Mid-Grade (89 Octane) Gasoline is a blended motor fuel designed to provide a balanced compromise between cost, performance, and engine protection. Positioned between regular (87 octane) and premium (91–94 octane) gasoline, it is engineered for vehicles that benefit from moderate knock resistance without the higher cost of premium fuels.
The 89 octane rating reflects the fuel’s anti-knock index (AKI), measuring its ability to resist pre-ignition and engine knocking. By minimizing abnormal combustion, mid-grade gasoline supports smoother acceleration, improved drivability, and long-term engine reliability.
Technical Specifications
Octane Rating (AKI): 89
Hydrocarbon Range: C4–C12
Density: ~0.72–0.76 kg/L (temperature dependent)
Energy Content: ~114,000–116,000 BTU/gal
Flash Point: ~ –40°C
Auto-Ignition Temperature: ~280–300°C
Key Characteristics
Enhanced Knock Resistance
Protects engines operating at moderate compression ratios and variable load conditions
Balanced Power Output
Allows engines to operate closer to optimal ignition timing without premium fuel cost
Cleaner Burning Properties
Detergent additives reduce injector fouling and carbon buildup, improving efficiency
Broad Engine Compatibility
Suitable for vehicles recommended for 88–90 octane fuel, passenger cars, SUVs, fleet vehicles, and approved older premium engines
Refining & Blending Properties
Produced through controlled blending rather than direct distillation:
Atmospheric & Vacuum Distillation – Base fuel separation
Catalytic Reforming – High-octane reformate production
Isomerization – Improves octane and cold-start behavior
Alkylation – Clean-burning high-octane components
Final octane is achieved by blending straight-run gasoline with reformate, alkylate, and regulated oxygenates (E5–E10 where permitted).
Additive Package
Detergents – Clean injectors and valves
Antioxidants – Prevent fuel oxidation
Corrosion inhibitors – Protect fuel systems
Anti-icing agents – Control moisture issues
Metal deactivators – Prevent catalytic degradation
Performance & Engine Benefits
Improved throttle response vs regular gasoline
Reduced engine knocking and vibration
Stable combustion across varied loads
Enhanced engine longevity and reliability
Emissions & Environmental Impact
Lower CO and HC emissions than lower-grade fuels
Compatible with catalytic converters and oxygen sensors
Supports BS-VI, Euro 6, and EPA Tier 3 standards
Ethanol blends help reduce fossil carbon footprint
Storage & Handling
Stored in approved steel fuel tanks
Highly flammable – grounding and bonding required
Shelf life: 3–6 months (extended with stabilizers)
Sensitive to water and particulate contamination
Standards & Specifications
ASTM D4814 (USA)
EN 228 (Europe – equivalent mid-octane blends)
IS 2796 (India – motor gasoline standards)
Typical Applications
Passenger vehicles requiring mid-octane fuel
Fleet vehicles balancing cost and protection
Urban and highway driving
Engines operating under moderate stress or load