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KWA EVE-4 First Impressions


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TLDR? Great on the outside, a bit crap on the inside.


Here's a quick 2 hours of ownership first impression......




Right - to start. Packaging was fine - typical KWA fare from what I've seen of other guns in their Ronin lineup. A bag of accessories was also included which includes QD sling mounts, M-Lok rail sections, T-Handle Allen keys, and a KWA branded Speedloader. Nice touch. Being the ICE limited edition version, it also comes with a Ice-blue 120rd mid cap in the box.




The gun is fitted with a really quite excellent M-Lok vertical grip along PTS Backup sights out of the box.


Externally, it's the best plastic I've seen on pretty much any airsoft gun. Think PTS EPS stock plastic quality, but the whole gun is made of it.


It really is very nice to pickup up and hold. That is, from the pistol grip forwards.


Where it falls down is the stock. Again, it's very high quality, but much like any other PDW-style stock it is limited in terms of storage capacity (which can be mitigated to a degree with an extension) and adjustability. It only has three positions, fully closed (thus useless), fully open (which is a bit wobbly), and somewhere in between which is still a touch too short for many.


If I keep this gun (more on that later), It'll get a buffer tube and a PTS EPS Stock - much like KWA's still unreleased EVE-9.


The gun is well balanced otherwise, and the pistol grip (basically a PTS EPG) is an excellent fit for my hands.


The gun is largely ambidextrous, with fire controls, bolt and mag release on both sides. Problem is, the bolt release stopped working after the third time engaging it (and I was being gentle), so the bolt will not lock back. Disappointing to fail almost instantly. The charging handle, being up front does get in the way when holding the gun if you like to wrap your hand around the rail, but it can be easily switched to the other side to move it out of the way - so no biggie.


But what's it like to shoot?


I don't know really. I tested it briefly on a 7.4v LiPo, but the motor lacks torque and I could lock the box up quite easily. Performance was a laboured 14-15rps, trigger response not great at all. The gun sounded laboured generally and the gearbox loud (which I've heard is a trait of the v2.5 GB thus 'normal').


Ok, well, KWA themselves say it's good on 11.1v LiPos, so I switched to a 20c 1300maH 11.1v. It blew the fuse within 30 shots. *Sigh*. The trigger response was nice enough and I'm guessing a ROF of around 19-20RPS in the 10 seconds it functioned for.


Soooo.......I'm on the fence with this one. I could fix the niggles easily, swap out the motor and stock, probably sort the bolt release too - and the rest of the gun feels amazing in the hands otherwise.


But I can also send it back to the vendor before any more gremlins pop up.  


Hmmm.....watch this space.


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17 minutes ago, strykerles said:

why would a gun that size have a v2.5, shouldn't it have waaaaay too much volume?


It's KWA's marketing-speak for 'proprietary gearbox'. It uses a standard V2 cylinder. Not related to anything fitted to an SR-25 style gun.

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Ok, fuse swapped. Out of the box it ships with a 20A fuse, I put a 25A in for now.


So - performance:


Chrono: 325-328fps, pretty consistent with 2-3fps variance.

ROF (Fully charged 7.4v 1200mAh 25c): A pretty disappointing 14.1 RPS and it didn't sound happy doing it.

ROF (Fully charged 11.1v 1300mAh 30c): A very surprising 23.4 RPS.


So, the motor is obviously wound for flat out speed (and volts) and not torque.


23 RPS is a bit spicy for my tastes, I would have preferred something more balanced, giving better performance on a 7.4v LiPo. So a motor swap it is i think.

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  • 2 weeks later...

Well, first game day ended bittersweet. It made it through one game before the smell and heat from the motor/grip made be throw it in the bag and grab a spare gun for fear of doing some serious damage. The gun also started to lockup as the heat/smell got worse, so I'm guessing the motor is just...well...shit. Curiously, the anti-arching diode is absent from the motor that KWA normally fits to all their other guns.


I had an intermittent low velocity issue as well, where one shot in 20 would be noticeably quieter and the BB drops well short. Initially I thought the hop-rubber needed bedding-in, but the sound change became more pronounced. So time to check the gearbox - the stock piston is largely an all-plastic rack from what I have seen with an un-ported lump of metal for a head (which might be part of the problem).


But the first 20-30mins of game play use were glorious even with the odd low velocity shot. The ergonomics, balance and feel were top notch, and it sounded great with a slight amount of over-volumising to give a nice, but not obnoxious 'pop'. It felt snappy, very 'pointable' and was very easy to put BB's on target.


Sooo...time to sort the gremlins and say bye bye to the warranty.



The guns strip relatively easily - no harder than a standard M4, just with a few some extra screws. The mag release and ambi controls do not require removal for disassembly, they remain attached to the lower.


The upper slides off with a single pin removed at the front (M4 style), but you don't need to jiggle charging handles or dust covers, it's smooth and precise and the fit between the upper/lower is excellent. This is helped by the fact that the front pin lug on the upper is part of a metal trunion/outer barrel assembly.



The lower receiver has a removable receiver stock mount/extension, and this screws into a co-molded metal threads in the lower - clever stuff. The entire back end of the lower is heavily reinforced and in places it around 5mm thick to support the stock. That, coupled with the fact that there is no rear receiver pin hole - which is a weak point on many guns, means that I would honestly place this well above any metal-bodied gun in a similar price bracket for durability.





The hop unit is again decently made from plastic, the outer barrel on my example is nicely finished brass and I have no compulsion to replace it. The hop rubber is a split mound type, which to be fair worked well enough in the time I used it, but ultimately will be replaced with a ML/Omega combo.




I'll cover the Gearbox internals another time - but it's a heavy beast of a thing and I have no doubt the shell it as tough you will ever need. The bolt release issue I had was rectified with a slight tweak of the mock-bolt - it is quite thin metal.




I will be tackling the gearbox later, but based on a few videos I've seen for KWAs, the Piston and Piston head would be worth replacing from the outset.

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2 minutes ago, ak2m4 said:

@Speedbird_666 thanks for all the pictures and writeup, had my eye on this for a while and really love the looks and ergonomics, although give me the fixed stock version.  The PTS EPG integrated grip is nice and cheeky.  Do "standard" gearboxes fit btw?


The EVE-9 will come with a PTS EPS stock.


I doubt very much that anything other than the KWA 2.5 gearbox will fit as it's very much integrated into the structure of the body itself, shaped subtly differently to a standard V2,  and the ambi controls just will not work with anything else due to a proprietary selector plate.

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5 hours ago, Cridant said:

Hello, just wondering what 11.1 30c you managed to fit in the gun. Really appreciate if you can help.


Hello. Welcome to the forums.


I didn't manage to fit any of my LiPos properly inside the gun - I had to 3D print an extension (although Airtech make one)


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The gun has now been fully re-wired with Alphawire and a Mosfet added - found a simple (but slightly chunky) Acetech AceMOS plus unit lurking in my electronics box that I forgot I bought 3-4 years ago.



Shimming has been tweaked on the Sector and Spur gear, and sounds a bit better than before. Left the bevel as-is.


The stock motor is shit - hands down the weakest link on the gun. I am able to lock the gun up on an 11.1v and it gets really frikkin hot after a few seconds of firing. So it's got speed, but not decent torque and definitely no efficiency.


Put an SHS 16TPA Hi-torque motor in - major over-spin/double shooting on an 11.1v. Switched to a 7.4v LiPo and it seems happy enough - trigger response roughly equal to the stock motor but without any lockups, around 16-17 RPS full auto and running pretty cool temperature-wise.


So now it's very usable as-is, but I want an even snappier trigger response, so the next step is a 22TPA motor on an 11.1v. Hoping to keep it around 17-18 RPS, but with the extra torque for semi-auto.


Edited by Speedbird_666
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  • 1 month later...

Final update.


The gun now has a Franken-Torque motor with approximately 28TPA - using a SHS High Speed neo magnet can, with a G&G Combat Machine 18k Armature, end bell and pinion.


It was absolutely superb all day today playing semi-only at UCAP Valiant. It shot accurately (still running the stock hop rubber), consistently, with an excellent trigger response and it never skipped a beat.


Power consumption (and heat) was massively reduced compared to the stock motor and it was pretty efficient on batteries - 2x 1300Mah 3S LiPos were used - I changed midway through the day as a precautionary measure.


It's genuinely my favorite gun at the moment - the bigger EVE-9 is definitely on my to-buy list now.


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  • 4 months later...

I see you state the polymer is PTS EPS quality, it is in fact even better than that. it is the same polymer that Magpul uses to make Pmags and there furniture.  Considering getting one and going Bat Shit Crazy on it, installing the 3.0 gearbox and recoil system, see how it holds up. :)

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On 05/12/2022 at 17:27, BigAl said:

I see you state the polymer is PTS EPS quality, it is in fact even better than that. it is the same polymer that Magpul uses to make Pmags and there furniture.  Considering getting one and going Bat Shit Crazy on it, installing the 3.0 gearbox and recoil system, see how it holds up. :)


The upper and lower use different polymers - the lower being stiffer/harder, the upper is slightly softer and has a touch more flex. There is a slight difference in colouring and finish too if you look closely. Both are excellent quality - the best I've seen on an out of the box Airsoft gun


The bolt stop has the mag well protrusion, so if you have the appropriate KWA GB with the Cutoff electronics and associated MS120C Mags, you should be able to add the bolt stop feature onto the gun.


Luke *sort of* approves (I replaced my piston with no ill effects to date but I will keep an eye on it)




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  • 4 weeks later...

Now running this gun with a Gate Titan and 16TPA SHS motor and it's very happy with this setup.


The titan was a drop-in fit with no problems at all (once I've played with the settings) and it obviously gets rid of that Heath Robinson/Rube Goldberg proprietary cut-off lever and trigger switch.


I would go as far as saying that a Titan is pretty much a required upgrade - it solves most of the niggles that I had with the gun. It's a shame that they don't offer a pre-installed Titan Basic version for £50-60 more - it would be a far more compelling option than the £300(!) Combat Machines being peddled these days.


Then there's these coming next month - I am very tempted indeed:





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  • 1 month later...
23 hours ago, BROWNING91 said:

Have you tried fitting a buffer tube?


stocks look bit ugly imo


Yes I have - some (older style) buffer tubes fit - the receiver extension is quite long so many newer style ones won't work because the screw plate is too far forward inside the buffer tube (to maximise battery space) so you can't tighten it up. 


The PDW stock is actually pretty good with an extension. I disliked it at first but have grown to like it quite a bit, very easy/quick battery change. I'm not planning to change it now. 

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  • 1 month later...

Fuck you KWA.


Turns out that KWA Pistons are oversized compared to normal AEG pistons by a couple of MM. Luke/Negative Airsoft mentioned this in the video I posted above but I figured it would be OK.


I was wrong.


So if you replace the stock piston with common (and reasobly priced!) XT/SHS fare - don't expect it to last very long. My XT piston died on Sunday with a lovely crunch as it somehow skipped over the sector gear. Investigating the fitment of the piston on the GB rails reveal that it's entirely possible that the piston can rotate several MM on it's axis AND up and down laterally.



Three or four teeth are damaged - it doesn't look too bad in the photo but you can feel it when you run a nail over them - and the piston has dozens of stress fractures where the rack flexed over the sector gear.


If you subscribe to Luke on Patreon - you will see that he now has several videos (not on YouTube) about KWA guns.


Seems like there's also a tappet timing issue with some guns if you use 11.1v LiPos - causing huge power drops once things (like the tappet spring and plate) start to wear. Slowing the gun down with a 7.4v LiPo will see the power return - but that's a shit solution to a design flaw. Negative Airsoft is now adding a brass spacer to pre-load the tappet spring, removing the delayer chip, and cutting the tappet plate (DSG style) to speed up the forward nozzle movement. I will probably take the same route pre-emptively.


Luckily he mentions a fix for the Piston in the shape of the Madbull PX02 - which is a near match for the stock piston in size. Problem is - they cost nearly £30 and are hard to get hold of...😒


So coming full circle - do I recommend this, or any other KWA gun?




No I do not.


Steer well clear.


Or be prepared to spend a shit ton of money:


£244 - Base gun

£32  - replacement Motor (SHS)

£110 - Gate Titan (yeah - I would say it's a pretty essential purchase for this gun because the stock switch/COL is terrible and impossible to get spares. No, Gate Asters or Peruns do not work without some sketchy modifications - the GB was built specifically around the Gate Titan)

£7 Piston Head (XT)

£30 Madbull Piston


Total Cost (so far) - £423










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  • 2 months later...
4 hours ago, BROWNING91 said:

mine is working fine and I’ve only swapped out the hop rubber.


Cool story bro.


5 hours ago, BROWNING91 said:

if it’s not broken why fix (imo)


Did you actually read what I posted? It was broken.


Particularly the post first game use report - where the gun ran so hot it became unusable, the weird velocity issues and the trigger switch that was in self-destruct mode - all of which I have fixed.


One look on the KWA Owners group will show that the stock piston is one of the most common points of failure and the first thing replaced - sometimes within a couple hours of use. Then there's the massive tappet-timing issue that will cut the power output in half as the nozzle and tappet wears.


I'm glad yours is working fine. There have been plenty that haven't - right out of the box.


I stand by what I've said - not recommended. At all.


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  • 3 weeks later...

Hi there @Speedbird_666,


Really detailed thread! I just purchased a KWA eve 4, which has the following upgrades:


Maxx hop up

Gate titan II bluetooth

CNC adjustable trigger


I've noticed the stock motor and batteries are running hot on both 25 and 30c 11.1v batteries, do you think it's worth swapping out the motor first and what would you recommend? Would this be too much torque / speed: https://www.ak2m4.co.uk/xt-high-torque-motor-28tpa-long-fan


I haven't quite decided on whether the Piston and Piston Head is also worth upgrading at this point too. 


Many thanks!

Edited by zknightzero
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10 hours ago, zknightzero said:

I've noticed the stock motor and batteries are running hot on both 25 and 30c 11.1v batteries, do you think it's worth swapping out the motor first and what would you recommend? Would this be too much torque / speed: https://www.ak2m4.co.uk/xt-high-torque-motor-28tpa-long-fan


I haven't quite decided on whether the Piston and Piston Head is also worth upgrading at this point too.


Hello there - welcome to the forums.


28TPA works fine in my testing - runs much cooler and draws less amps. You will get a slight full-auto ROF reduction though - which is no bad thing with the tappet timing. The extra torque shouldn't be an issue with the stock gears.


I would recommend replacing the Piston and Head. The all-plastic pistons don't seem to last long - a common complaint with KWA guns.


Gate Titan II - make sure you have the latest firmware as there has been issues with the way that the Titan II (but not the original Titan) 'sees' the sector gear teeth in the firing cycle with the additional sensor fitted on the board.





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Thank you for the welcome, would you suggest any other motor to keep the ROF up? I understand that there's a trade off with ROF / Torque and that the gears would likely be the change if I wanted to increase the ROF.


Ironically I bought a warhead 52k motor but this seems to have chewed up another build of mine that's in the shop since I messed it up, so I'm afraid to throw it in this build.


I'll purchase a madbull px02 and ZCL piston head: https://www.ak2m4.co.uk/zci-piston-head-double-oring?search=Piston


Thank you for the suggestion, I'll ensure I keep the firmware up to date. 

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39 minutes ago, zknightzero said:

I'll purchase a madbull px02 and ZCL piston head: https://www.ak2m4.co.uk/zci-piston-head-double-oring?search=Piston


Currently out of stock on the single oring aluminium piston heads - more arriving end of the week. 


Really Double O-ring piston heads aren't worth the added cost in reliability and bring nothing to the table.  Will remove this from the website just reminded me.


The POM-H piston heads with the Viton orings are currently the most requested / purchased right now so worth checking out

XT Piston Head (6 Vents POM)


Also I'm not sure about the Madbull PX02, generally a lot of retailers are pulling away from the wide rack design due to it causing scratches on the inside of cylinder.  Not sure if that type of piston is a requirement for that KWA?  £20+ for a wide-racked MIM piston doesn't make much sense to me unless it's a compatibility thing.

Edited by ak2m4
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