PerfectReign wrote:

>> just do not relize how much 87 holds things back because it limits
>> efficency and compression. The use advanced knock control to mask it but
>> it hurts MPG and power at times.
>
> Yeah, but it is certianly cheaper when you're filling up your 30-gallon
> tank at Costco for $2.41 as opposed to $2.85 for premium 89 octane.
>

For the sake of argument, lets say a small car - Saturn, perhaps - has
a 2.4l 170HP engine and gets 30MPG.

Then you put in a higher efficiency, higher compression motor - say 1.8l
170HP - that gets 38MPG, but requires premium fuel.

Then while I'm paying the extra 20 cents a gallon (the difference
between 87 & 91 octane here in St. Louis), I'm rewarded with higher MPG,
so it may actually be cheaper to use the higher octane / more efficient
combo.

smaller forced induction motors can and should replace larger
displacement NA engines, but consumers, insurance companies, and
manufacturers don't want it, don't understand it, and don't do it (in
that order).