Need help selecting a fuel? Call the experts. | Fuel Tips

Sometimes you have to look deeper, explains Zachary J. Santner, technical specialist at Sunoco. He points toward Cyclone 17, a recent addition to the Sunoco Race Fuel lineup, as an example. 

This leaded race fuel is aimed at radical engines, packing 117 octane and no ethanol. On paper, however, it also looks a lot like the brand’s SR18, a leaded, ethanol-free product sporting a 118-octane rating. 

To see the difference, he continues, you have to look deeper. “Make sure you’re using the right fuel for your application,” Santner notes. In this case, that new Cyclone 17 was designed for a very specific application: drag racing–although perhaps it could benefit some autocrossers as well.

A lot of drag racers don’t fully warm up their engines before making a pass, Santner continues. Instead of launching a campaign to get drag racers to change driving styles, Sunoco instead worked with engine builders to create a fuel that better evaporates at colder engine temperatures. (That difference can be seen in the 50% evaporation temperatures found on the Sunoco Race Fuels website: 192 degrees Fahrenheit for Cyclone 17 and 209 degrees for SR18.)

The bigger take-home message for most of us here, though: It’s okay to consult engine builders or fuel suppliers regarding fuel choice, and Zachary reminds us that he’s just a phone call away at (800) RACE-GAS.

What does this graph show? Science. Particularly, it compares the evaporation rates of two Sunoco fuels: SR18 (blue curve) and Cyclone 17. While both fuels feature nearly the same octane rating, the evaporation rates show how one is better suited to making power in colder engines.