Download and install the “Gorilla FCU” application from the Android or Apple store and turn on Bluetooth. The first time you start, you will be asked for permission to use Bluetooth (Android and iOS) and for the coarse location permission (Android only, mandatory for using Bluetooth from version 6.0 onwards). 2. After accepting the permissions, you can press the “Connect” button and choose your peripheral. 

Keep in mind the name it shows so you don’t get confused when other Gorilla FCUs are nearby.

Remember that on Android and iOS the device name is different. By clicking on the name of the device we could connect to it.

In the images below you can see how Android and iOS recognize the same GorillaFCU.


THE INTERFACE With the control unit powered (LIPO 2s), after connecting in a few moments you will receive a notification “Settings readsuccesfully”: this means that the connection was successful and that the application can read the values of the control unit.

You can then start with the setting.

REMEMBER TO DISCONNECT when done to avoid more power consumption on FCU.

1: Name with which the preset will be saved: Preset means a configuration file in which all the values of the FCU parameters arepresent, at the time of saving. It is very useful if different settings are used depending on the occasion, for example for high ROF, or for maximum precision in DMR and change them in an instant without having to set value by value individually.

2: By pressing this button, you will save the current configuration with the name you set in step 1 and read it on the button itself.

3: Here are all the saved presets. Selecting one, the application will show the values saved in it, which can be sent by pressing the Write button (2). If all goes well you will receive a notification: “Settings written succesfully!”.

4: Once you have selected a preset by choosing it from list 3 (empty if there are no saved presets), you can make changes to it, and if you want to save them just click on button

4. Above it you will read the name of the preset that will be updated with the changes made.

5: Delete the preset written on it.

6: This value is very important as it tells the control unit how many solenoids are used in the HPA system: 0 for single solenoid systems (jack, N7 etc.) 1 for double solenoid systems (Polarstar Fusion Engine or F2) By scrolling the bar you can select the value concerned WARNING: by setting the value 0 the settings 7,14,14a,16,16a will not be taken into consideration by the control unit because the mounted system does not support them.

7: Allows you to select the firing sequence, where: 0 = stands for Open bolt 1 = stands for Closed bolt With the Open Bolt selection, the order of operation of the system is this:

Nozzle Dwell => Nozzle Delay => Poppet Dwell => Poppet Delay in

Closed bolt the order is this: Poppet Dwell => Poppet Delay => Nozzle Dwell => Nozzle Delay

In the following paragraphs we will better explain how to set these values.


8: This function, if enabled, will cause the control unit to stop working once it reaches the set number of strokes and to resume, hold the trigger for 3 seconds.

This allows you to simulate mid / low cap magazines even if magazines with higher capacities are mounted underneath, moreover if set the real capacity of the assembled magazines you will avoid shooting empty.

PLEASE NOTE: with value 0 the function is disabled.

9: The set value indicates how many shots will be fired with a single trigger pressure, when you are with the single shot selector.

If the value is 0, the parameter is disabled.

10: The set value indicates how many shots will be fired with a single trigger pressure, when you are with the selector in full auto. If the value is 0, the parameter is disabled.

11: Although often unnecessary with a well set replica, it may sometimes be necessary to set a higher poppet dwell value to overcome static friction. Static friction is a physical phenomenon that causes the first bullet to be fired after a period of inactivity and comes out with lower powers.

If you notice that after a few minutes of inactivity the first bullet finds it difficult to be fired, or comes out weaker, it could be the fault of the static friction.

The value set in 11 indicates after how many seconds of inactivity the value 12 will be added to the first shot (and only to the first!), so as to overcome the greater initial inertia. If 11 is 0 both 11 and 12 are disabled.

12: 12 is the value that will be added to the value 13,13a (SEMI and AUTO Poppet Dwell) in case 11 is different from 0 and the time set in 11 by the last shot has elapsed.

IMPORTANT: the values 12,13,13a are expressed in tenths of a millisecond, while the values 14,14a,15,15a,16,16a are inmilliseconds.

From 10 March 2020 the values 13,14,15,16 are been spitted in 13a,14a,15a,16a. The first one are being used when fire selector is on SEMI position, while the other are for position AUTO. FCU before this date can only use “SEMI” values that will be applied also on AUTO side. Writing AUTO values will make no change.

Update FCU firmware to have all new features working.


13: The values 13 and 13a (SEMI and AUTO Poppet Dwell) are among the most important, and indicates how many tenths of a millisecond the solenoid will remain activated.

PLEASE NOTE: Depending on the HPA system it is “the time when the air flows to fire the bullet” (for example Polarstar F2 and Fusion) or more simply “of the time in which the pusher remains behind” (Wolverine Reaper).

It is therefore FUNDAMENTAL to know the nature of the system itself before setting it.

Guide to choose the correct value:

Starting from the simplest case in which we are in a Wolverine Reaper system, with a high value of 15 (Poppet Delay) we change the value 13 until the gun fires all the shots without missing one.

Polarstar Fusion or F2 type systems we must proceed as follows:

Starting from a high value, with the use of a chrono, lower the value in steps until you notice that all the bullets have a very similar output value. Start perhaps with large steps, to go down even of one unit at a time when you are close to the optimal value.

If you notice that decreasing this value also decreases the power, increase the value until the firing power returns to the medium range.

Correctly setting this value allows you to use the right amount of air, avoiding waste and obtaining constant firing and an increase in precision.

It is advisable never to go below 30 to avoid missed shots or various malfunctions.

14: Another fundamental value is 14 (Nozzle Dwell). Expressed in milliseconds, it indicates the time required to load the bullet

into the hop-up chamber. It is used only on 2-solenoid systems.

Its value depends very much on the loaders used, it is advisable never to go below 8 so as to avoid the risk of jamming or other charging problem. To set it down value until you notice malfunctions, from there go up to the last value you found valid for your replica.

15: It is a wait value expressed in milliseconds, a low value is useful for having higher rofs or reactivity, but often at the expense of precision. It should never be set to 0 nor too low. If the replica fails, increase this value.

It is advisable not to drop below 4.

16: It is a wait value expressed in milliseconds, a low value is useful for having higher rofs or reactivity, but often at the expense of precision. It should never be set to 0 nor too low. If the replica fails, increase this value.

It is advisable not to drop below 4.


13a,14a,15a,16a are the same things of 13,14,15,16 but on fire selector mode AUTO.

17: The value 17 is an estimated prediction of the maximum value of ROF (rate of fire) and Indicates the bullets per second that will come out of the replica in the span of 1 second. In the FCU after 10 March 2020 this value is automatically calculated from

13a,14a,15a,16a while in the older one it depends from 13,14,15,16.

18: It is the universal counter of shots fired since the control unit was installed. It cannot be reset. Useful for those who buy used products, to check their wear.

19: Indicates shots fired since the last reset 22. It can be used for various purposes, such as seeing shots shot in the last play.

20: Shows the status of the FCU. If Unlocked the parameters are modifiable, if Locked it blocks every modification until the timer expires.

21: If activated, the rifle will fire at both the trigger pressure and its release.

In case 9 is different from the value 0, the latter will prevail, shooting only the pressure and not the release, the number of set strokes.

22: RAMP feature became from paintball and let you to fire slow on SEMI mode. When firing speed increase and reach a preset threshold, the rifle will start firing on FULL AUTO mode while cadence remain the same: if it decrease, rifle will return on SEMI

mode. (ONLY ON FCU > 10 MARCH)

23: It switch the working mode between SEMI and AUTO selector: SEMI became FULL AUTO and the other way around. (ONLY ON FCU > 10 MARCH)

24: It allows you to read the values set on the FCU, at its pressure you will receive a notification “Settings read succesfully!” and at the same time, the parameters set will be shown on the application.

25: Reset the partial shot counter (19) to 0, again with the attached “Partial counter resetted!” notification.

26: Once you have made your settings you will need to press this button to save them to the control unit and make them effective.

You will have confirmation of the successful saving with the notification “Settings written succesfully!”.

27: Allows you to choose how many hours to block the FCU.

28: Upon pressing the button in question, you will be notified of the imminent blocking of the FCU for the hours selected in 27. If you accept the FCU will be blocked.



Despite an excellent ease of installation, the Gorilla Trigger Board is not a Plug & Play system and needs some minor adaptation due to the multiple diversity of each M4 gearbox (the only replica on which it can be installed).

In the image below you can see the position that the trigger will cover inside the gearbox, thus understanding the parts that will have to be removed with pliers and drill.

First of all, once the gearbox has been emptied, install the selector plate supplied in the kit. It must be reassembled inside the gearbox taking care not to lose the rubber presser that activates the switches.

The mechanical safety device must be removed or filed as needed. Once the selector plate is mounted, the board can be inserted: then remove the pre-glued double-sided adhesive film and fix it to the gearbox. It is rare but possible that for the assembly in some gearboxes the lower part of the board must be filed a few tenths of a millimeter. It can be done freely.

Once the card is installed, check the functionality of all the positions of the firing selector. If the full auto or electronic safety device does not work properly, fold the switch tab very gently until the switch is activated correctly when the selector moves.

The trigger switch is easily identifiable, while the one for full auto is the closest to the cables and the central one manages the electronic safe.



This scheme will allow you, with a minimum of knowledge, to adapt the Gorilla FCU on any HPA system if you do not want to use the Gorilla Trigger Board.

1 = Poppet Power Supply

2 = Nozzle Power Supply

3 = Trigger Switch

4 = Full Auto Switch

As for the port to power the LED tracer, the common positive is + LED. If “- NOZZLE” is connected as negative, the LED will shine for the Nozzle Dwell duration, otherwise for “- POPPET” for the duration of the Poppet Dwell. At least 14 milliseconds are recommended for optimal lighting.


To increase the durability of the control unit and to avoid damaging it, use the following precautions:

1) Use only 2S Lipo batteries

2) Do not leave the control unit exposed to the sun or high temperature for long periods

3) Keep the control unit as far as possible from water and moisture

4) Disconnect the control unit at the end of the game.

5) On standby, due to some our need, FCU will last about 10h on 380mah battery.

6) Do not use dead batteries to avoid damaging the batteries

7) Connect and disconnect the control unit connectors gently to avoid damaging or breaking them.

8) in the event of problems of various kinds it is advisable to re-read the manual in order to fully understand it, often the problems are the result of forgetfulness or parameters not set correctly.

The manufacturer undertakes to update the software and user manuals to make the service always efficient and long-lasting.