you were likely going uphill most of the way one way and downhill on the way back.

 

You need the higher octane gas....The engine is a high compression engine and low octane will cause detonation....Detonation is BAD!!!!!

 

O. K, I'm convinced. No more regular fuel. Back to the good stuff.
Thanks for the input.

 

your S thanks you.

 

Putting higher octane in cars that don't need it is pretty much useless (Modern cars that is).

That applies to the tC also.

 

As silly as it sounds, I miss 93 octane. only 91 in my area now

 

Actually, this was proved not so in a test by car and driver. I forgot the link to the results, but it was posted in another thread with the same question.

The main thing is the ECU. There is a chance that your car can benefit from premium, especially if it's a newer car. Research showed that just like ECU's that retard timing to make up for detonation, some ECU will advance timing to make up for higher octane fuels giving the engine more power. Of course this was not the case in all cars and especially not in the older ones. However, some newer cars did see improved performance numbers with higher octane. It just depends on their ECU.

 

 

Think of it as a bank. The petrol co's pump XXX amount of fuel into the nationwide gas lines, they then remove XXX amount of fuel at said location, add their 'additives' and raise octane levels, etc then truck it to their individual stations. The only exception to this is Chevron, which uses their own fuel lines.

 

Premium fuel IS NOT necessary if you are an old lady and driving your S likes a Civic.

Premium fuel IS necessary if you are driving it as it is intended to be driven.