What fuel octane do you use?

[73440]

But it does smell nice! Especially the Oxygenated Racing Fuels .... smells like perfume to me! 

I often use VP leaded 110 in the Harley and love to sniff the gas cap while sitting at the light .

[cj]

91 in both ebodies (440 & 360)

[Racer57]

Octane is a knock deterrent and does nothing towards hp. Its common for people to think a higher octane gives more power due to high performance engines using it. But they are using it because of higher compression and/or timing that requires it.

Racing gasolines makeup is more than just octane.

[Cuda_mark]

I use 93 at the pump in my 1970 440 six and 396 chevelle but I store them and occasionally run with VP110 leaded. Love that smell...

[cudabob496]

Seems octane helps power in my 98 Escort. 89 Octane makes the car run better and
have more power than 87 Octane.

[MOPAR MITCH]

When choosing a octane, remember that your choice should be based upon need -- simply to avoid engine knock (pre-ignition/detonation -- worst killers of head gaskets... can also damage pistons/rings/rod bearings).  If you drive mildly, you can probably get away with lower octane, but if/when you drive aggressively putting the pedal-to-the-metal, and/or towing, etc, then upping the octane rating will be to your benefit so to avoid pre-ignition/detonation.     

[Bluemonster71RT]

Octane is a knock deterrent and does nothing towards hp. Its common for people to think a higher octane gives more power due to high performance engines using it. But they are using it because of higher compression and/or timing that requires it.

Racing gasolines makeup is more than just octane.

But like in my case it allows me to bump my timing up a little more and does give better use of power. Though it does not add extra power it allows you to use it more effectively.

[cudabob496]

Kinda confused here. If you run a higher octane, you can sometimes
increase timing advance, and therefor make more power. So higher octane
can help your engine make more power. On the new Dodge Demon, you add
about 40 hp by going to race gas.

[Racer57]

Octane is a knock deterrent and does nothing towards hp. Its common for people to think a higher octane gives more power due to high performance engines using it. But they are using it because of higher compression and/or timing that requires it.

Racing gasolines makeup is more than just octane.

But like in my case it allows me to bump my timing up a little more and does give better use of power. Though it does not add extra power it allows you to use it more effectively.

Kinda confused here. If you run a higher octane, you can sometimes
increase timing advance, and therefor make more power. So higher octane
can help your engine make more power. On the new Dodge Demon, you add
about 40 hp by going to race gas.

Your agreeing with what I said. 

[cudabob496]

Octane is a knock deterrent and does nothing towards hp. Its common for people to think a higher octane gives more power due to high performance engines using it. But they are using it because of higher compression and/or timing that requires it.

Racing gasolines makeup is more than just octane.

But like in my case it allows me to bump my timing up a little more and does give better use of power. Though it does not add extra power it allows you to use it more effectively.

Kinda confused here. If you run a higher octane, you can sometimes
increase timing advance, and therefor make more power. So higher octane
can help your engine make more power. On the new Dodge Demon, you add
about 40 hp by going to race gas.

Your agreeing with what I said. 

yes, but like I said, my 98 Escort only requires 87 Octane, but runs stronger on 89? Why is that?

[Chryco Psycho]

The computer in the escort is sensing knock on 87 & can adjust on 89 to give more power without damage

[cudabob496]

ok, so without sensing knock, computer will advance timing.
makes sense. So, wonder what it will feel like if I go 92 octane.
will try it.

[71-440]

93 Octane here. Higher Octane to decrease the chance of knocking and get the most power out of what your engine is capable of producing.
My '09 5.7 had knock sensors. if a knock or ping was detected it would adjust timing to stop it which would affect the power output the engine
was capable of producing. I ran 93 in that car also. I might add that those sensors are very sensitive. They can pick up a ping or knock that your ear can't detect.
Anyway that's what I learned in the 5 years I had that car talking to different engine builders.

[ToxicWolf]

I use 93 in all of our cars ... Even my wife's Prius.  I've been told that higher octain gas improves milage in all cars. 

[Racer57]

I use 93 in all of our cars ... Even my wife's Prius.  I've been told that higher octain gas improves milage in all cars. 

But does it increase the mileage enough to pay the additional expense of the fuel ?
Btw, on a Graveyard Cars episode when they fired up a '70 dual quad Hemi,  Mark Worman said "Everytime a dual quad Hemi starts, a Prius dies".