[Traidmarx]

so i've owned my car for close to a year now and i've always ran 93 octane in the car. when the dizzy was changed the timing was set back to stock 10* well yesterday i was about outta gas so i made a stop at a station that happened to be outta 93 but i needed some so i just filled it up with 89 octane. car ran the same as always yesterday but today...since its probably diluted all the 93 octane left. the car seems to be running waaaay stronger...could this be true or am i just imagining things??

[rlpiii]

i doubt that lower octane equals higher performance. if that were true drag cars would be running 89 octane instead of the 115 high octane race fuel.

[Traidmarx]

yes smart ass....i am fully aware of that i was asking in my specfic situation seeing as how my car is light years from a drag car

[JBIGBOOTSY]

Originally Posted by Traidmarx so i've owned my car for close to a year now and i've always ran 93 octane in the car. when the dizzy was changed the timing was set back to stock 10* well yesterday i was about outta gas so i made a stop at a station that happened to be outta 93 but i needed some so i just filled it up with 89 octane. car ran the same as always yesterday but today...since its probably diluted all the 93 octane left. the car seems to be running waaaay stronger...could this be true or am i just imagining things??

it shouldnt be noticeable. but the higher the octane, the lower the caloric value it has.

[jessemachone]

there is more fuel in the lower octane stuff. higher octane has more chemicals in it to prevent detonation so yes, there is more energy to be derived from lower octane fuel if your car doesn't knock on it.

[Lind]

lower octane fuels wont burn as long when fired in the chamber, higher octane fuels burn longer in the chamber giving you a more power per injection (dont really know how to say it LOL) but you get more combustion power from the higher octane per same about of fuel * im cant remember 100 percent but i think thats pretty close if not im sure someone will correct me

[Iwannagofast]

Originally Posted by Lind lower octane fuels wont burn as long when fired in the chamber, higher octane fuels burn longer in the chamber giving you a more power per injection (dont really know how to say it LOL) but you get more combustion power from the higher octane per same about of fuel * im cant remember 100 percent but i think thats pretty close if not im sure someone will correct me

you dont benefit from that tho unless you have the timing to match

[Traidmarx]

which is the reason i asked thanks....im not dumb i understand how combustion works....and if my timing was still set at 14* im guessing that the 93 octane would be necessary to prevent knocking and pinging but i asked since my timing is at 10* could 93 be too much octane for the amount of timing in the motor and that be the reason why the lower octane feels to run a lil stronger?

[Iwannagofast]

you definitely dont need the extra octane but i really dont think you would notice a gain from backing down....maybe it was just a colder day or something?

[95StangMX]

was it cooler and dryer weather than normal? My car and especially my truck which is turbo runs like a raped ape when the weather is cold and dry which is only like 1 day per year here....LOL

Edit: Iwanna beat me to it

[93hatch]

at 14 degrees you can get away with 91 octane

[Traidmarx]

no the temp has been no different than its been for the past month or so...

[rodeheavers]

i really cant see a difference from 89-93 in my car(on motor), but if i run 110, it runs like crap... the 110 burns way to slow for an 8.5:1 motor, i think stock 5.0s and 4.6s are in the 8.9:1 range, 89 would be ok for slower timing, but i would jump to 93 if you want to crank the timing up..

[White Thunder]

maybe its just responding better to the 10 degrees vice the 14......

[Notcho]

An octane rating is basically a fuel's resistance to detonation. The higher the number, the more resistant to detonation it is.

Higher octane fuel burns SLOWER than low octane fuels. Detonation is essentially the combustion of fuel BEFORE the piston gets to the top of its stroke. The piston is forced back down before it gets to the top, hence the lack of power and 'ping' sound. The 'ping' you hear is the low grade fuel combusting too early, which hammers your pistons and rods back down... very hard on internal parts. At the other extreme, if you put too high of octane fuel, the fuel will combust when the piston is on its downstroke; too late. Just a waste of money and less power than you could have.

The ideal octane ratio for your engine depends on your timing, compression, and other specific engine configurations. You pretty much want to run as low of octane as you can without detonation.

[Lind]

i think i stated that above but you just when alot more in detail lol

[superbean]

Originally Posted by Iwannagofast you dont benefit from that tho unless you have the timing to match

Bingo.

However, I always run premimum just incase the dizzy were to move a bit or you go lean for a second at the track.. slow burning fuel is friendly fuel.

Little squirt of race gas never hurt anyone.

[haywood11]

Originally Posted by White Thunder maybe its just responding better to the 10 degrees vice the 14......

i would say this and in conjunction with your compression

[03SonicBoom]

Originally Posted by 89 5.0 LX An octane rating is basically a fuel's resistance to detonation. The higher the number, the more resistant to detonation it is. Higher octane fuel burns SLOWER than low octane fuels. Detonation is essentially the combustion of fuel BEFORE the piston gets to the top of its stroke. The piston is forced back down before it gets to the top, hence the lack of power and 'ping' sound. The 'ping' you hear is the low grade fuel combusting too early, which hammers your pistons and rods back down... very hard on internal parts. At the other extreme, if you put too high of octane fuel, the fuel will combust when the piston is on its downstroke; too late. Just a waste of money and less power than you could have. The ideal octane ratio for your engine depends on your timing, compression, and other specific engine configurations. You pretty much want to run as low of octane as you can without detonation.

From my understanding, the gasoline should combust when the spark plug is fired and not from compression. The timing of the spark plug should be set up correctly to ignite any fuel (low octane or high octane) at the proper time. If it's igniting too late then the timing is off.

[03_StangGuy]

Originally Posted by Lind lower octane fuels wont burn as long when fired in the chamber, higher octane fuels burn longer in the chamber giving you a more power per injection (dont really know how to say it LOL) but you get more combustion power from the higher octane per same about of fuel * im cant remember 100 percent but i think thats pretty close if not im sure someone will correct me

Theres so much more to it though, theres burn speed and flame propagation patterns that all affect as well. Each fuel brand will be different as each delivery possibly. Maybe that just works with your setup?