Thanks. I didn't know that (obviously, d'oh!)

 

Yes,,they are rated different,
I run our highest (93)US in any boosted car I drive
and I always carry a can of Torco racing octane booster
in my trunk in case on a trip I cant find 93.
Dont confuse cheap off the shelf octane boosters with the real thing,
they are much more expensive but all it takes is one bout of detonation to to severely damage your engine.
https://www.summitracing.com/parts/t...caAuPzEALw_wcB

 

You don't need avgas unless you are running 12:1 pistons and driving it to max rpms. You have a computer-controlled igition system that compensates for lower rated octanes.

 

They all come from the same tanks in the same tank farms.

 

I ran my turbo charged Eagle Talon with a bypass pipe in place of the cat. It was slower. Apparently, the turbo needed the back pressure from the cat. I put the cat back in.

 

When the throttle is mostly closed, high octane does nothing because the actual running compression pressure is reduced. But when throttles are wide open, the compression increases to it's max, and that's when the higher octane is beneficial in general.
Think of what happens when you stop up a vacuum cleaner. The motor revs up because there is no air to LOAD the pump. Kinda like a closed throttle valve lowers cylinder pressure.
When running compression pressures are higher coupled with hotter intake air, cylinder temps are higher, thus the octane requirements are higher. If the intake air temperature is higher as in a HOT summer day, cylinder temps will also be higher. So in other words, as long as full throttle and hot weather is avoided, lower octane is fine and does no harm. However, the knock sensor will HEAR pre-ignition due to lower than required octane being used and the timing is backed off automatically by the ECM.
Octane rating is the measurement of RESISTANCE to burn. Has little to do with the actual heat BTU's being produced, so it's misleading. With high compression, and hot air, low octane fuel causes pre ignition. This is what eventually breaks piston rings. Buy the fuel that matches your driving habits. Simple.