what gas to use?

[blk_celi]

i have a 2000 celica gts and i have always been using octane 91... but i was wondering can i go with octane 89? please explain

[2way]

Stick w/91+. The compression ratio of the 2ZZ warrants 91+.

Supposedly, the timing on the 2ZZ will adjust for 91

[marc]

gas mileage will also decrease by going lower than 91.

[yotaceli]

i only saw my gas mileage go down when i tried 89, no lack in performance though.