XForce Varex Smart Box Bluetooth Variable Exhaust Controller




 App Store Badge US-UK 135x40    app-google-Released-icon



The renowned VAREX Exhaust System was invented and manufactured by XForce Performance Exhaust.

VAREX exhaust has since been the most popular choice among the enthusiasts and professionals, who are seeking the flexible control of the sound level for their performance exhaust.

VAREX exhaust systems allow users to adjust the exhaust sound from stock-car like quiet to sports-car like growl by a click of a key fob button. 

We love our VAREX exhaust sound and performance, and we would prefer keeping the Varex exhaust on the “Open Mode” most of the time.

However, there is always some moments, the high volume exhaust sound is less desirable. We know that it is part of the nature of most performance exhausts.

Imagine the following scenario:

When you are cruising in a beautiful stretch of country road,  slightly tapping on the throttle pedal just to maintain the cruising speed, or simply let the cruise control taking over, most likely we would hear a low pitch, slight(or loud) humming exhaust sound resonating inside the cabin.Some of us might be fine with it, but to some, it could be a little bit too much to bear, especially during a long trip.

With Varex muffler installed,we could have reached for the Varex remote key fob, and quickly pressed the button to reduce the sound level. It is a good way to go, but yet not the most convenient one.

We couldn’t stop thinking, what if we can create a device that will know when and how to change the exhaust sound for us, and do it precisely and automatically.

It will mean that this smart control system can sense the right moment, and produce the right exhaust sound for our enjoyment.

Gladly, our R&D team took up this challenge, and that was how the idea of Varex Smart Box Bluetooth® Exhaust Controller (VSBec) have been contemplated and created.

Our goal is to make the most user friendly Variable Exhaust System, and reduce the stress of  owning a loud performance exhaust.

By VAREX Smart Box, we believe that we have achieved our goal.



 Varex Smart Box is a control device with patent pending technology that let the user to manually and automatically adjust the exhaust sound level of the Varex exhaust.

The users can operate and make change to the settings of the Smart Box via an elegantly designed Smartphone App.

The connections between the Smart Boxes and the smart phones are via the latest Bluetooth® technology, which provides an exceptionally reliable and smooth user experience.

Smart Box provides the following functions:

  • Manual Mode:

    • Precise manual adjustment of VAREX exhaust valve positions; 

    • Custom pre-set of VAREX exhaust valve positions;    

  • Matrix Mode:(Only Work with Vehicles equiped with OBDII)

    • Automatic control of VAREX exhaust valve positions based on real time information of RPM,Throttle, and Speed.






Manuel Mode Video Play icon


Previously the variable exhaust valve of VAREX muffler was controlled by a key fob, something similar to a car door key fob.When user presses  the the button on the key fob, the exhaust valve will starting turning until the pressing is stopped.

The key fobs work well , but it is not perfect.

The users are not able to precisely control the valve position, and there is no feedback display of what the valve position is. Furthermore there is no memory for any pre-set valve positions.

The need for more user control of VAREX has been driving our team to design the most user-friendly and precise controlled device by far for variable exhaust , which is the Manual Mode of the Smart Box.

By Manual Mode, you can select the 5 pre-set valve positions, which are default to be  “Closed”, “25%”,”50%”,”75%” and “Open”.

It is already a huge step forward, however,we were not stopping here.

We went on to design a procedure to let our users  to set those pre-set valve positions by simply holding one of the pre-set buttons, a custom setting page will elegantly flip out for picking the desired valve position, and the newly set position will be recorded.

How easy and convenient will that be!

Also for those users who still want the touch and feel of the old key fob, we have something just for them. There are two arrow buttons on the bottom of the screen, which imitate the old key fob button operations. With much more to it, now you can see the turning progress displaying on the Smart Phone screen to indicate what the valve position is. We have to say, the operation of the valve position progress circle is such a pleasant to look at.

Furthermore, there is a good news for those customers who want to use the existing Varex key fob. The new Smart Box can be connected to the existing Varex key fob controller, and the users can operate the Varex muffler using the key fob. The beatiful thing is that the user can watch the Valve operation progress on the smartphone App while operating the key fob. The guesswork in the old days are gone, and you will always know what Valve position it is at.

We hope you enjoy the brand new experience of the Smart Box Manual Mode.

 See more information for Manual Mode  in the App User Guides.



 iphone-matrix mode-tpiphone-smart-box-New-Matrix-p2-tp


 Matrix Mode Video Play icon



In order to change the sound automatically, we need to know how to locate the sound.

There was a breakthrough finding in our research, and it intrigued us.

We can locate the sound by three vehicle parameter value ranges: Engine RPM, Throttle Position and Speed.

Based on this finding, we created the “Matrix Mode”.

We call the parameters value range the “Band”.On the Smart Phone App, we have designed a very user-friendly interface to pick the right band value. Don’t worry, we will show you how this works in the App User Guides section.However, It would be a big task for users to know what “Band value”  should be assigned.

We have just the solution for our Smart Box users.

We call it the “Band Snap” feature.

It is simple to use, even though it requires assistance from a fellow passenger.

The user can drive the car as usual, just at the moment when the exhaust sound that we want to find becomes prominent, the driver can instruct the assistant passenger to tap the “Band Snap” button within the App, the Smart Box will automatically assign a band value range for each parameter. Users can even further fine tune the band range later if needed.

Isn’t that magical?

Matrix Mode enables our users to easily locate and change exhaust sounds, and do it effortlessly!


Note: The Matrix Mode only works with vehicle equiped with OBD II port.

 See more information for Matrix Mode  in the App User Guides.





GEO Mode Video Play icon



There is always some locations that we just want the Varex exhaust to be quieter, while we don’t mind it to be loud everywhere else.

We believe that this is what Smart Box supposed to do.

We created the GEO Mode for Smart Box.

We want our users to be able to define a region on the map, and then set a particular exhaust sound for that location.
We want that to be done simply and intuitively by dragging a circle on the smartphone screen.
And it just works perfectly.
Multiple regions are allowed to be set and memorized.
Please see the easy-to-read App User Guides for further instruction.
Finally, you can go home quietly with Smart Box.







  • Smart Box Control Module x 1

  • OBDii Cable x1

  • GPS External Antenna x1


What is the price of the VAREX Smart Box?

 The RRP is $599.

 Please contact our authorised stockist/resellers to inquire about the purchase.

Where to buy?

You can purchase the Smart Box and other XFORCE products through our XFORCE Authorized Dealers.




The SmartBox controller module is designed in such a sleek and robust form that it can be easily tucked away in various tight spots inside the cabin.

OBDii Data Cable and Varex Muffler Motor Power Cable can be concealed inside the suitable inner panels, which makes the whole set-up hidden away and not being intrusive.


The module needs to be connected to the following devices

  • 12V socket via power cable;
  • Varex Exhaust Valve Motor via power cable;
  • Vehicle’s OBDii Port via ODB ii cable.
  • Smart phone * via Bluetooth® ;


  • Connect the OBDii cable to the OBDii Port in the vehicle by plugging the dongle to the port; 

  • Connect the RJ12 (Square adaptor) to the Smart Box Control Module; 

  • Conceal the cable inside suitable panels if possible;

  • Connect the power cable to the SmartBox Control Module;

  • Conceal the cable inside suitable panels or carpet if possible;

  • Connect the power cable to the Varex muffler motor;

  • Conceal the power cable inside suitable panels or carpet if possible.

  • Connect the External GPS Antenna;

  • Conceal the Externa GPS Antenna cable along the pillar trim, attach the antenna receiver on the surface of the windscreen using double-sided sticker.





  • Start the engine;

  • Open the Smart Phone App;

  • Waiting for the Smart-Phone App to connect to the SmartBox Control Module;

  • Once the connection is established, start using the App to operate or make change to the setting of the Varex Exhaust.

  • Once the setting is completed, the App can be closed or left open according to the user's preference.

  • By pressing on the reset button using a small pin it can move the exhaust valve to close and open position in sequence.

  • By holding the reset button using a small pin for longer than 10 second until the blue LED indicator flash quickly, it will reset to the factory default settings.



There are three modes in the Varex SmartBox App:

  • Manual Mode;

  • Matrix Mode;

  • Setting Mode.

 Click here for VAREX Smart Box iOS App User Guides.


iTunesArtwork2x       App Store Badge US-UK 135x40 




Use this application only when traffic conditions permit, 

and should not be used by the driver when driving the vehicle. 

Safe vehicle operation is the driver's responsibility. 



Product Disclaimer and Notes:

  • The VAREX Smart Box might not work with some of the Varex Mufflers.
  • The VAREX Smart Box might not work with non-VAREX mufflers or variable exhaust valves.
  • The Matrix Mode in the VAREX Smart Box only works when the vehicle is equiped with OBDII.
  • We will offer refund upon return of products in the original condition when sold, in the case of non-functioning.
  • The RRP is suggested to be changed without notice.


Cart 0

Shopping Cart

Your shopping cart is Empty!