt it, but running lower will hurt it in the beginning, reset your ecu before you switch to the differnt fuel so your running bad on those 2 gallons you put in becuase the ecu's still trying to run with the higher octane, the ecu doesnt learn instantly, it takes awhile, and im pretty sure that any who says otherwise, is probabaly wrong, but if someone can come up with hard evidence saying otherwise, ill have learned something new lol

I wouldn't go any lower than 87.

One of my buddies worked on a 4 cylinder Pontiac Grand Am and after checking the timing and running many diagonstic tests he found that the only problem was that the driver put 91 octane in the gas tank. It made her knock sensor go crazy and her vehicle ran like poo.

octane rating is "ONLY" a resistance to detonation.
the higher the rating the more resistant it is.
it has nothing to do with performence. detonation or "knock" is gas exploding from heat and pressure without a spark.
big time bad news in a gas engine and your ECU will try to correct it by advancing or retading the timming because it thinks thats the problem. a higher octane rating doesn't mean the gas explodes with more force or more power. its not a peformance rating.
every motor will behave slitly different, if you realy think your motor runs better on a higher octane and have your own data to back it up then your engine is running slightly different then the next guy.
for example the 2006 scion xb has 103 HP, but thats only the average. if you were to test evey engine comeing off the factory floor you would see a range of + or - 5 to 6hp
even more in bigger engines.

the need for resistance comes into play when you have a higher compretion ratio, and or forced induction . this is why guys with turbos have AFC and pay close attention to knock.

Those are not good answers. The engine is already retarding timing on high load conditions with 87 octane. Lower than 87 octane, it cannot retard any more and the engine will knock.
1
The Owners Manual, Section 2, Page 114 says:
OCTANE RATING
Select Octane Rating 87... or higher.
Use of unleaded gasoline with an octane rating or research octane number lower than (87 octane) stated above will cause persistent heavy knocking. If it is severe, this will lead to engine damage.
2
The "quality" of gas is not related to its octane.

^final awnswer! right from the owners manual, that answers the original posters question.

as far as the 108HP rating dropping to 103HP, i believe there was a change in standards for measuring power, resulting in a slight drop for many different cars on the market. the 108 and 103 engines are actually equal in power

thank you

3mm, duno why the high octane would make your knock sensor go nuts. vintage what you said would explain why my engine drops off in the upper range when im running 87 octane, becuase the engine is retarding in the upper range more than it would have to when running higher octane, am i right? theirs nothing wrong with running a higher octane, just dont run a lower one, listen to everyone lol. if you want to run cheap gas, go buy a 50cc scooter, a leather vest, torn jeans, and a pink peanut helmet. rofl.

I dunno why it made the engine go nuts either, but I know as soon as she started putting in the 87 octane the engine purred like a kitten. Well, as much purring that a 4 cylinder GM motor can do before all the cheaply made brackets and plastic parts start falling off. lol.

lol, thats funny. my motor runs just fine on 91 lol, i have in their most time cuz i bottle feed my car