not necessarily. even if the engine specifies 93, it won't gain hp/mpg UNLESS pinging actually occurs when using 87. this won't always/usually happen, unless you're driving hard, up steep hills, hot weather, etc. my saab specifies premium also; it's a bit different that it's low compression, but the turbo is much more likely to detonate than a streetable high compression engine. instead of retarding timing, it reduces turbo boost. so i can actually see when the computer kicks in by watching the boost gauge. surprisingly, this only occurs in extreme heat, a/c on, up steep hills, with the pedal floored. otherwise i always get full boost.
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Originally Posted by JackG
You're missing the point. If an engine is designed to use, and benefit, from 93, it will most definitely lose power when using 87. The engine management computer will detect pinging, and will retard timing, enrich the fuel mixture, etc. to stop the ping. It will be ping-free, but will be down on power and will use more fuel on 87.
Running 93 will gain you power in this case.
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