Toy gel Blaster JJ SLR V4 GSL V2 Gearbox Upgrade With A T238 V1.7 ETU

Hello.
Thought some Gel Blaster users out there might benefit from seeing the challenges I faced fitting an electronic trigger unit to my GSL V2 gearbox.
This wasn't as straightforward as I'd hoped, but at the same time wasn't necessarily difficult either once I figured out what I was going to do.
If you find this video helpful please do let me know and I'll document more of any future changes I make
Where I purchased the items;
T238 V1.7 ETU; www.highpressu...
JJ SLR V4; akgelblaster.c...
GSL V2 Gearbox; www.blastermas...
Ian Contessa
www.coolice.co.uk

[@drewmurray6480]

For the price the t238 stuff is awesome value and i brought 4 of the same units for $50ea from a shop closing down and love em and am spewing that they only had 4 left and silver tape works better than the selector plate stickers and lasts longer

[@CooliceChargeCases]

@drewmurray6480 Hey buddy. Yeah at their price point the T238 gear looks good. I'll be honest this V1.7 ETU has failed on me after 1.5 months, the side that controls the magazine motor isn't functioning properly and just keeps the motor running. It changes tone as you insert a magazine, but keeps it powered. From what I've read this isn't the typical failure point of these boards, it's usually the Mosfet that fails. It's currently back at HPA UK who aren't really keeping me updated, so I think I'm going to get a refund and move on. Sha,e as these are cost effective, but I wasn't expecting a failure this quickly and being a casual back garden user, it's worse as I'm not a regularly using it. Problem is the next step up to a Perun or Leviathan isn't cheap, but maybe there's a reason for the price difference. Might try again with a T238, but probably their BT one to try a completely different board design. Ian Contessa

[@drewmurray6480]

@@CooliceChargeCases leviathans are expensive but are the best in my opinion, i got 2 v2's and they were like $200aud and the optical leviathans are now available and $250aud so the most expensive but basically unkillable

[@CooliceChargeCases]

@@drewmurray6480 Hey Buddy. Sorry for the slow reply. Yes indeed, it does seem Leviathans, Titan(?) and Perun are the ones to go for if you want the best ETU's. Definitely the warranties seem longer on them which indicates the companies are more sure of their reliability. I got the refund on the first T238 V1.7 ETU and have just taken delivery of the 2nd I ordered from Aliexpress this time, as it was on a deal and much cheaper. I have seem a slight change in the main PCB shape, one of the cut outs is different compared to this one in the video, so I am hoping it is a later revision. I'm going to grab another short video I think and post it, as it could be interesting again. Ian Contessa

[@robinrahid]

I use this jj slr v4 stock right now , can you suggest some modifications for this beauty ?

[@CooliceChargeCases]

Hey Buddy. Sorry for the slow reply. I will try to, I am still new to this gel blaster scene myself but have pick up a few good tips along the way. First mod always suggested is to replace the stock piston O ring with a green one, having done this on mine I can certainly hear there is a bit more power behind the gels as there is now a tighter seal around the piston reducing air lose. Another one is the nozzle assembly at the front of the cylinder, with two O rings sealing it to the cylinder itself and an O ring in the moving nozzle itself, again you lose less air meaning more to push the gel ball out. The steel blow-back plate is a must if you want to retain this feature, I had one ready to fit but didn't until I swapped out the gearbox for the GSL. Glad I did as the pin on top of mine, the classic failure point it seems, had broken off. This stronger metal part fixes this problem. A spring upgrade is your next option if sticking to the stock gearbox, I was recommended to get he Ausgel 1.18, as it is a little more powerful without going so far as to stress the gearbox. I never got to try it as it doesn't fit the GSL gearbox and so is currently for sale through my eBay account lol. You could look to change the motor, but I don't think I would do this with the stock plastic gearbox personally. When I took my blaster apart I noticed some silver metal shavings around the casing, not having opened it up to look I can only assume it is coming off the gears, so I wouldn't like to have pushed them anymore with a faster & more powerful motor. This GSL is a a good upgrade, their prices have dropped lately and so they make a good option if you only want to go a little higher up the performance ladder. It has been pointed out as these are cast aluminium they to have a limit before they can break, so for the ultimate setup a CNC machined gearbox is best. This T238 V1.7 ETU has failed on me, not in the usual way with the main Mosfet failing, but in the magazine priming section. For some reason it now won't stop working the magazine motor, it was fine but then mid way through a magazine it just kept the mag motor running. T238 have not replied to my email after HPA UK suggested I talk to them first about my issue, HPA UK have also not responded to my email last week saying T238 haven't bothered, so now I will go through PayPal I think. So if like me you might be interested in a better trigger setup, look towards the Perun and Leviathan which is what most people recommend. So far the T238 motor I've got and I went with their 2520Kv 28000 rpm blue color brushless motor seems ok and I've read is made by Solink, so that maybe proves why it works well. If I think of anything else I'll come back. Ian Contessa www.coolice.co.uk

[@draddy2444]

nicely done and well explained , what is the max spring stength that can be used on this gear box , ?

[@CooliceChargeCases]

Hey. Thanks for the compliment on the video, it is appreciated. I did try and make it easy to understand, as there isn't many other videos around to help guide others to do the same. This ETU failed sadly after just under two months, so I returned it and have now got another one in place. So far so good. Good question about the spring choices with the GSL V2 gearbox and one I can only answer based on what I can determine on this gearboxes material choice. Sadly as it is cast aluminium versus machined, it isn't as strong as the former and so I wouldn't suggest going to high up the spring tension range. Potentially for me I'd probably not risk anything over the M110 or M120 max. I'm yet to upgrade the spring on mine from the stock GSL supplied one, so have no clue what that is off the top of my head. But I'd like to try and M100 or M110 I think. Ian Contessa www.coolice.co.uk

[@draddy2444]

@@CooliceChargeCases thanks a lot for a very detailed answer my friend . much appreciated ,... :)currently i am running a nylon gearbox and running m95 in it , trhinking to 3d print a gearbox with nylon+ carbon fiber mixed for strength , which in my opinion would be able to handle m 130 or so easily .

[@CooliceChargeCases]

@@draddy2444 Hey. Sorry for the very slow reply, it's been one thing after the other lately needing attention. No problem at all you're most welcome and happy to help within my capabilities. That would be a nice challenge, I to have 3D printers here, as well as a cnc router and laser cutter, so if I spent the time designing a gearbox I could do something myself to. I have wondered if there is a 3D step file or other out there for a V2 gearbox, as that would make for a quicker starting point, but I've not gone looking i mist admit. If you do give this a go please keep me posted on your progress as it will be a good exercise. Cheers. Ian Contessa www.coolice.co.uk

[@drewmurray6480]

Add a fuse for insurance

[@CooliceChargeCases]

@drewmurray6480 Yeah good call, I have seen fuses supplied in the main power wire. Only problem is the JJ SLR stock tube isn't deep enough I think to have one alongside the 3s LiPo I'm using. I have wondered if I could make a small round PCB that the LiPo plugs into, I could then add a fuse here. But not even looked at the possibility, just had the idea of it. Ian