Rolling back the octane
Friday, October 31st, 2008I have contemplated the tradeoffs of running lower octane fuel in my cars for several years, but the recent bounce in gas prices incentivized me to try it. My SAAB 9-5 owners manual recommends mid-range (the only car I have ever encountered that goes for the mid-range) and my Audi A6 recommends premium, and of course my Mini S JCW also recommends premium.
So this summer I have run regular octane fuel in both the SAAB and the Audi (can’t bring myself to do it in the Mini). I have been able to detect nether a performance or a mileage penalty. Combined mileage on regular gas over the summer was about 8K miles. In particular, I run a back roads route to western New York from DC with some regularity and I hammer it on the back roads (mostly driving the SAAB). I seemed to have the same ability to pass on two lane roads as I previously had on the mid-grade. Admittedly, neither of these cars are high performance, but I do want to and expect to run at high rates.
Car mags, notably Road & Track have begun to mention running performance cars on lower octane fuel, and the numbers they quote for horsepower loss are pretty modest. There is also plenty of mention of the fact that you do not risk damage to the engine (this is for modern, electronialy managed engines only). So my conclusion is that I will save the octane for the car I really like to wring out and bite the bullet on the others. Maybe I can even plow the gas cost savings into investment in my next fun car.
I do remember the old days (60’s) when my buddy, Bill T., and I were running high performance Corvette’s (that we both still own). Super premium and even octane boosters were the rule of the day. I recall Bill even found a source for higher test (104, I believe) aviation fuel at the local airport and hauled it to his Vette by the 5 gallon can in order to extract that last bit of performance. Of course, back then, lack of electronic knock sensors mandated that you run what it took if you wanted to avoid grenade-ing the engine.
So, my bottom line is: Unless you are running at the track, or are always intent on extracting that last bit of performance from your wheels, run regular





