Sunoco E98 Race Fuel

Sunoco E98 Ethanol Race Fuel

98% Ethanol Unleaded Racing Fuel for Dedicated Ethanol-Tuned Engines and Fuel Blending

Sunoco E98 is an unleaded, highly oxygenated race fuel containing 98% ethanol with approximately 2% gasoline denaturant. It is designed for racing applications that can take advantage of ethanol's detonation resistance, charge-cooling characteristics, and high oxygen content.

E98 requires substantially different fuel delivery and engine calibration than conventional gasoline-based racing fuel. Its stoichiometric air/fuel ratio is 9.1:1 and its oxygen content is 33.8% by weight, so fuel systems, injectors, carburetors, pumps, lines, and engine calibration must be compatible with high-ethanol fuel.

Sunoco E98 can be used directly in properly prepared racing applications or blended with compatible gasoline to create a desired ethanol concentration.

Key Features

• 98% ethanol by volume
• Approximately 2% gasoline denaturant
• Unleaded race fuel
• 33.8% oxygen by weight
• Stoichiometric air/fuel ratio of 9.1:1
• Does not contain metallic additives
• Compatible with oxygen sensors and catalytic converters
• Corrosion inhibitor added during manufacturing
• Can be used as an E98 race fuel or gasoline blending component
• Designed to meet ASTM D4806 for denatured fuel ethanol used for blending with gasoline
• Shelf life exceeds one year when properly stored
• Undyed

Why E98 Requires Dedicated Engine Tuning

E98 is not a drop-in replacement for gasoline racing fuel.

Its high ethanol and oxygen content requires substantially more fuel flow than a conventional gasoline-based fuel. The engine management system or carburetor must be calibrated for the different air/fuel requirements.

Sunoco E98 has a stoichiometric air/fuel ratio of approximately 9.1:1.

When converting an engine to E98, confirm that the following components can support the required fuel volume and are compatible with high concentrations of ethanol:

• Fuel injectors
• Fuel pumps
• Carburetors
• Fuel lines
• Fuel rails
• Regulators
• Seals and O-rings
• Fuel cells and storage containers

Consult the engine builder, tuner, fuel-injection supplier, or carburetor manufacturer when establishing the proper fuel-system capacity and calibration.

High Oxygen Content

Sunoco E98 contains approximately 33.8% oxygen by weight.

Its high oxygen content is one reason E98 can support high-performance engine combinations, but it also means fuel delivery must be calibrated accordingly. Running an ethanol fuel on a gasoline calibration can result in an excessively lean mixture.

Ethanol is also valued in racing applications for its resistance to detonation and evaporative cooling characteristics, which can help reduce intake-charge temperature.

E98 for Racing Applications

Sunoco E98 can be used in properly configured racing engines including applications involving:

• Drag racing
• Turbocharged engines
• Supercharged engines
• High-compression engines
• High-output naturally aspirated engines
• Other competition engines specifically tuned for high-ethanol fuel

The engine and fuel system must be designed or converted for high-ethanol operation before using E98.

E98 as a Blending Fuel

Sunoco E98 can also be blended with compatible gasoline to create a targeted ethanol concentration.

This allows racers and tuners to prepare ethanol blends suited to their engine, fuel system, calibration, or competition requirements.

Actual final ethanol concentration depends on:

• Ethanol concentration of the E98
• Ethanol content already present in the gasoline
• Volume of each fuel used in the blend

Measure the final ethanol concentration when precise blending is required rather than assuming that the finished mixture will match a calculated nominal value.

ASTM D4806 Denatured Fuel Ethanol

Sunoco E98 is designed to meet ASTM D4806, the standard specification for denatured fuel ethanol intended for blending with gasoline.

The fuel includes an approved gasoline denaturant and a corrosion inhibitor added during manufacturing.

Fuel-System Compatibility

High concentrations of ethanol can interact differently with fuel-system materials than conventional gasoline.

Before using Sunoco E98, verify compatibility with the manufacturers of your:

• Fuel pump
• Injectors
• Carburetor
• Fuel lines
• Seals
• Fuel cell
• Storage container

Components designed only for gasoline should not automatically be assumed compatible with E98.

Oxygen Sensors and Catalytic Converters

Sunoco E98 does not contain metallic additives and is identified as compatible with oxygen sensors and catalytic converters.

Storage and Shelf Life

Ethanol-based racing fuels can absorb moisture from the surrounding air, so proper storage is especially important.

Store Sunoco E98:

• In a dark or opaque container
• In a tightly sealed container
• Away from prolonged exposure to air
• Where temperature remains relatively stable
• In a fuel-compatible container designed for high-ethanol blends

Under appropriate storage conditions, Sunoco lists a shelf life of more than one year.

Technical Details

Sunoco does not publish a conventional (R+M)/2 octane value for E98. Typical technical values should be used for reference and tuning guidance rather than treated as guaranteed batch specifications.

Frequently Asked Questions

What is Sunoco E98 Race Fuel?
Sunoco E98 is an unleaded racing fuel containing 98% ethanol with approximately 2% gasoline denaturant. It is intended for engines and fuel systems specifically configured and tuned for high-ethanol fuel.

What does E98 mean?
E98 refers to the fuel's ethanol concentration. Sunoco E98 contains approximately 98% ethanol by volume.

Is E98 98 octane?
No. The “98” in E98 refers to approximately 98% ethanol, not a 98-octane rating. Sunoco does not publish a conventional (R+M)/2 octane number for E98 on its current product specification.

What is the stoichiometric air/fuel ratio of Sunoco E98?
Sunoco lists a stoichiometric air/fuel ratio of approximately 9.1:1.

Does E98 require different tuning than gasoline?
Yes. E98 requires significantly more fuel flow than conventional gasoline and must be used with an appropriate ethanol calibration. Injector size, fuel-pump capacity, carburetor configuration, fuel pressure, and engine management may all require changes.

How much oxygen is in Sunoco E98?
Sunoco E98 contains approximately 33.8% oxygen by weight.

Can Sunoco E98 be used in a gasoline engine?
Only if the engine and fuel system are compatible with high-ethanol fuel and properly calibrated for E98. It should not be treated as a direct replacement for gasoline without appropriate fuel-system and tuning changes.

Can Sunoco E98 be mixed with gasoline?
Yes. Sunoco identifies E98 for use both as a race fuel and as a blending component for creating a desired ethanol concentration.

What is the difference between E98 and E85?
The primary difference is ethanol concentration. E98 contains approximately 98% ethanol, while E85 fuels contain a lower concentration of ethanol. The higher ethanol concentration of E98 changes fuel demand, stoichiometric air/fuel ratio, energy content, and tuning requirements.

Does Sunoco E98 contain lead?
No. Sunoco E98 is an unleaded fuel.

Does Sunoco E98 contain metallic additives?
No. Sunoco E98 does not contain metallic additives.

Is Sunoco E98 safe for oxygen sensors?
Yes. Sunoco identifies E98 as compatible with oxygen sensors when the engine and fuel system are otherwise configured correctly for the fuel.

Is Sunoco E98 safe for catalytic converters?
Sunoco states that E98 will not harm catalytic converters. The overall engine calibration must still be appropriate for the fuel and emissions system.

Does Sunoco E98 meet ASTM D4806?
Sunoco E98 is designed to meet ASTM D4806, the standard specification for denatured fuel ethanol for blending with gasoline.

How long does Sunoco E98 last in storage?
When stored in a dark, tightly sealed, compatible container at a stable temperature, Sunoco lists a shelf life of more than one year.

Does E98 absorb water?
Ethanol-based fuels can absorb moisture from the surrounding air. Keep E98 tightly sealed and minimize prolonged exposure to open air during storage and handling.

What fuel-system parts need to be compatible with E98?
Fuel pumps, injectors, carburetors, fuel lines, rails, regulators, seals, O-rings, fuel cells, and storage containers should all be verified for compatibility with high concentrations of ethanol.