GEN 8 Gearbox Fire Select/MOSFET Options

I’ve got a build in mind that will be an older blaster shell modified to accept a Gen 8 gearbox. The old issue of full auto only is a bit of a problem, fire select is kind of necessary.

I’m pretty slick at fabrication and mechanical modding, but a good grasp of the voodoo art of electronics always eludes me… :wink:

Is there any MOSFET / fire control solution available that works with a Gen 8? I seem to remember reading in a post on here that the Gen 8 trigger arrangement precludes semi-auto function, and that MOSFETs don’t work with them. :man_shrugging:

As an alternative, is there anything available that allows a direct motor to gearbox fitment for a V2 gearbox without the use of the handgrip?

Any advice and guidance is, as always, hugely appreciated. :+1:

1 Like

Seems very limited gear available for some reason.
The Urrkii FCU’s are no longer being produced, the Stormbreaka from RPM is out of stock and the Airsoft T238 has been designed for V2 style triggering inputs these days.
Try researching for NERF FCU’s as well, as these are easily adaptable to GelBlasters.

Almost forgot…… the original M4SS FCU’s are still available cheap…. $10, as well as all of the wiring and associated switches/plugs/contacts etc. that fits Gen8 receivers and triggers.

The hardest thing to find was the 4 position Fire Select Switch, but possibly other ways to get around this issue.

Check out EBay for all the associated parts/details, plus should hopefully still be a few videos available on YouTube to suss them out.

If not, I can easily walk you through how to set them up.

Add a tiny T238 MOSFET to the system and they are reasonably tough :sunglasses:

1 Like

Awesome info, Doc… very much appreciated. Good directions to take further enquiries. :+1: mate, for $10 it’s a no-brainer to get a couple of M4SS MOSFETs and see if I can come up with a solution.

I’d really like to go V2, solves the MOSFET issue beautifully but it’s problematic mounting the motor up internally.

Cheers for the offer of the assist… I’ll probably have to take you up on it :joy: when it comes to wiring I’m a little dyslexic to say the least.

The Airsoft T238 can be adapted for GelBlasters without the need for a separate mosfet, but is around $140 AUD and will require adapting wiring to the trigger and some type of signal pickup for the sector gear/piston.

Just found this amazing item on AliExpress. Check it out! AU$40.93 38% Off | Urrkii Airsoft Mosfet Kit G3 Programmable for Airsoft Air BB Guns AEG Electric Airsoft Gun Pistol Air Metal Rifle Tactical Part

1 Like

Weird how the link came up🤣
Can be set with semi or burst and full auto.
The TT mk3 was basically a gen8 with fire select👍

Ran them in my gen 8 converted A1 Steyrs. Used to have it set to 4 round burst. Then I figured I could do the same with trigger control

1 Like

That’s awesome mate!
Haven’t been able to find a listing for them for ages :thinking:
@Friendly_Fire …… THIS is definitely what you want!

I had a few of them and they were a very good little bit of gear :ok_hand:

Strange that can only find a couple left on a few overseas Amazon listings…… but not in stock or available in many other searches?

Only wires to connect other than the battery are the two little red/white trigger wires.

1 Like


Absolutely awesome, guys! :clap: Exactly what I need… ordered it 5 nannoseconds after I saw the link and read your comments.

Very much appreciated :blush: that’s what I love about this forum. The good oil, every time.

1 Like

Handy that they are available pre fitted with the choice of DEANS/Tamiya/XT plugs too!


Ensure you enable lipo protection first as this also helps the programming recognise amp draw etc.
Disable the active break for less motor heat.
I have used it with semi, sensitivity needs to be adjusted to get single shot perfect.
I turn the auto delay down to minimum.
Wire it in to the trigger switch as it stops the trigger switch from melting in high performance builds👍
Bonus is when used with normal semi/auto fire select gearboxes like Cyma etc. it gives you burst and auto when switched to auto on the blaster


Very cool… I’ll keep all that in mind when it arrives and I do the install. :+1: cheers, man.

Just to confirm, with a Gen 8 full auto setup with no integral fire select function, switching between semi, burst and full auto with this MOSFET means swapping modes with the trigger programming function? I’ll only be able to have one fire mode operational? :man_shrugging:

I’m half tempted to put it in something with fire select already so I can dial in burst fire on full auto… I do like my three round burst. :wink:

You can program it through the multiple inputs from your tigger.

Basic mechanical safe/semi/auto can be customised within the programme’s settings :+1:

Often wondered how does it detect between semi and auto. :thinking: haven’t tried one myself.

On a gen 8 you have to set the burst mode to a single shot. Holding trigger will switch to auto


So does it reset back to semi on trigger release or stay in full auto when you do that? :thinking:

1 Like

With a gen 8, a single trigger pull retains whatever number of gels is set for the burst mode when you release the trigger. Hold the trigger and get full auto, release the trigger and the next trigger pull is whatever is set on burst


So does that make it not able to do semi, burst and full?

Correct. If you install on blaster with switch able semi and full then you can install it with burst on auto.


If it’ll just do burst and full auto I can definitely live with that… :+1: