hey ya'll, got a quick question. Why is it that the octane levels lower when you head into the mountains, say colorado, from texas? I know it's probably due to the lesser barometric pressure. Since it's better to run higher octane with a supercharger. but it runs like crap on that lower octane.

 

Your fuel injection and particularly the mass airflow sensor tells the computer how much oxygen is entering the engine and adjusts the ammount fuel accordingly. It is not recommended to use fuel less than 87 octane with fuel injection no matter what the altitude is.

I have a carbeurator on my truck and running 85 octane does not cause any problems.