Why fill up with a street-legal specialty fuel? | Fuel Tips

More Octane

While the pump fuel found at the corner store usually tops out at 93 octane–and maybe only 91 on the West Coast–260 GT and SS 100 carry a 100-octane rating. “It’s for those who want more,” Santner says, meaning more boost, more compression, more ignition. That octane rating won’t magically deliver more power, but it’ll allow tuners to safely configure an engine that can make more power than the typical factory setup.

While higher-octane options exist, Santner notes that this one is street legal and suited for those applications that are a bit spicier than stock–call it OEM-plus in today’s parlance. 

More Cleanliness

“It’s very stable,” Santner adds. Sunoco GT burns clean, carries Top Tier detergents, and contains much less gum and varnish than standard pump fuel. As a result, he explains, it has a long shelf life–more than a year when properly stored. 

More Consistency

The recipe for pump fuel can vary depending on season, location and refinery. Wintertime fuels, for example, have higher Reid vapor pressures to assist the starting process; conversely, summertime fuels have lower Reid vapor pressures to combat smog. Additionally, most pump fuels are labeled to contain up to 10% ethanol content, yet the exact percentage can vary. So, how do you tune to a moving target?

Sunoco 260 GT, Santner continues, always follows the same recipe: same vapor pressure, same ethanol content, same oxygen content, same everything.