Premium?

[SoK]

how has the quality of 87 octane fuel changes since 1997?

if porsche recommended 91 minimum in 1997, would that equate to 2012's 87 octane?

[Overdrive]

That is extremely doubtful, Sok. And for that matter, with the inclusion of ethanol in a lot of today's fuel, it's even less likely that today's 91 is up to the task of minimum duty for the engine. In an emergency, you put whatever is available in your tank, shy of dieself fuel, but simply put: these cars were not meant to save us money at the pump.

Always use the highest octane available when it is available. At no time should one be putting a different octane fuel in the car when the recommended is available. That's basically what is in the owner's manual, which trumps any other arguments. If it's not meant to be used, it's not in the owner's manual.

[SoK]

I only use 93 with NO ethanol added; I luckily have a Shell station a mile or so away that does not include it.

But what you're saying is that the quality of 93 or 87 gas hasn't changed in 16 years (being that a 97 Boster came out in 96)? I'd figure quality standards would have increased since then. Just curious, not recommending using lower-grade gas.

[2003S]

Originally Posted by SoK

how has the quality of 87 octane fuel changes since 1997?

if porsche recommended 91 minimum in 1997, would that equate to 2012's 87 octane?

Since octane is a measure of compressibility before ignition, I would seriously doubt a material change. 87 octane in any year ignites at lower compression than 91 octane.

Higher compression engines require higher octane fuel, or bad things start to happen.