Does a V8 mean you have to run 93 Octane

well no you dont have to run 93 in a v8 i got a 78 f150 and i run 87 inless i am going to go play in the mud or pulling something, my dad has a 2003 f150 and he runs 87 in it all the time with no problems, the only reason you need to run a 93 or higher is if racing or if running a high compression engine or if you like to pay 2.10 plus for the good stuff

if your engine isnt set up for it it wont do you anygood. might actually hurt you more in the end.

No, it doesn't have anything to do with number of cylinders or engine size. It has more to do with compression ratio and/or tuning/timing.

what about if your running advanced timing. ive always heard you have to run 93 if you have your timing turned up. when i had it at base timing i ran 87 in it...but since i turned it up to 12* or 13* (buddy did it for me, dont know what its at really) ive been running 93. any insight to this?

ECU5.0 said:

what about if your running advanced timing. ive always heard you have to run 93 if you have your timing turned up. when i had it at base timing i ran 87 in it...but since i turned it up to 12* or 13* (buddy did it for me, dont know what its at really) ive been running 93. any insight to this?

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that is what others have said (more octane for more timing). you dont necessarily need higher octane (which equals slower burn). i run as much timing as i can on 87 octane (15* in winter, 12 in summer at over 100* ambient temps). if i ran more octane, i could likely bump a degree or two more. you gotta play with it. you can always back your timing down too (instead of buying higher octane gas).

HISSIN50 said:

that is what others have said (more octane for more timing). you dont necessarily need higher octane (which equals slower burn). i run as much timing as i can on 87 octane (15* in winter, 12 in summer at over 100* ambient temps). if i ran more octane, i could likely bump a degree or two more. you gotta play with it. you can always back your timing down too (instead of buying higher octane gas).

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yeah, im kinda thinkin im gonna do that the way gas is lookin right now. but im gonna try running like 89 or maybe 87 and see how that does

There was a whole debate on this before. I do not remember the exact details but all i remember is that running higher octane causes your fuel to last longer in the combustion chamber. AKA burn slower. This way your engine will not experience a lean condition. I have been running 8* timing with 87 octane until today. Car ran great. 200+ miles to the tank and was incredibly reliable. *car is almost stock*

There's not a one size fits all when it comes to knowing what combination of timing, compression can be run with what octane fuel. MANY, MANY variables are involved - combustion chamber design, use of the vehicle, ambient weather conditions, age/condition of the engine, head material, cooling system condition -- the list goes on and on.

There's no benefit to running any higher octane than you have to in order to support your set of variables. Most stock-headed 5.0's can get by with 12-14 degree timing and still run 87 without detonation. But if yours won't either up the octane, or cut back on the timing. What someone else's does may or may not be duplicated by yours. I have aluminum heads on mine - stock bottom end and mild cam; it runs with 16 initial timing, 32 degrees total in by 2800 rpm, and it runs on 87 octane without a hint of detonation. And, it seems to get about 1 mpg better mileage (city and highway) on 87 than on 93. Probably because the 87 octane fuel is ignited more easily and burns a bit more quickly than the 93. For cars with lots of timing and/or compression, the benefits of running the higher octane to avoid detonation outweigh the slower burning characteristics of the fuel.