A sub fuel tank in a car is an additional fuel storage system that works alongside the main tank. It increases the total fuel capacity, extending driving range and offering more flexibility for long trips or off-road use.
Purpose of a Sub Fuel Tank
Sub tanks are designed to support drivers who need extra fuel without carrying external containers. They are common in off-road vehicles, touring SUVs, and some utility trucks.
- Extended Range – Allows more miles between refueling stops.
- Emergency Backup – Acts as a reserve if the main tank runs low.
- Convenience – Reduces the need for frequent fuel station visits.
How a Sub Fuel Tank Works
Depending on the vehicle, the sub tank can be connected directly to the fuel system or require manual transfer. Some are factory-installed, while others are aftermarket upgrades.
- Integrated Systems – Automatically feed fuel into the main tank when needed.
- Manual Transfer – Uses a switch or pump to move fuel between tanks.
- Independent Setup – Operates separately for specific uses like generators or auxiliary engines.
Benefits & Considerations
While sub tanks add flexibility, they also require proper installation and maintenance for safety and performance.
- Travel Confidence – Ideal for remote trips with limited fuel stations.
- Weight and Space – Extra fuel adds weight and may take up cargo room.
- Maintenance Needs – Regular checks help prevent leaks and system failures.
Adding a sub fuel tank in a car is a practical upgrade for those who travel long distances, venture off-road, or operate in remote areas. It ensures more range, flexibility, and peace of mind when fuel access is limited.