How to Mix 2 Stroke Fuel for Petrol RC Cars

Mixing 2-stroke fuel for your large-scale petrol RC car might seem a bit daunting at first, but it's a straightforward process once you know the basics. Just like a full-sized dirt bike or performance engine, using the right products and ratios is essential to keep your RC car running reliably and delivering maximum power. Whether you're breaking in a new Rovan 32cc Baja V2 or prepping for a weekend bash session, getting your fuel mix right is step one.

Why Getting Your 2-Stroke Fuel Mix Right Matters

Running the exact fuel-to-oil ratio for your petrol RC car is crucial. There are plenty of opinions out there about leaning out your fuel for more power, but we've found that skimping on oil doesn't give you a noticeable performance boost—it just wears your engine components out faster. For the best balance of performance and engine longevity, stick to a standard 25:1 ratio.

What You Need to Mix 2-Stroke Fuel

Before you start pouring, make sure you have the right supplies. Using quality ingredients makes a massive difference to how your engine runs.

The Right Petrol

Choose a good quality unleaded petrol with an octane rating between 91 and 98 RON. Avoid ethanol-blended fuels (like E10) if possible, as ethanol can attract moisture and degrade the plastic and rubber components in your Fuel Tanks & Tubing over time.

Premium 2-Stroke Oil

Don't settle for the cheap stuff you'd put in a lawnmower. Your RC car engine revs much higher and runs hotter, so it needs proper lubrication. We recommend a high-quality, fully synthetic oil designed for high-performance 2-stroke engines, such as Castrol Power 1 TTS Racing 2T.

A Clean Mixing Container

You'll need an approved fuel container. Petrol is a volatile solvent, so you can't just use an old milk jug. A dedicated Rovan 1L Mixing Bottle takes the guesswork out of the process, as it has the ratios clearly marked on the side. For storing larger batches, a proper Rovan Green 5L Jerry Can is the way to go.

The Standard RC Fuel Mix Ratio: 25:1 Explained

The most common ratio for large-scale RC petrol engines is 25:1. This simply means 26 parts in total—25 parts petrol to 1 part oil. To achieve this, you need to add 40ml of oil for every 1 litre of petrol.

Here is a quick reference table for mixing 25:1 fuel:

Step-by-Step: How to Mix 2-Stroke Fuel

Follow these steps to safely and accurately mix your RC fuel.

Step 1: Prepare your workspace

Always mix fuel in a well-ventilated area—outside is best. Wear safety glasses to protect your eyes and avoid skin contact. Ensure your mixing bottle or jerry can is completely free from dust, dirt, and contaminants. Dirty fuel is a quick way to damage your engine.

Step 2: Measure the petrol

If you are using a ratio mixing bottle, fill the main chamber with unleaded petrol up to the desired fill line (for example, the '1' mark for one litre). If you are using a standard jerry can, use a measuring jug to pour in exactly 1 litre of petrol.

Step 3: Measure and add the oil

Using the separate oil chamber on your mixing bottle, fill the oil up to the matching '1' mark on the 25:1 scale. If you're doing it manually, measure out exactly 40ml of your Castrol fully synthetic oil and pour it into the petrol.

Step 4: Combine and mix thoroughly

Seal your container tightly. If using a mixing bottle, tip the chambers together to combine the fluids. Give the bottle or jerry can a good shake for about 30 seconds to ensure the oil and petrol are completely blended.

Step 5: Store safely

Never store fuel in a mixing bottle long-term. Transfer the mixed fuel into an approved, sealed jerry can. Mixed 2-stroke fuel has a shelf life of roughly 3 to 6 months depending on the climate.

Common Mixing Mistakes to Avoid

• Guessing the ratio: Eyeballing your oil is a recipe for a seized engine or fouled spark plugs. Always measure accurately. A sharpie mark on your mixing bottle's 25:1 line can make it easier to see in poor lighting.

• Leaving fuel in the car: Always drain your RC buggy's fuel tank after a bash session. Leaving mixed fuel sitting in the tank causes it to go stale and can gum up your carburettor.

• Using old fuel: If your mixed fuel has been sitting in a jerry can for more than six months, safely dispose of it and mix a fresh batch.

Ready to Bash?

Once your fuel is mixed, you're ready to hit the track. If you're looking to upgrade your setup or need replacement parts for your petrol beast, check out our full range of Rovan vehicles and accessories. Got a specific part in mind? Enter your car model into our Part Finder tool to find every compatible upgrade and replacement part.