Browse Categories

VRFI Gen 4 System

MSRP: $1,314.95
Price: $1,084.75
You Save: $230.20 (18 %)


* denotes required field

Choose Your Model*

VRFI Gen 4 Fuel Injection Controller for 2002-2014 V-Rod™ with Delphi® System

· Quickly auto-tune fuel curves for front and rear cylinders on a dyno or on-road with new WEGO IIID dual channel wide-band oxygen sensor interface

· Fully programmable plug-in replacement for 36 pin Delphi® controller

· Robust alpha-N (throttle position and RPM based) fuel control eliminates problems with long duration/high overlap camshafts

· Powerful Windows software for custom programming and data analysis

· Full support for J1850 data bus used for communications with turn signal/security module (TSM/TSSM) and instrument cluster

· Enhanced data logging and diagnostics

· Billet aluminum housing with black anodized finish

· Easy plug-in installation

· Supports all sensors including theft/security module


VRFI 4 Install Guide
VRFI 4 Manual
VRFI 100KPA Tech Note
VRFI 300KPA Tech Note

Visit the VRFI Tech FAQ for more detailed information about using the TCFI in performance applications!

VRFI Software Download
USB Driver


The VRFI is the V-Rod™ version of our proven TCFI fuel injection system for Twin Cam applications.

The VRFI kit includes the new WEGO IIID dual channel wide-band exhaust gas oxygen interface that allows quick auto-tuning on a dyno or on-road during actual riding conditions. The kit includes Bosch LSU 4.2 wide-band sensors for both front and rear cylinders. The user programs a table with the desired air/fuel ratios - the system then does the rest.

The VRFI solves tuning problems with highly modified engines. Competitive “band-aid” products that interface to the Delphi® controller still rely on speed-density fuel control. Long duration/high overlap camshafts wreak havoc with manifold pressure - especially at idle and cruise RPM. Speed-density based fuel control simply can’t cope.

High-end automotive racing systems use alpha-N (throttle position and RPM based) fuel control. Alpha-N eliminates any dependence on manifold pressure and is unaffected by long duration/high overlap camshafts. The VRFI brings this proven technology to the H-D® marketplace.  

Unlike competitive "band-aid" products that only control fuel delivery, the VRFI allows complete control over all engine functions, including ignition advance, idle RPM and cold start characteristics. This facilitates the use of throttle bodies modified for higher airflow.

All V-Rod™ motorcycles use the SAE J1850 data bus for communications between the engine control module (VRFI), instrument cluster, and turn signal/security module (TSM/TSSM). The VRFI fully supports this new J1850 data bus. The VRFI also has built-in data logging that stores data for the last 60 minutes of operation at 10 samples/second. A USB interface and Windows compatible software allow the use of a laptop PC for programming and data analysis. The USB interface plugs into the existing H-D® diagnostic connector on the motorcycle wiring harness. 

The VRFI is intended for high performance race engines. We provide setup tables that will get you up and running. From a practical standpoint, tuning any fuel injection system requires an exhaust gas analyzer. You can either spend a lot of time on a dyno with an exhaust sniffer (like the newer Dynojet units) or you can use our WEGO. With the WEGO, the system will auto-tune the fuel tables while you ride the bike - you won't need to spend any time on a dyno. Auto-tuning under actual riding conditions only takes a few hours and gives much more realistic results that dyno tuning.


Wide-Band Oxygen Sensor on Front Pipe


Wide-Band Oxygen Sensor on Rear Pipe 

PC Link Software for Programming Custom Advance and Fuel Tables

PC Link software runs under Microsoft Windows XP/Vista/7/8. We no longer support older Windows versions. PC Link allows the user to program all the engine control tables and parameters within the Twin Tec VRFI system. Minimum PC requirement is a 300 MHz Pentium with super VGA display (SVGA with 1024 x 768 pixel resolution). The VRFI connects to the PC by means of a USB interface. A USB cable is supplied with the unit. The PC must have a free USB port.

3D tables are used for ignition advance and fuel control. Additional 2D tables are used for functions such as cold start enrichment and idle air control. Some sample tables are shown below. 


Sample 3D Ignition Advance Table


Sample 3D Air/Fuel Ratio Table


Sample 2D Idle Speed Table



Sample Engine Control Parameters Screen


The VRFI also features a user input and user output that can serve various functions. The user input can be configured for data logging (such as the status of a switch), ignition retard, ignition kill (for air shifter), or stage RPM limit. The user output can drive a relay and be configured as a general purpose RPM and throttle position based switch or to trigger an NOS system.  

User Functions Screen

PC Link software is free! You can always download the latest version of the software and instruction sheet from our website. The software will run in demo mode without a VRFI system attached. For your convenience, we include a copy on CDROM when you purchase the VRFI system. 


VRFI Data Logging Software

The VRFI features comprehensive data logging capability. During dyno testing, you can display real time engine data on an instrument panel type screen. The VRFI also stores data for the last 60 minutes of operation at 10 samples/second. You can download and display this data on a chart recorder type screen. Data is available for all sensor inputs and output functions. The VRFI data logging capability greatly facilitates fine tuning and diagnosis of driveability issues. The data logging software, VRFI Log, has the same PC requirements as described above for  the PC Link software. For more detailed information, we suggest that you download the VRFI Log software and instructions. The software download includes a sample file with actual data.  

Real Time Engine Data Display


Data Logging Chart Display

The data logging software also allows you to download operating statistics and historical diagnostic codes.  Downloaded operating statistics are displayed as shown below. Total hours represents the total time that the engine was running. ID represents the firmware identification. This field typically includes the manufacturer (Twin Tec), model number, program revision and author's initials, and date. Elapsed time is displayed for 10 RPM bands from zero to 9,999 RPM. The utility also displays the maximum engine RPM, time at the RPM limit (in seconds for better resolution) and the number of engine starts. All this data can be printed to provide a permanent record. The data stored in the module for maximum engine RPM and time at the RPM limit  can be cleared. All other elapsed time and engine starts data is permanent. 

Any historical diagnostic codes logged by the VRFI are listed along with the number of trips (engine start cycles) since the individual code was last logged. The software can also clear diagnostic codes. 


Operating Statistics Data


The elapsed time data in the various RPM bands can be displayed in the form of a histogram chart by clicking on the Histogram button. Clicking on this button causes the chart shown below  to appear. Color coding of the bars helps to interpret the data. The idle RPM band is blue, normal operating RPM bands are green and high RPM bands are yellow and red. The chart is automatically scaled for best display.  


Operating Statistics Histogram Chart


VRFI Log software is free! You can always download the latest version of the software and instruction sheet from our website. The software will run in demo mode without a VRFI system attached. 

Related Products

Desktop Power Adapters
MSRP: $112.95
Price: $93.75
You Save: $19.20 (17 %)
Desktop Power Adapters
Power Adapters (12 volt power supply for bench top programming of all TCFI/VRFI and Ignition systems. 110-240 VAC multi-plug international compatibility)

Product Reviews

(0 Ratings, 0 Reviews)