Here are a few facts from an Ex- Petroleum Bypass Engineer, for those of you who have also performed this job, you know what I mean.
Octane levels are regulated and are always calculated the same way, at the same tempurature. So, the Octain level will always be on the Yellow sticker. If you say you can't find the yellow sticker on the pump, only a white one? Go back to kindergarden and hang some drawings in the window.
Higher octane fuels are generally required for engines with higher (Normally asperate) compression ratio engines. The basic principle is that detonation will occur at a certain preasure, the higher the octain, the higher the preasure before it will detonate(or just spontaniously combust) like all those drummers from Spinal Tap.
Higher octane fuels have other charactoristics, they also tend to burn a little hotter, for all intense purposes. And they burn more controlled(slower).
By burning more controlled they tend to produce more energy more efficiently.
But, they do not always produce more overall energy than a lower octane fuel.
This starting to remind me of "who's on first"
Lets make this easier, SUMMARY:
changing the octain level of fuel you use in your car, changes the torque and horsepower performance curves.
Lower octain will generally give you slightly better bottom end, and higher octane will give you slightly better top end.
Each Manufacturer has tuned their engines and transmissions to match the designed performance curves using their recommended octane levels.
Change the octane = change in performance.
The SVX has a matched Transmission to motor ECU/TCU control system. So its best to use the recommended 91 octane for best performance.
If you have a manual transmission, then learn to use the octane level to your advantage. If you can't control the shift points in your transmission(automatics), then change where the engine hits its highest Torque by adjusting the octane. Go too low, and you get deiselling(detonation). Go too high, and the car shifts before the torque kicks in.
I hope this makes sense. I will admit I have simplified some of this info, but in general, it is correct. If by chance any-one see's a serious error I have commited, well....I'm sure you'll share it.
