[anarchyx34]

A lot of people seem to think that putting premium fuel in their nonturbos adds horsepower. Here's the scoop.

Putting premium in an LX dosent do anything. Mainly due to the LX's lack of a knock control system, meaning it cant detect the higher octane fuel and adjust the ignition timing accordingly. Believe it or not, the higher the octane rating, the more resistant fuel is to burning. The reason this is beneficial, is that you can run higher compression and a more advanced ignition timing without running into the problem of detionation. That's where the additional power comes in. But the fuel itself makes no difference whatsoever. In fact, on my LX it seemed the car was a little more responsive with 87 octane fuel, than with 93.

On some high mileage cars, the use of premium will reduce knock, but that's just masking a problem the car already has. Usually carbon deposits are the culprit here, either by raising the compression ratio a little bit, or by causing hot-spots in the combustion chamber that lights off low-octane fuel too quickly. The premium fuel dosent burn as easily and dosent get lit-off from a hot carbon deposit as easily.

Now premium fuel on a GT is beneficial, since the GT runs high compression (due to the turbo) and has a knock control system and knows to take advantage of the added burn resistance of the fuel (usually by turning up the boost and modifying the ignition advance curve).

But anyway, the fuel isnt "richer" nor more healthy and not any cleaner either. If the motor calls for regular, use regular, otherwise you're just wasting your money.

Anyway, hope this helps some of you understand how it works.