If you are building or updating a race car, the fuel cell is one of the parts you do not want to guess on.
The right choice depends on the car, the championship, the age of the tank, the installation and the exact wording of the regulations you are building to. FT3, FT3.5 and FT5 are not just random product labels. They refer to FIA fuel bladder standards used across different levels of motorsport.
This guide gives you the simple version: what the terms mean, what you need to check, and when to speak to someone before ordering.
What do FT3, FT3.5 and FT5 mean?
FT3-1999, FT3.5-1999 and FT5-1999 are FIA specifications for safety fuel bladders. The FIA's own guidance says these three specifications sit under the FIA Standard for Safety Fuel Bladders, and that users should check Appendix J Article 253 and the technical regulations of the relevant championship before choosing a tank.
In plain English, they are different approval levels for motorsport fuel bladders. A higher or different standard is not automatically "better" for every car. What matters is what your championship requires and what will physically work in the vehicle.
Why the championship matters
Two cars can look similar and need different fuel tank solutions because they run in different series.
Before buying, check:
- Championship regulations
- Class regulations
- FIA or MSUK requirements
- Tank age and validity rules
- Whether the car needs a standard-size cell or a custom system
- Filler position, venting and installation requirements
- Whether your scrutineer expects a specific label or homologation reference
The FIA also publishes technical lists of homologated fuel bladders under FT3-1999, FT3.5-1999 and FT5-1999, which is useful when checking whether a specific bladder type is recognised.
FT3, FT3.5 or FT5 - which should you choose?
As a broad guide:
FT3 is commonly seen in club, national and historic motorsport where the regulations call for an FIA-approved fuel bladder but do not demand a higher specification.
FT3.5 may be used where a higher performance or specific technical requirement is written into the regulations.
FT5 is typically associated with more demanding applications where the regulations or build specification require the highest of the three fuel bladder standards.
Do not choose by guessing. The correct answer is always the one written into your championship rules.
What to check before ordering
Before buying a fuel cell, you should know:
- The championship and class.
- The required standard: FT3, FT3.5 or FT5.
- The tank volume you need.
- The available space in the car.
- The filler position.
- The outlet and venting requirements.
- Whether you need a complete system or bladder only.
- Whether the tank needs to fit an existing container or wheel well.
- Any expiry or validity rules.
- Whether the car will need scrutineering paperwork.
This is where a quick conversation saves money. A fuel cell is not the same as a tyre pressure gauge or a bracket. If you buy the wrong version, you may not find out until the car is being inspected.
Where VMEP fits
VMEP supplies motorsport fuel cells, fuel system parts and transport/storage equipment for race teams, workshops and private competitors. If you already know the product you need, you can order directly. If you are unsure, send the championship, car model and any existing tank details before buying.
For custom or higher-value fuel system work, include photos, dimensions and regulation references where possible. That gives us enough information to point you in the right direction.
Final advice
Do not buy a fuel cell only because it "looks right".
Buy it because it matches:
- Your championship rules
- Your car
- Your installation
- Your scrutineering requirements
- Your budget
If in doubt, check the regulations first, then speak to VMEP before ordering.
View Fuel Safe fuel cells or contact VMEP for help choosing the right system.