Octane blending? 89+93=91?

[Joe Rampino]

With the cost of fuel, I'm looking to save in any way I can. My wife's Audi requires a minimum of 91 octane. I usually try to find a Sunoco that has 91, but if I can't, we end up going for the high price 93 from one of the other stations around here that offer 87, 89, & 93. I usually fill up at half a tank. So if I alternate every other half tankful between 89 & 93, will that average 91?

 

[Jim Austin 2]

Yes! That is exactly how you get your mid range fuel at the pump delivered by the trucking company. They mix the high grade and the low grade as it's filling the delivery truck at the terminal to make the mid grade. I should know!

 

[RJ McD]

Alternating every half tank 89/93 will give you a blended octaine level but not exactly 91. It will vary from roughly 90 after one fill to 92 on after the next. That may be close enough.

If not , you can maintain the 91 level if you know how much gas you need. Fill half of that amount with 89 and half with 93 octane. So if you need 10 gallons, fill with 5 gallons of 89 and 5 gallons of 93. It would mean you need to do each as a seperate tranaction at the pump.

 

[EddieS'04]

Rampo, I dont know what your wife drives. You might do some research and find it as many of the cars nowdays, have knock sensors. This will alow you to save money and run a lower grade of fuel octane. You will give up some performance. The knock sensor will pull the timing back where you wont ruin the engine...

 

[Kevin Lang]

What about those octane booster fuel additives that you're supposed to use when you can't find fuel of X octane? They're only 2-3 bucks at autozone and even walmart, which is, sadly less than a gallon of 89 gas.