Model B3A — Exhaust Bypass Valve Controller Kit

Take Back Control
Click here to view the vehicle compatibility table.

Same function as our Model B3 — but made for vehicles that have only a single vacuum solenoid valve (see compatibility tab below)

$350 USD

Now available for the Alfa Romeo QF and Stelvio QF

The Model B3A controller has the same functions as the Model B3, but for vehicles with only a single vacuum solenoid valve.  You save $25.  The Model B3A Exhaust Bypass Valve Controller Kit is a complete solution that allows the user full manual control of the vehicle's vacuum actuated exhaust bypass valves.  It utilizes as the same components as the Model B3, but with only one connector and wiring harness cable.  The user can manually open the exhaust bypass valves to have that classic engine sound at all speeds and engine RPMs.  Of course, you can return the operation of the exhaust valves to the car's ECU — which generally results in lower engine noise at low vehicle speeds and engine RPM.

Three Operational Modes - Using Either the Remote or a Manual Switch

The Forza Exhaust Bypass Valve Controller provides three different operational modes — all three modes can be selected using the included remote transmitter or a manual On/Off switch.

  1. Normal Mode:  In this mode, the vehicle controls the operation of the exhaust bypass valves.  This is the stock operation. 
  2. Always Open:  Selecting this mode will force the exhaust bypass valves to the open position — and remain open.  When the valves are Always Open, you have the full experience of hearing your engine exhaust at any time.  
  3. Always Closed:  Selecting the Always Closed mode will force the exhaust bypass valves to remain closed at all times.  This overrides the ECU control which opens the valves at predetermined engine and vehicle speeds.  This mode is especially useful to ensure that your vehicle is as quiet as possible.  Note: With this option, you can force the valves to stay in the closed position at all times.  This feature was added at the request of people who track their cars at locations with strict noise standards and did not want the vehicle ECU to open the valves at high engine RPM.

    Note:  The Always Closed mode is not available on controllers for the Alfa Romeo Giulia QF.

     Click for Always Closed Details

Designed for Severe Environments

Each kit is assembled using components designed to withstand the rigors of installation in the engine bay of a modern sports car.  The enclosure is extruded aluminum.  The internal circuit board will withstand the elevated temperatures that tend to exist in the engine bay of a vehicle.  The connection cables are constructed using high serviceability TPE insulated cabling rated to 105° C.   Connectors are weatherproof automotive connectors to resist moisture.

Plug-and-Play  ... 100% Reversible

The kit is completely plug-and-play.  Power for the controller comes from the existing connector to the car's exhaust bypass vacuum solenoids, and no wiring modification are required because the kit includes connector cables for the vacuum solenoids.  Since no modification are required to install, if you ever want to remove the controller the installation is 100% reversible.

Simplified Installation

Installation is straight forward.  You only need to select a location to install the controller, unplug the vacuum solenoids,  connect the included cables and route the cables to the controller.  The new smaller size is easier to fit in the confined space on many cars.  Once installation is complete, you use one button on your remote transmitter to open the exhaust bypass valves and the other button to close the valves and return control to the car  ...  and, you also have the ability to configure a manual on/off switch that you can mount inside your vehicle.

The controller includes one Remote Control Transmitter.  Additional transmitters are available.

 Click for Transmitter Details


  • Description
  • Additional Views
  • Compatibility
  • Compare to Others
  • Warranty
  • Completely self contained controller box
  • User configuration to use either the remote control key fob or use a manual on/off switch
  • Approved by FCC, CE and all international governing bodies
  • Always Closed option can be used to keep the valves closed at all times
  • All internal components integrated on Printed Circuit Board for higher reliability
  • Fail safe mode ... when vehicle ignition is turned off, exhaust bypass valve control reverts to factory ECU
  • No Check Engine Lights (CEL) or Diagnostic Test Codes (DTC)
  • Cables assembled using water and oil resistant flexible cord - 18 AWG stranded Class K copper conductors per ASTM B-174. Cable is rated SJEEOW for severe outdoor service with TPE insulation rated to 105° C. Type SJEOOW cords are ideal for flex applications in harsh high temperature environments where highest degree for water and oil resistance and extended service life are essential.
  • All electrical cables use weatherproof connectors
  • High-gain external antenna for improved remote control performance
  • Kit includes full installation instructions
  • Kit includes one remote control transmitter ... additional transmitters available at $10 USD each
  • Remote control can be programmed to newer versions of HomeLink (version 5 and higher) that is integrated into many cars.   Older versions of HomeLink (earlier than 2013) will not support the 433MHz frequency of the remote transmitter used by Forza.
  • Mounting accessories including cable ties and high temperature tolerant adhesive mounts

The new model of the Exhaust Bypass Valve Controller includes indicator LED on the side panel to ensure correct electrical polarity of the connection cable.

Connection cable is assembled using high grade UL listed SJEEOW cables.  The outer jackets and wire insulation is TPE insulation that is water and oil resistant and designed to withstand constant exposure to temperatures as high 105° C.

One remote control transmitter is included with the kit.  Additional remotes are available for $10 each.  Click here for additional details.

To help you install the controller module, we include some 3M Dual Lock Reclosable Fasteners. Dual Lock can be compared to Velcro ... but with a difference. Dual Lock provides very high tensile and sheer strength in temperatures up to 105° C.   Applied correctly, it makes mounting of your controller easy and secure.

The kit is compatible with vehicles having exhaust bypass valves controlled by a single vacuum solenoid.  Some vehicles may have usage precautions, contact us for more information.  Some vehicles may have differences in their electrical connectors to the vacuum solenoids, again contact us if you have any questions.

The following vehicles have been validated for compatibility. Note: The Lamborghini's require adapter connectors.

  • Alfa Romeo Giulia QF
  • Audi RS4. Other Audi call for details
  • BMW with dual-mode exhaust (call for details)
  • Ferrari F355 – click here for additional details
  • Ferrari 550
  • Ferrari 575M
  • Ferrari 599 GTB
  • Ferrari 612
  • Ferrari California (normally aspirated)
  • Lamborghini Avantador (require adapter plugs)
  • Lamborghini Gallardo (require adapter plugs)
  • Maserati - All models with exhaust bypass valves
  • Porsche - All models with vacuum actuated exhaust bypass valves

Based upon known design parameters, the following vehicles should also be fully compatible.  Contact us for the latest information or if you have any questions.

  • BMW 330, 335i, 535i and other BMW's with vacuum actuated exhaust bypass valves. The BMW 335i vacuum solenoid valve is positioned in same location as the 135i. See details on the Vehicles Install page.
  • Ferrari 550

We are currently engaged in verifying functionality and compatibility for other vehicles. Please contact us if you do not see your vehicle in our compatibility listing.

The following table provides a full detailed description of the Forza Model B2A Controller.

There are other after market devices or controllers to manage the exhaust bypass valves on various motor cars.  We believe that the Forza exhaust controllers are the best that is available and are superior to others.

The Forza unit is custom manufactured for the job and all components have been designed for long term reliability.  It costs more to manufacture, but we are keeping our price very competitive to assure total satisfaction.  The Forza unit is completely plug and play.  It is ready to install out of the box and no modifications are required to install it on any vehicle.

The table below provides the full design details for the Forza Model B Exhaust Controller


Forza Model B Controller

Controller Material Aluminum

Able to sustain high temperature conditions that are present in an engine bay.

Other controllers typically use ABS plastic that does not stand up to heat as well as aluminum

Controller Module Configuration Manual switches located inside controller module

Installation accessories included Yes
Max temperature recommended for installation location 105 °C

Higher temp has no effect on enclosure, but could affect internal components
Control Cable  Construction Automotive four conductor cable with high flex TPE insulation on wires and cable jacket rated at 105 °C

Cable rated for hard-usage applications, water and oil resistant and other harsh environments.

Competitive products typicall utilize loose wires contained within a braided or coiled nylon sleeve. Protection from elements is minimal using this kind of wiring.
Weatherproof connectors Yes

Both ends of cable fully protected from dust and moisture using Tyco / Amp weatherproof connectors.

Cable connectors fully protected and sealed using weatherproof boot

Compare to less expensive nylon connectors that are not water or dust proof.
Antenna High-gain 1/4 wave external antenna

An inexpensive dangling wire is frequenly used by competitive products. Although functional, a dangling wire could be prone to breaking and will not likely provide optimum reception.
Option to use a manual On/Off switch Yes

The Forza controllers are the only ones that provide the option to use either the included remote or a manual switch that you could install in the cabin.
Always closed option Yes

The Forza controller is the only one to offer an "Always Closed" option.
Fail-safe mode to ECU control Yes
Number of Included Remote Transmitters 1
Controller Kit Cost The Forza controller sells for $350 versus $650 that you would pay for a controller kit of less quality and functionality.
Extra remote transmitter cost The Forza remote sells for $10 versus $20 from our competitor for the exact same remote.


The controller kit is warranted to be free of defects. If the controller should fail within 12 months of installation, return it to us for repair or replacement.  You only need to pay for shipping to us ... we will pay for return shipping.

Returns and Refunds

Contact us for any refunds.  We will refund your full purchase price within 15 days of receiving your kit.  Just return it in the original condition ... no questions asked.   After 45 days, a re-stocking fee of 15% will be applied for any refunds.