How to find the right Automotive Performance Fuel System Fittings AI guide
Written by an AI model from its trained knowledge.
What the AI looks for in Automotive Performance Fuel System Fittings
- AN size and thread
- AN fittings use a 37 degree flare; common sizes are -6 (9/16-18), -8 (3/4-16) and -10 (7/8-14), and both halves must match AN size describes both line diameter and thread, so mismatched sizes simply will not seal.
- Flare angle
- Never mate 37 degree AN fittings with 45 degree SAE or inverted-flare automotive fittings The fittings may thread together but the seats do not match and will leak under pressure.
- Hose type match
- PTFE-lined hose needs PTFE-specific hose ends with an olive or ferrule; rubber braided hose uses standard hose ends; push-lock barbs are only for push-lock hose at moderate pressure Using rubber-hose ends on PTFE line is a leading cause of fuel leaks at the hose end.
- Port thread type
- Use ORB (O-ring boss) adapters for ORB ports and NPT only where the port is NPT, sealed with fuel-safe thread sealant NPT is tapered and seals on the thread; ORB seals on the O-ring, and swapping them leaks or cracks housings.
- Fuel compatibility of seals and finish
- For E85 and methanol, confirm O-rings and hose are rated for alcohol fuels Standard seals swell or degrade in alcohol fuels.
Brands that matter
- Earl's: Long-standing AN fittings and hose ends including PTFE-specific lines.
- Russell: Wide range of AN adapters, hose ends and plumbing kits.
- Aeromotive: Fuel-specific fittings and ORB adapters to match its pumps and regulators.
- Vibrant Performance: Large catalog of adapters, weld bungs and specialty fittings.
- Fragola: AN hose ends and fittings with PTFE-compatible options.
- XRP: Motorsport-grade hose ends and adapters.
- Holley: EFI-focused fittings and hose ends sold alongside its fuel systems.
What to avoid
- PTFE thread tape on fuel fittings, which can shed pieces into regulators and injectors.
- Mixing hose ends from one brand with hose from another unless both specify compatibility.
- Using push-lock barbed fittings on high-pressure EFI lines without checking the pressure rating.
- Unbranded anodized fitting assortments with no thread or pressure specification.
Questions
Can I put an AN fitting on stock hard line?
Only with an adapter made for that line's flare type or a proper tube nut and sleeve on a 37 degree flared tube; stock lines often use a different flare or quick-connect end.
Is ORB the same as AN?
ORB ports share AN thread sizes but seal with an O-ring on a flat face instead of a flare, so you need an ORB-to-AN adapter, not a straight AN fitting.