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Octane – the Magic Bullet

There have been rumblings about automakers suggesting that the octane in the gasoline be raised at the pumps. They claim it is in response to the 2025 U.S. government’s tentative mandate of 54.5 mpg required across entire fleets. I must admit that this is a pretty daunting task to undertake seeing a road filled with SUVs and trucks. I have no problem with ample sized vehicles on the road. That is the beauty of living in America; we live and dream BIG! Plus, I have never seen a Prius hauling a trailer loaded with a skid of bricks behind it. To meet those goals with large vehicles, that consumers want, the industry has an uphill battle.


With the advent of fuel injection, engineers have been able to fine tune fuel-efficiency. The evolving engineering of the heads and intake flow characteristics combined with sophisticated microprocessors have made it possible to bump compression ratios to numbers once thought only possible in race-specific automobiles. Engineers have the opportunity to do their “voodoo” on new technologically superior engines and reap more efficiency and power. By increasing octane levels they can tweak the formula even further in their quest to hit the Government’s 2025 fuel efficiency goals.

In theory this sounds like a great proposition; better efficiency, less pollution, possibly more power, and we can go to bed at night feeling warm and fuzzy doing our part saving the environment. Unfortunately, with a rise in octane there will be a rise in costs at the pump. There is no free lunch in this deal. So what octane number are we talking here? While searching online, the general consensus is the octane number that the industry is shooting for seems to float around 95. Seeing our average “regular” octane is rated at 87 (I have even seen 85 octane in some of my travels) that is a pretty lofty undertaking. From what I have read, the process of refining relies a lot on mixing different grades to get an octane average. It is only logical to assume there is less of the higher-octane stock rendered in the process, which in turn will dictate a higher price. There is no way to escape the invisible hand of economics.

All of this is well and good, but what does this mean to us as old car hobbyists? Aside from the increased cost of daily driving, there might be an upside to this rise at the pump. Unless we are dealing with pre-war and 70s-80s smog-choked, low compression collectors, we can breath a little easier while behind the wheel without worrying as much about hearing the dreaded knocking in our engines.

Octane rates were not always as meager as they are today. Prior to the 1950s the majority of cars did not require higher octane and octane numbers hung around 80. The Post-War era came about and the horsepower war started to pick up steam, which coincided with engine compression ratios climbing. The demand for higher octane met the market and offerings in the late 50’s were around 90 octane for standard and 98-99 octane for premium. The numbers kept inching upward as premium hovered around 100 octane - give or take a point or two. At this time compact cars entered into the mix and did not require the higher octane. The result was a wide array of octane ratios to fill the needs of the tiniest fuel sipping compacts to performance based vehicles to full sized land-cruising Cadillacs. With the octane rich properties of lead, it was easier to achieve higher levels of octane in the mix.

The Clean Air Act of 1970 started the end for lead additives and effectively squashed the horsepower wars. Smog equipment and low compression engines followed suit and the octane numbers began to fall. Unleaded fuel started to become the norm until leaded gas was completely banned in an amendment to the Clean Air Act in 1990. By that time leaded fuel was a relic of a bygone era. This meant that the older, high-compression engines of decades past not only had to deal with unleaded gas wreaking havoc on their valve seats; they had to tune their engines for the lower octane too. Threat of engine damaging detonation was now a reality.

If the octane is increased to aid in stricter governmental environmental guidelines we will once again have the opportunity to feel a bit safer with the fuel we put into our classics. I am sure there is a lot that is going to happen between now and 2025, and the major players in the game will have to work many issues out. In the meantime we can take solace in the thought of a silver lining to this foreboding cloud. Better fuel with higher octane ratings will assist us in keeping our classics on the road for some time to come. Perhaps the lack of fear over “pinging” will make the ride even that much more enjoyable.


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