Product Description
2006-2011 Honda Civic Si FA5 / FG2 Complete PTFE Fuel System (Level 4)
The JBtuned Level 4 Complete Fuel System replaces the factory fuel-delivery plumbing on 2006-2011 USDM Honda Civic Si FA5 sedans and FG2 coupes with a complete aftermarket tank-to-engine-and-back feed-and-return system.
The original chassis fuel feed is replaced with JBtuned 350 Series PTFE fuel hose, and a dedicated 6AN return is added from the engine bay back to the fuel tank.
Choose a 6AN or 8AN main fuel feed based on the requirements of the build. The return remains 6AN with either configuration.
This is Level 4 in the JBtuned fuel-system architecture: “I want to replace everything.”
Level 4 at a Glance
- Fitment: 2006-2011 USDM Honda Civic Si FA5 sedan and FG2 coupe
- Engine: Compatible K-Series Civic Si applications
- System Type: Complete tank-to-engine-and-back aftermarket feed-and-return fuel system
- Factory Chassis Fuel Feed: Replaced
- Dedicated Fuel Return: Added
- Feed Line: 6AN or 8AN
- Return Line: 6AN
- Fuel Hose: JBtuned 350 Series PTFE
- Fuel Compatibility: Pump gasoline, E85 / ethanol and compatible race fuels
- Fuel Rail: Compatible aftermarket fuel rail required
- Fuel Pressure Regulator: Compatible external adjustable regulator required
- Fuel Filter: Optional - not included with the base system unless selected
- Flex-Fuel Sensor Provision: Optional plumbing configuration
- Ethanol-Content Sensor: Not included
- Fuel Pump: Not included unless selected separately
- Fuel Pump Hanger Upgrade: Available as an option
What Comes With the Base Level 4 System
- Complete JBtuned 350 Series PTFE fuel-feed plumbing from the fuel tank to the engine bay in the selected 6AN or 8AN size
- Complete JBtuned 350 Series PTFE 6AN return plumbing from the engine bay back to the fuel tank
- Pre-assembled fuel-line assemblies configured for the selected fuel-system options
- Fuel-rail connection components for the selected configuration
- Fuel-pressure-regulator connection components for the selected configuration
- Required AN connection hardware for the configured base fuel system
Exact line and connection configurations vary depending on feed-line size, fuel rail, regulator, feed location and selected options.
The base system does not include a fuel filter, ethanol-content sensor, fuel rail, fuel pressure regulator or fuel pump unless specifically selected or purchased separately.
Required Parts Not Included
Aftermarket Fuel Rail: A compatible aftermarket fuel rail is required. Select the fuel rail installed on the engine when ordering so JBtuned can configure the appropriate fuel-system connections.
External Fuel Pressure Regulator: A compatible external adjustable fuel pressure regulator is required for the dedicated return-style fuel system.
Different regulators use different inlet configurations, so select the appropriate regulator connection when ordering.
Fuel Pump: Fuel-pump requirements depend on the engine combination, fuel being used, injector demand, operating pressure and expected fuel demand. The fuel pump is not part of the base system unless specifically selected.
What Level 4 Changes
The original FA5 / FG2 chassis fuel system is not a conventional feed-and-return arrangement like earlier Honda chassis, so Level 4 is configured differently for the 8th Gen Civic Si.
The JBtuned Level 4 system replaces the original chassis fuel feed with a dedicated aftermarket AN feed and adds a dedicated 6AN return from the engine bay back to the fuel tank.
The result is a complete aftermarket tank-to-engine-and-back fuel-system architecture built around the needs of a modified K-Series application.
Fuel-line size, fuel type, fuel filter selection and flex-fuel sensor integration are separate configuration choices and do not change the Level 4 classification.
6AN or 8AN Feed With 6AN Return
The Level 4 system is available with either a 6AN or 8AN main fuel feed.
- 6AN Feed / 6AN Return
- 8AN Feed / 6AN Return
The return remains 6AN with either feed configuration.
Fuel-pump capability, injector demand, fuel type, operating pressure and expected fuel demand should all be considered when selecting feed-line size.
A larger fuel line does not by itself increase the output capability of the fuel pump.
350 Series PTFE - Pump Gas / E85 / Compatible Race Fuels
The FA5 / FG2 Level 4 system uses JBtuned 350 Series PTFE fuel hose for both the feed and return plumbing.
350 Series PTFE is appropriate for:
- Conventional pump gasoline
- E85 and ethanol-based fuels
- Compatible race fuels
- Gasoline builds that may move to ethanol-based fuel later
Choosing this system does not mean the vehicle has to run E85.
The PTFE plumbing simply provides broader long-term fuel compatibility. Fuel compatibility and flex-fuel engine management are separate considerations.
E85 Compatibility Is Not the Same as Flex-Fuel Sensor Integration
The 350 Series PTFE plumbing makes the fuel system suitable for E85 and other compatible ethanol-based fuels.
That does not by itself make the vehicle a sensor-based flex-fuel system.
An ethanol-content sensor can provide real-time fuel-composition information to a compatible ECU for a flex-fuel strategy, but sensor wiring, engine-management compatibility, ECU configuration and tuning are separate from the fuel plumbing.
If you want the fuel-system plumbing prepared for a compatible ethanol-content sensor, select the Flex-Fuel Sensor Provision when ordering.
The ethanol-content sensor itself is not included with the base system.
Not sure which configuration is appropriate? Read our guide to E85, PTFE fuel lines and flex-fuel systems.
Fuel Rail Feed Location
The FA5 / FG2 complete fuel system can be configured around different fuel-rail feed locations depending on the fuel rail and engine-bay layout being used.
Select the appropriate feed location when ordering so JBtuned can configure the fuel-feed assembly for your setup.
Feed location can be especially important on turbocharged or otherwise modified engine bays where intake, intercooler, charge-pipe, turbocharger and exhaust-component placement can affect available routing space.
If you are unsure which feed location is appropriate for your combination, contact JBtuned before ordering.
Optional Fuel Filter
A fuel filter is available as an option for the Level 4 system but is not included with the base kit unless selected.
Select the appropriate filter option when ordering if your fuel-system configuration requires JBtuned to incorporate the filter into the complete fuel-line layout.
Fuel filtration should be selected as part of the complete system rather than considered independently from the fuel pump, injectors, fuel being used and other fuel-contact components.
Optional Flex-Fuel Sensor Provision
The Flex-Fuel Sensor Provision configures the fuel-system plumbing around the installation of a compatible ethanol-content sensor.
This option prepares the plumbing for sensor installation. It does not include the ethanol-content sensor, wiring, controller, ECU input or tuning required to use the sensor signal.
If the vehicle will run E85 without a sensor-based flex-fuel strategy, the PTFE fuel system is still compatible with E85. The sensor provision is specifically for customers who want the plumbing arranged around ethanol-content-sensor installation.
Fuel Pump Hanger Upgrade
A complete aftermarket feed-and-return system requires appropriate connections at the fuel tank.
The available fuel-pump hanger upgrade allows the tank-side system to be configured for the selected aftermarket feed-and-return plumbing and fuel-pump combination.
Select the appropriate hanger and fuel-pump configuration when ordering if the vehicle has not already been converted for the complete aftermarket fuel system.
High-Heat Sleeve Option
Fuel-line routing on modified FA5 and FG2 engine bays can place the plumbing near headers, turbochargers, downpipes and other high-temperature components.
An optional high-heat protective sleeve is available for applications where additional thermal protection is appropriate.
The sleeve is an additional layer of protection and does not replace proper fuel-line routing and adequate clearance from exhaust and turbocharger components.
Factory Under-Car Fuel-Line Clamps
The FA5 / FG2 installation makes use of modified factory-style underbody line-retention points and plastic clamps as part of the chassis routing.
Because these vehicles are now approaching or exceeding two decades of service, inspect the original plastic retainers carefully before installation.
Factory plastic components can become brittle, cracked or damaged with age and should not be reused if they can no longer securely retain the fuel lines.
Verify that every under-car fuel line is fully supported after installation and cannot contact moving components, sharp edges, exhaust components or areas where road debris may cause damage.
EVAP / Emissions System Considerations
Some FA5 / FG2 fuel-system configurations use underbody space associated with the factory EVAP / emissions plumbing for the aftermarket fuel filter, ethanol-content sensor or related fuel-system components.
Depending on the options selected, the factory EVAP system may need to be removed or reconfigured to provide the necessary installation space.
Review the configuration of the specific vehicle before installation and account for any emissions-system changes required by the selected fuel-system layout.
Vehicle Fitment
- 2006-2011 Honda Civic Si FA5 Sedan - USDM
- 2006-2011 Honda Civic Si FG2 Coupe - USDM
This system is not designed for the Honda Civic Type R FD2.
Final fitment depends on the fuel rail, fuel pressure regulator, intake manifold, fuel pump, turbo system, exhaust components and other modifications installed on the vehicle.
If your combination is unusual or your components are not represented in the available ordering options, contact JBtuned before ordering.
Ordering Options
Fuel Rail: Select the compatible aftermarket fuel rail installed on the engine. Different rails require different connection configurations.
Feed Line Size: Choose either a 6AN or 8AN main fuel feed. The dedicated return remains 6AN.
Fuel Rail Feed Location: Select the feed location appropriate for the fuel rail and engine-bay configuration being used.
Fuel Filter: Add the appropriate fuel filter option if you want the complete system configured with an inline filter.
Flex-Fuel Sensor Provision: Select this option if you want the PTFE plumbing configured around a compatible ethanol-content sensor. The sensor and required electronics are not included unless separately purchased.
Fuel Pump Hanger Upgrade: Select the appropriate hanger configuration if the tank-side system has not already been converted for the aftermarket feed-and-return plumbing and fuel pump being used.
Fuel Pressure Regulator Connection: Select the inlet configuration required by the external fuel pressure regulator installed on the vehicle.
High-Heat Sleeve: Add protective heat sleeve where additional thermal protection is appropriate for the engine-bay layout.
Level 4 - “I Want to Replace Everything”
The FA5 / FG2 Complete PTFE Fuel System follows the same JBtuned Level 4 architecture used across the complete fuel-system lineup.
For the 8th Gen Civic Si, that means replacing the original chassis fuel feed and adding a dedicated aftermarket return to create a complete tank-to-engine-and-back feed-and-return system.
You are here: Level 4.
Feed size, fuel type, filter selection and ethanol-content-sensor provision are configuration choices within Level 4 rather than separate fuel-system levels.
Installation Notes
- This is a complete aftermarket fuel-system installation from the fuel tank to the engine bay and back.
- The original chassis fuel feed is replaced and a dedicated aftermarket return is added.
- Inspect all factory underbody clamps and retainers before reuse. Brittle, cracked or damaged components should be replaced.
- Depending on the selected filter and sensor configuration, the factory EVAP / emissions plumbing may need to be removed or reconfigured.
- All fuel lines must be securely supported and routed away from exhaust heat, sharp edges, moving components and areas where road debris or abrasion may damage the hose.
- Turbocharged and other high-heat applications require additional attention to line clearance and thermal protection.
- After installation, pressurize the fuel system and carefully inspect every connection for leaks before starting or operating the vehicle.
Fuel-system changes, fuel-pump changes, injector changes, fuel-pressure changes, fuel changes and ethanol-content-sensor integration may require appropriate ECU configuration and tuning.
Professional installation and tuning are recommended where applicable.
For off-road use only.
Questions About Your FA5 / FG2 Fuel System?
If you are unsure which configuration is appropriate for your build, contact JBtuned with your vehicle, fuel rail, fuel pressure regulator, fuel pump, fuel being used, engine-management system and approximate power goals.
