By Stefan Kristensen
August 4, 2022

What Kind of Fuel Does NASCAR Use?

NASCAR has had a long history of entertaining fans with the skill of the drivers and the incredibly designed cars. One interesting little-known fact about NASCAR is the type of fuel that the racers use.

Sunoco Green E15 is the race fuel used by all NASCAR series vehicles. A blend of unleaded gasoline and 15% ethanol, Sunoco has a greenish hue.

There’s a lot of interesting history behind the origin of the most widely used racing fuel for NASCAR. The rest of this article will walk you through the history of NASCAR’s most popular fuel.

What is Sunoco Green E15?

Since 2004, Sunoco has served as the exclusive fuel provider for Monster Energy NASCAR Cup Series, NASCAR XFINITY Series, and the NASCAR Camping World Truck Series. Over its long course of servicing NASCAR vehicles, Sunoco has powered more than 15 million miles of racing.

Sunoco Green E15 is a specially formulated fuel for high powered engines. Boasting an octane rating of 98, Green E15 has powered over 1300 victories in NASCAR alone. E15 is also the fuel used by the National Hot Rod Association, serving as the exclusive provider of racing fuel for all of their professional races.

With higher-rated fuels able to withstand greater compressive force, NASCAR engines are well-designed to handle fuels with high octane ratings. In fact, they need high-octane fuels to work properly at all. Sunoco introduced their Green E15 racing fuel in 2011. Beforehand, racers used Sunoco Supreme and Sunoco 2060 GTX, which contained no ethanol.

How Much Fuel Do NASCAR Racers Use?

NASCAR racers use a lot more fuel to travel the same distance as your average daily commute vehicle. In fact, NASCAR series vehicles get only five miles per gallon. Depending on how long the race track is, a typical NASCAR driver will guzzle anywhere from 40 to 125 gallons of fuel. Multiply that by the number of racers on the track, and a 43-car competition may use over 5000 gallons in a single race.

NASCAR vehicles are only designed with 18-gallon fuel tanks to save on space and weight. As such, a car must be refilled 2-4 times per race, creating a fuel window that plays such a significant role in the pit strategies. Pit crews must be lightning fast to refuel and ready up the car to get out on the track again.

Ethanol in Sunoco Green E15

Ethanol has been a big part of racing (and the fuel industry) for some time now. Sunoco introduced ethanol-infused gas in 2011 and thank goodness for that. E15 is significantly better for the environment since ethanol is derived from renewable plant sources like corn and wheat. The sugars from these and other natural resources can be fermented to make a viable fuel source.

Since the introduction of the new fuel, NASCAR has reduced their carbon emissions in all their races by 20%. This 98 octane-rated gas compares well with the power and performance of the previously used 110 octane-rated gas. In fact, it might even be more efficient.

How Do NASCAR Engines Use E15 Fuel?

For safety purposes, NASCAR has specifications and regulations that must be met for a stock car engine to be viable in NASCAR. It’s meant to level the playing field to some degree, but of course, manufacturers are always looking to find a way to get an edge on their competitors. The following denotes specifications for NASCAR engines.

  • Engine displacement of 5.86 L (358 cu in) pushrod (OHV) V8
  • Transmission must be 4-speed with a manual H-pattern
  • Weight must be at a minimum of 3,200 lb (1,451 kg) without driver and fuel and a minimum of 3,400 lb (1,542 kg) with a driver and fuel
  • A power output of 750 hp (559 kW) on tracks that are 1 mile or less, or  550 hp (410 kW) on tracks longer (2019)
  • Torque must be 720 N-m (530 ft-lb)
  • The fuel source must be Sunoco 93 MON, 104 RON, 98 AKI 85% unleaded gasoline + Sunoco Green Ethanol E15 15%
  • A standard fuel capacity of 17.75 US gallons or 67 liters on most race tracks
  • Fuel delivery must be via electronic multi-point indirect port fuel injection
  • Fuel must be injected by McLaren Electronic Systems
  • ECU provided by McLaren Freescale TAG-400N
  • A standard compression ratio of 12:1
  • Natural aspiration

Violations of any of these specifications or regulations—even something so simple as using the wrong fuel—can result in suspension from the competition. When the race is won, NASCAR teams will take away the vehicle and strip it down to its components to ensure that everything meets the guideline specifications.

Everything about modern racecars, from the engine specifications to the fuel injection system is regulated to avoid danger, and for good reason—there have been numerous racing-related deaths due to complete disregard for safety by the manufacturers.

NASCAR is still an incredibly dangerous sport, of course, but modern regulations have reduced some of the risk that previous NASCAR racers used to be exposed to every time they set foot inside those vehicles.

These engines are designed to run at very high revolutions per minute, with an undermounted camshaft. To prevent wear and tear, surfaces are coated with highly durable substances like carbo and titanium nitride, allowing parts under heavy friction stress to survive over the course of a race.

Final Thoughts

Gas has been an essential part of NASCAR since its inception, and the branding of gasoline has remained constant for almost two decades. Sunoco Green E15 is the current gas used by NASCAR and provides a sufficiently high-octane fuel rating to power the incredible engines in NASCAR vehicles.

Since 2011, Sunoco has been providing racers with ethanol-infused gas (hence the E15) that has significantly reduced the amount of carbon emissions produced by NASCAR at every race—20% to be precise. This gasoline is just as viable as the Sunoco brands of gas that were used up until 2011 from the start of their official partnership with NASCAR.

Written by Stefan Kristensen
I have been passionate about motorsports ever since I was a little boy. Back then, I cheered on the racing cars simply based on their colors. Later I fell in love with the many technical features, strategic plays, humans and their stories that all together drives this amazing sport to make it as interesting as it is.
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