Millers CVL Extra Petrol Octane Booster

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Millers CVL Extra – a powerful petrol octane booster

CVL Extra is a concentrated octane booster for high-performance, modified, classic and competition petrol engines. It raises the octane rating of unleaded fuel to prevent knock, detonation and pinking, letting tuned and high-compression engines run cleanly and deliver their best power. It is a strong dose – one 500ml bottle treats up to 20 litres of fuel – so it is ideal where you need a serious lift in octane, on the road, the track or the stage.

Running a classic that also needs lead replacement and ethanol protection? Our all-in-one VSPe Power Plus adds a smaller octane boost alongside valve seat protection – see our classic fuel guide to choose.

Product Information

One bottle (500ml) to 20 litres (maximum) unleaded petrol for all motorsport applications.

CVL Extra is a valve seat lubricant and combustion enhancer that protects against valve seat recession. Provides flame control, allowing engines to run more advance ignition timing, without the danger of pre-ignition or detonation. Specially formulated for high stress motorsport and track day events.

Features and Benefits

• Adds up to 4 octane numbers to base fuel.
• Enables older competition engines to run on unleaded fuel*.
• Proven chemistry protects against valve seat recession.
• Provides similar flame front control as lead, thereby enabling engines to run more advanced ignition timing without danger of pre-ignition or detonation.
• Mixes with leaded, unleaded, lead replacement petrol, and other fuels containing octane enhancing additives including oxygenates such as ethanol and MTBE.
• Equally effective in modern engines fitted with knock sensors and catalytic convertors.
• Protects against the corrosive effects of ethanol found in modern E5 and E10 unleaded petrol

CVL Extra – common questions

What does an octane booster do? It raises the octane rating of your fuel, which resists knock and detonation – letting high-compression, tuned and turbocharged engines run more ignition advance and make more power safely.

How much will it raise octane? At the full dose CVL Extra gives a significant octane lift – enough to run pump unleaded in engines that would otherwise need racing fuel. Use less for a smaller increase.

Is it just for racing, or road cars too? Both – it suits modified and high-compression road engines, classics and dedicated competition cars.

How much do I use? One 500ml bottle treats up to 20 litres of fuel for the maximum octane increase – adjust down for a milder boost.

Storage

📅 The date on the bottle is the date of manufacture, not a use-by date. Store at room temperature, away from strong direct light and heat, with the cap tightly closed. Any questions about an older bottle? Ask us.

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