well in so cal the highest octane we get is 91. anyone use octane additives? which ones are recommended?

 

...since octane boosters don't boost octane enough to bring any benefit.
Octane "boosters" raise octane in numbers of "points". An octane point is only one tenth of an octane number, so these ones that advertise and incredible 5 point gain is really going from 91 to 91.5

Octane boosters are also very expensive - giving you a fractional increase for several dollars...

 

Why do you want to raise the octane of the fuel - Is your car knocking, pinging, detonating? - Running perpetually retarded?

 

we have 94 here in toronto.. but what's the difference really? 1-2hp more? for 10cents more..

 

No horsepower increase. Octane is a measure of a fuel's resistance to knock. It has absolutely nothing to do with power output unless your knock sensor is detecting the onset of knock & retarding timing. Power output is effected by the calorific value of the fuel - which is mainly influenced by density & only then if you are capable of completely combusting that fuel ideally within the stoichiometric range.

 

it doesn't make any differences to our cars. maybe if you have FI.

 

oo i see... because my friend chipped his car and said something about having 94oct will give yuo 1-2 more hp.. but thats only after the chip.. something about the ecu regonizing it is 94 or something.. no idea.. he drives a vw

 

Will only make a difference if he increased the compression ratio & the car has greater octane requirement. Any power gains from octane only are achieved by higher compression ratio & being able to run more advanced timing.

Increasing octane on a car that does not need it achieves nothing. The OP I presume has a standard/stock car.