What Fuel Is Used In IndyCar? | Ethanol Blend, Explained

You’ll hear “E85” tossed around any time IndyCar fuel comes up. That’s a solid shorthand, but the real answer has a few layers: what’s in the blend, how the series controls it, and what changed in 2023.

What Fuel IndyCar Uses Today And Why It Changed

In the current NTT INDYCAR SERIES era, the fuel story centers on ethanol. For years, the series ran an ethanol-gasoline blend that fans often call E85. Starting with the 2023 season, IndyCar and Shell introduced a race fuel classified as 100% renewable, built with a large share of second-generation ethanol and another renewable component in the hydrocarbon portion of the blend.

The series wanted a fuel that could match the demands of a 2.2-liter, twin-turbocharged V6 while meeting tighter sourcing and lifecycle targets.

The goal stayed the same: use an ethanol-led formulation that behaves predictably, then lock it down with strict supply and sampling rules.

Two Answers You’ll See Online

When people ask what fuel is used, they’re usually looking for one of these:

• The traditional shorthand: E85-style race fuel (ethanol with a smaller gasoline-like fraction).
• The current headline: Shell 100% Renewable Race Fuel used across the series since 2023.

Both point at the same foundation: ethanol as the primary energy carrier, chosen because it can handle high cylinder pressures and resists knock when the turbochargers are pushing hard.

Why Ethanol Fits A Turbo IndyCar Engine

IndyCar engines live in a narrow window where heat, pressure, and timing all matter. Ethanol helps in three practical ways that race engineers care about:

• Octane and knock resistance: High-ethanol fuels tolerate aggressive boost and spark timing without detonation.
• Charge cooling: Ethanol absorbs heat as it vaporizes, which can lower intake charge temperatures and calm combustion.
• Consistency: A tightly specified fuel blend reduces run-to-run surprises, so setup changes come from the car, not the pump.

There’s a trade-off. Ethanol carries less energy per gallon than pure gasoline, so cars burn more volume to make the same power. In racing, that becomes a strategy lever: fuel window, stint length, caution timing, and pit sequencing all hinge on it.

What Fuel Is Used In IndyCar? Trackside View Of The Blend

If you’re standing in the paddock, “what fuel is used” looks less like a chemistry class and more like a logistics system. The fuel arrives through the official supplier pipeline, is stored and dispensed under series control, and is sampled and tested so the blend stays within spec.

Teams don’t blend their own. They tune engines and calibrations around the known properties of the supplied fuel. That keeps the competition centered on engineering, setup, and execution.

What “100% Renewable Race Fuel” Means In Practice

IndyCar’s 2023 change was framed as a 100% renewable formulation. The public description from the series says the blend contains a large share of second-generation ethanol paired with another renewable component to make up the rest of the formulation, with a stated lifecycle emissions reduction target versus fossil-based gasoline.

From a fan’s angle, the headline is simple: the series still relies on ethanol as the backbone, but the non-ethanol fraction is no longer fossil-derived in the same way a traditional gasoline fraction would be.

Want the official wording? The announcement is on IndyCar’s own site: Shell Proud To Power INDYCAR with 100% Renewable Race Fuel.

How IndyCar Fuel Evolved From Methanol To Modern Ethanol

Fuel choices in IndyCar have always been tied to safety, performance, and the sport’s rulebook. Methanol became the standard for decades after the mid-1960s. It burns cooler than gasoline and can be extinguished with water, but its flame can be hard to see in daylight. Those traits shaped safety procedures for generations of teams and track crews.

The series later moved away from methanol and into ethanol-based fuels. The 2007 season marked a major pivot: the Indy Racing League moved to 100% fuel-grade ethanol. Honda’s announcement from that era lays out the decision and context from the manufacturer side: Indy Racing League Makes Move To 100% Fuel-Grade Ethanol.

Over time, the ethanol story gained another layer: blends that include a hydrocarbon fraction (often described as “gasoline” in plain talk) and, later, a renewable hydrocarbon component in the Shell formulation used from 2023 onward.

Fans often mix up these eras because the shorthand sticks. People hear E85 once and use it forever. It’s close enough for casual talk, but if you’re trying to be precise, it helps to separate the timeline.

Fuel Timeline At A Glance

The table below keeps the big fuel eras straight without turning it into a history lecture.

Era	Primary Fuel Type	What It Meant At The Track
Mid-1960s to 2005	Methanol	Cooler burn and water-extinguishable fires shaped safety gear and response.
2006	Methanol/Ethanol blend	Transition season used to validate ethanol use under race conditions.
2007	Fuel-grade ethanol (E100)	Full switch to ethanol; teams recalibrated for different energy content and flow.
Late 2000s to early 2010s	Ethanol blend with small hydrocarbon fraction	Blending helped cold starts and handling traits, while keeping ethanol-centered combustion.
DW12 era (2012 onward)	High-ethanol blend commonly called E85	Stable spec fuel suited the twin-turbo V6 and tightened parity across teams.
2023 to present	Shell 100% Renewable Race Fuel (ethanol-led)	Renewable hydrocarbon component joined ethanol base while preserving performance targets.
Race weekends	Single-supplier, spec distribution	Controlled storage, dispensing, and sampling reduce fuel as a “secret weapon.”

What The Fuel Must Do During A Race

IndyCar fuel is built for a turbo engine that spends lap after lap near its limits. Teams need a blend that stays steady under heat, boost, and long stints, so the car’s behavior stays predictable.

• Resist knock: Lets teams run the boost and timing targets the rules allow.
• Cool the intake charge: Ethanol’s evaporation can pull heat out of the incoming air.
• Stay consistent: Tight specs help teams trust their data from session to session.
• Work with pit equipment: Safe, repeatable fueling matters as much as peak power.

How Fuel Rules Keep Racing Fair

Spec fuel only works if the rules keep everyone honest. IndyCar does that with supplier control, sampling, and lab checks. You’ll see officials take fuel samples during events, then compare them to reference standards. If a sample drifts outside the allowed ranges, penalties can follow.

Teams still have room for creativity in mapping, turbo control, and drivability. They just don’t get to show up with a “special batch” that changes combustion speed or raises octane beyond spec.

How The Fuel Touches Strategy

Even with everyone on the same spec fuel, the blend shapes race calls. Here’s where it shows up:

• Stint length: High-ethanol fuel can mean higher volume burn, shifting the lap count per tank.
• Caution math: Yellow flags change the fuel number fast, and teams can stretch or short-fill.
• Push-to-pass usage: Extra power demand can shift consumption and temp targets.
• Traffic management: Running in dirty air changes cooling and can change how aggressively a team uses power.

This is the part casual viewers feel even if they don’t name it. When a driver is told to hit a fuel number, it’s not just saving gas. It’s managing how that ethanol-centered blend is flowing through an engine that’s on the edge all day.

IndyCar Fuel Versus Gasoline, E10, And E15

Street fuel blends like E10 and E15 exist to meet road-vehicle standards and supply needs. IndyCar fuel exists to win races. That difference shows up in blend targets and quality control. The series fuel is formulated and handled as a racing product, not a pump product.

Here’s a practical way to think about it: road fuels are designed to work across thousands of engines, climates, and storage conditions. IndyCar fuel is designed for one engine family, one rule set, and a controlled supply chain.

Fuel Type	Typical Ethanol Share	Where You’ll See It
E10 gasoline	Up to 10%	Common pump fuel in many regions for regular road cars.
E15 gasoline	Up to 15%	Some pump stations; not approved for every vehicle or every year.
E85 (street flex-fuel)	Up to 85%	Flex-fuel vehicles designed for high ethanol content.
IndyCar spec race fuel	Ethanol-led formulation	Single-supplier fuel under series control, built for twin-turbo race engines.

Common Misunderstandings Fans Have About IndyCar Fuel

Fuel talk online gets messy because people mix eras and labels. Here are the misconceptions that come up most often, with the clean way to think about each one.

“It’s Just Pump E85”

No. IndyCar fuel is a racing blend with tight specifications and controlled handling. Pump E85 can vary by region and season. That variability is fine for flex-fuel street cars built to tolerate it. Race teams want consistency.

“Ethanol Means Less Power”

Ethanol has less energy per gallon than gasoline, so consumption can rise. Power is a different story. With the right blend and engine tuning, ethanol’s knock resistance and cooling traits can let teams run the boost and timing they need.

“The 2023 Fuel Change Rewrote Engine Setup”

The 2023 switch was designed as a drop-in change at the series level. Teams still tune within the same engine and rules set. The fuel supply chain and formulation changed, but the goal was to keep performance consistent while meeting the series’ renewable classification target.

If You Want One Sentence To Repeat

IndyCar runs on an ethanol-based, spec racing fuel, and since 2023 that fuel is supplied as Shell’s 100% renewable formulation built around second-generation ethanol.