[sawmein2]

I was wondering about the octane in fuel. The manual wants us to use 93 octane. But what about a higher number. Like maybe 110. I remember back in the day, Sunoco 260. It had an Octane of 100. I've heard of folks heading to the local airport for Avgas. With numbers of 110,112 even 115 out there, is there an advantage to use the higher number octane or is the proformance maxout with the 93?

[gmcvt]

Higher octane itself doesn't make more power but allows you to run a more aggressive timing curve. Which is beneficial to the point that you achieve more power. This can vary depending engine component combinations. But, in general and within reason, yes, higher octane will give you the ability to make more power. To really take advantage of this, a good tune is necessary. The octane issue is why a percentage of people switch to E85. There is a bit more to this as it relates to the properties of different fuels that are higher in octane but I am just addressing the octane question itself.

[sawmein2]

So to really get the benefit of the higher octane a tune would be needed. I've added octane booster to 91 octane. Thats plus 3 on top of the 91. Seems to make a difference. At least by the seat of the pants. How about John 3:16

[gmcvt]

The issue is that pump gas can vary in quality. What is advertised as a given octane rating may very well not be what ultimately ends up in your tank. It could be that your octane boost is overcoming the shortcoming of the pump gas and would explain why you felt a difference. Your PCM has a timing curve that has a max permissable timing advance that is hinged partially on knock sensors. If the fuel in the tank isn't up to standards, it will produce "spark knock" and the PCM will not allow the full timing advance to be achieved to protect the engine.

A tune will add a more aggressive timing curve and as long as the fuel is up to the task, you will achieve a greater amount of advance safely. Even the tune, however, in general, will still be subject to the knock sensor, pending the tuners parameters. As it should be.

(Oh and John 3:16? Excellent support and continuity with John 14:6)

[ssmofo]

Avgas is very dry fuel and not made made for modern cars.

[95 imp]

You definitely want to run a higher octane in these motors than 91/93. The PCM will adjust to the higher octane fuel to the point of max advance in the tables.

The main problem is the CR. 11.5/1 doesn't like 91/93 and if it weren't for the computer, aluminum heads/block, and piston oil squirters, these motors would all be wrecked in 2 weeks.

The reason why these cars love the E is the 107 octane. The problem with E is lousy mileage and you need to get more fuel to the injectors.

Keep bumping up the octane until you're knock sensors stop picking up noise.

[Markoz28]

Run about 4 ounces of boostane in every fill up and octane will be around 95-96. Won’t gain any power but won’t lose any either. Keep engine from knock and the car will run smooth the whole time.