87 versus 92 octane
 

I made the mistake of putting 87 octane in the tank yesterday. My Box is running just fine. So now I'm wondering, what are the tradeoffs using 87 versus 92 octane? If there are none, I'll just keep buying the cheap stuff. Thanks!

I believe the ECU will cut back on the timing advance when it senses knock caused by the lower octane fuel and you will lose some horsepower.

My understanding is you loose a few hp, and you lose a few mpg, otherwise it will run fine. The mechanic that explained it to me figured it was actually cheaper to use premium as the difference in price didn't save any money once you figure in the lower miles per gallon.

I had that 3000 rpm vibration in my 2000. Had my engine mounts replaced and it did nothing. The biggest Porsche dealer in Canada said it would need an engine rebuild and to put up with the vibration. My Canadian manual specifies 93 octane but 91 can be used. All but one station has a maximum of 91 octane. I'm the second owner and sure the car always used a maximum of 91. Six months ago I started using 94 octane exclusivly, from one brand that offers it. That 3000rpm vibration is gone. I'm thrilled!!!

It probably costs less than $5 more to fill with premium. If you can't afford $5, can you really afford a Porsche?

I agree with this, not to mention how much more efficently the car runs.