Looking at a 02 and know it recommends premium, but what is the downfall of using 87 in place of 91? Just a performance loss or leading to serious damage.

 

Poor performance in the short term; in the long term, you might clog your catalytic convertors, cause engine knock, set your ECU into an extremely conservative mode and perhaps even damage engine seals. Gas is expensive, but probably cheaper than repairing your car in a year or two.

 

the detonation you will get on 87 will lead to premature engine failure.

 

Above quote from Shiv Pathak of Vishnu Performance Systems.

Don't try to save money at the pump by putting in low octane fuel. It will run so pig-rich that it will more than offset any savings you were hoping for. The WRX is not an economy car. Practicing smooth driving habits will help more than any tuning or add-on devices. Forget those 'snake oil' Tornado Fuel Saver devices - waste of money for a cutting blade from a food processor.

My 2002 MY WRX will average 22.5 mpg during a daily commute through fairly heavy rush hour traffic in both directions but I've managed to achieve a best figure of just over 30 mpg on the freeway while maintaining a steady state cruise of about 60 mph on level terrain.

--
0==WW==0
"…axles of evil…" - george w. bush

 

Thanks for the replies. That's what I thought.

 

While I was in alaska I could not get anything above 90 at the pump and I got 320 miles to a tank max.
Now in Virginia I get 93 at the pump and get 380-400 miles per tank.

It saves money for me to get the good stuff.

Also my car is running better after running 93 for a month now.