Is Yesterday's Gasoline Superior?

• Staff Writer @ Classic Motorsports
• 29-Jan-22
• View source article

 

Back in the day, pump fuel was just meaner. It had higher octane, the lead craved by the day’s engines, and a smell that meant business. Everything was better then, right?

Sunoco even operated its Custom-Blended pumps from 1958 through 1972, allowing customers to choose the octane their engine needed. Eight grades were offered, ranging from Sunoco 190 all the way to Sunoco 260, billed as the highest-octane fuel available–one good enough for championship driver Mark Donohue.

Not sure how much octane you needed? Sunoco stations offered a chart that provided recommendations based on year, model and engine. If you had a 1967 Camaro with the inline-six or standard V8, for example, Sunoco recommended 200, a regular-grade product. If you’d ordered the high-performance V8, Sunoco said to consider Sunoco 250, billed as a super-grade fuel.

 

But what about octane numbers? As explained by Zachary Santner, senior quality specialist at Sunoco, stations didn’t have to post octane ratings until September 1973. Sunoco 190, the economy-grade fuel, sported an octane rating of 87, while 260 checked in at 97.5.

While such high octanes may no longer be offered at the corner station–the lead that easily added octane was removed from street fuels long ago due to its dangerous effects on human health–Santner argues that today’s fuels are actually a better product.

Removing lead while reducing the sulfur and benzene content allows modern fuels to be less hazardous for humans and the environment. Today’s oxygenates, such as ethanol, help boost octane ratings without the use of lead.

Modern gasoline also contains better additives than fuel from the past. “Detergents help the engine remain like it was new, while antioxidants help fight the formation of gums and varnish,” Santner says, adding that minimum detergent requirements started in 1996 due to an EPA mandate.

And if you’re looking to go above the minimum, Santner offers some advice. Top Tier fuels, like Sunoco’s pump products, contain more detergents than the minimum level, while Sunoco 260 GT is an unleaded, 100-octane product that can be blended with pump fuel to produce the desired octane. (And for those living in states that follow CARB regulations, Sunoco offers the similar SS 100.)