Originally posted by morbid:
Originally posted by Big Jim:

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Actually, I'm mildly disappoited that my car was factory tuned so that premium fuel is not that critical. I'm also disappointed that there has been so little equipment wise to enable me to tinker with the settings that I used to be able to do by hand.
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It must not get that hot in your part of CA because mid summer temperatures in Phoenix make it evident that 91 octane is NOT enough. Knock or ping... I don't know, but the car definetely looses power after making a predet type sound. 100 octane resolves this issue, but is expensive... auto parts octane booster sometimes helps, unless I'm doing lots of city street driving.

So how about this... if you live where it can reach 120 degrees, drive with the a/c on, rarely let the secondaries close, and don't have enough faith in the knock sensor to risk your engine, then you CANNOT run less than 91 octane.




Amen to that! I grew up most and spent most of my life in Tucson. It is hot there and hotter in Phoenix. I could never run less than 91 in AZ except maybe in the coldest part of winter (50F range )

Former owner of '99 CSVT - Silver #222/2760 356/334 wHP/TQ at 10psi on pump gas! See My Mods '05 Volvo S40 Turbo 5 AWD with 6spd, Passion Red '06 Mazda5 Touring, 5spd,MTX, Black