I realize that we all start somewhere with our automotive knowledge, but I feel I gotta make something clear to everyone with the question of premium fuel. While pumping a few gallons of 100 octane unleaded up at Infineon Race way(Sears Point) there was a guy with an STi who was telling me 87 octane was all I needed because of the low compression of my motor. Now I run into another guy telling me the same thing. Where to start? for anyone not sure, put the premuim in and read a little something about internal combustion especially mit turbo. I feel alot of these misconceptions occur as gas prices go higher, and people hear alot of misinformation especially from people who never picked up a wrench in their lives. Thanks, I feel better now.

 

READ the OWNER's MANUAL
it states 91 is the MINIMUM and 93 is recommended, and since CA has **** for gas, 91 is all we have so pump that

 

THere are a lot of rumors, a coworker told me that every car in CA has to perform to it's factory spec on 87 octane. It sounded like BS but he is a pretty knowledgable guy, I still run 91 in my rex though.haha

 

u can run 87 octane in your car in case of an emergency (like if your car has no gas and the station has no premium fuel, and the next gas station is far away), but the manual states that if u do, only put as much as you need and drive it easy until u are able to put premium gas into it.

But to put 87 octane in and tracking the car is asking for trouble.

 

87 is pretty ****ty, 89 isn't bad but it totally sucks when it has ethanol added to it, therefore I run 91 octane in my N/A, it gives me better gas mileage plus a little kick when the gas pedal is floored.

 

I thought 87 was bad for N/A Suby's unless they are tuned or modded to run it? I had a 2008 forester sport 2.5x (N/A) before I got my rex and it didnt run as good with higher than 87 in it...

 

You car will run on 87, but it will pull timing. I wouldn't advise going it unless it's the only thing available and you can stay out of boost.