If you've ever chosen between "regular" and "premium" petrol, you've seen numbers like 91 or 95 on the pump. Those numbers are the octane rating. A higher number usually means the fuel can handle more pressure in the engine before it starts to "knock" or "ping".

Behind those numbers is a big challenge for refineries:

How do we keep making higher-octane, cleaner fuel without huge investments or harmful additives?

For many years, some octane boosters contained metals like lead or manganese. Today, refineries around the world are moving toward non-metallic (metal-free) octane boosters that are safer for engines, people and the environment.

One of the early Indian solutions in this space is CRISTOL OB-77, a non-metallic octane booster developed by Krishna Antioxidants Pvt. Ltd. under the Make in India initiative, in collaboration with a leading Indian refinery.

Quick Refresher: What is octane, and why boost it?

The octane number is a rating that shows how much gasoline can be compressed in the engine before it starts to knock.

In other words, the octane number indicates a fuel’s ability to withstand compression while maintaining smooth combustion in the engine cylinder. If the octane rating is too low for a specific engine:

• The fuel–air mixture burns unevenly
• The engine experiences knocking, which feels like a harsh pinging noise
• Over time, this can cause vibration, wear and damage inside the engine

Every engine has a minimum octane requirement based on its design and compression ratio. 

When the fuel at the refinery doesn't reach that level by itself, refineries have three options:

1. Upgrade refinery hardware (expensive and slow)
2. Blend in more high-octane components (often costly or limited in supply)
3. Add an octane booster – a small-dose additive that raises octane

Option 3 is often the fastest and most flexible, which is where products like CRISTOL OB-77 come in.

Why are metallic octane boosters being phased out?

In the past, many countries used leaded petrol to raise octane. The lead worked technically very well, but it was extremely harmful. Global health agencies now credit the phase-out of leaded petrol with preventing over a million premature deaths per year and reducing heart disease, cancer and brain damage in children.

After lead, some fuels used metallic additives like MMT, which contains manganese. Studies and regulators have raised concerns that:

• Manganese particles in exhaust can be a neurotoxin when inhaled.
• Metallic additives can leave deposits on spark plugs, valves, oxygen sensors and catalytic converters, affecting performance and emissions.

Because of these issues, many car makers and regulators now strongly prefer, or even require, metal-free ways to increase octane.

What makes non-metallic octane boosters different?

Non-metallic octane boosters are made from organic, metal-free chemistry. In everyday terms, that means:

• No lead, no manganese, no other poisonous metals
• Designed to help fuel resist knock without leaving metallic residues
• Gentler on modern engines and on emissions equipment like catalytic converters

Instead of relying on metals, these additives adjust how the fuel burns, resulting in smoother, more controlled combustion, especially in high-compression engines.

Introducing CRISTOL OB-77 – India's non-metallic octane booster

CRISTOL OB-77 is CRISTOL’s flagship non-metallic octane booster for gasoline, engineered to enhance fuel octane performance while ensuring smooth combustion and engine compatibility, with the following key attributes:

• A user- and environment-friendly additive
• Non-metallic and of organic origin
• Suitable for all unleaded fuels, including high-performance and competition engines
• Designed to substantially increase RON (Research Octane Number) and reduce knocking

It is supplied in liquid form and can be added directly into existing MS (motor spirit) blending systems at the refinery, so no major new equipment is needed.

CRISTOL is among the first manufacturers in India to bring such a non-metallic octane booster from concept to full commercial scale, and to build an export portfolio that now includes several regions worldwide. The brand has also been introduced into NAFTA markets as part of CRISTOL's global expansion, supported by its U.S. EPA registration as a fuel additive.

What Kind of Octane Boost can CRISTOL OB-77 Deliver?

CRISTOL OB 77 was evaluated through laboratory testing and real-world refinery use. Here’s what the results showed:

Laboratory tests (SWRI, USA)

At Southwest Research Institute (SWRI) in the U.S., tests followed the standard ASTM D2699 procedure for Research Octane Number. When 1.5% OB-77 was added to different base fuels:

• A fuel at 75.6 RON went up to 83.0 RON
• A fuel at 85.2 RON went up to 91.0 RON
• A fuel at 89.3 RON went up to 94.2 RON

Based on these and additional data, response curves show that for fuels with an initial RON of approximately 85–87, a 1.5% dosage of OB-77 can increase the octane rating by about 5–6 points.

Why refineries are making the switch

Putting it all together, refineries are moving to non-metallic boosters like CRISTOL OB-77 because they offer a balance of:

1. Cleaner chemistry
   • No poisonous metals like lead or manganese
   • Better aligned with modern health and environmental expectations
      
2. Engine and catalyst protection
   • Less risk of metal deposits on spark plugs, valves and catalytic converters
   • Supports long-term durability of engines and emission systems
      
3. Flexible, low-capex octane control
   • Can be incorporated into existing blending systems
   • Let's refineries pull more low-octane naphtha into the gasoline pool while still meeting octane targets
      
4. Global compatibility and branding
   • OB-77 is registered with the U.S. EPA as a fuel additive, helping refiners align with strict international regulations
   • CRISTOL's exports to multiple regions, including NAFTA, show that the product is accepted in diverse markets

Ultimately, non-metallic octane boosters help refineries deliver cleaner, higher-octane gasoline without visible changes for the driver but with big benefits for engines and air quality.

What this means for everyday drivers

You probably won't see "CRISTOL OB-77" mentioned at your local petrol pump. But if your fuel supplier uses it, you may enjoy:

• Smoother driving with less knocking or pinging
• Fuel that supports better combustion efficiency and helps conserve energy
• Reduced risk of long-term engine knock damage
• Cleaner exhaust, as better combustion means fewer unburned hydrocarbons

In short, non-metallic octane boosters are one of the "behind-the-scenes" tools that help make modern petrol cleaner, safer and more reliable.

FAQs

1. What exactly is a non-metallic octane booster?

It's a liquid additive, used in very small amounts at the refinery, that raises gasoline's octane number without using metals like lead or manganese. CRISTOL OB-77 uses organic (carbon-based), metal-free chemistry to improve knock resistance.

2. Why are metallic octane boosters considered a problem now?

Metal additives can release harmful particles into the air and leave deposits in engines and emission systems. Leaded petrol has been completely phased out worldwide due to its serious health impacts, and manganese-based additives like MMT have been linked to neurotoxicity and catalyst fouling.

3. What kind of Octane Boost can CRISTOL OB-77 deliver?

Lab and refinery tests show that, at typical treaty rates of 1.0–2.0% by volume, OB-77 can raise RON by 5–6 points in many fuels, for example, from about 85 to 90–91 RON, or from roughly 92 to 95 RON.

4. Does OB-77 change other fuel properties?

According to refinery trials, adding OB-77 at typical dosages does not significantly alter key physical properties, such as vapour pressure, distillation recoveries, or benzene content. Finished fuels still met relevant Euro IV specifications.

5. Is OB-77 safe for modern cars with catalytic converters?

Yes. OB-77 is non-metallic and "doesn't contain poisonous metals like Lead, Manganese, making it much kinder to catalytic converters and oxygen sensors than metallic additives.

6. Where is CRISTOL OB-77 used today?

OB-77 is manufactured in India and exported to several countries across Asia, Europe, the Middle East, Latin America and other regions. With its U.S. EPA registration, it can also be used in North American (NAFTA) markets as part of CRISTOL's growing international portfolio.