I need some ideas for upgrades

[ModernTimes]

After changing my motor and spring I realised I messed up and did some stupid upgrades because I thought bigger spring bigger motor means better but it doesn't. I'm back to correct the problems now that summer is coming but I need some advice first.

I have a SA-C08 CORE and I am in the process of installing a X-ASR MOSFET. This is ongoing right now so this is where I am.

I'm looking for a higher rate of fire, faster trigger response time and further distance shooting within limits. What are upgrades I can do that would give me the best bang for the buck to get what I want?

 

[Cannonfodder]

The easiest way to increase rof and speed up trigger response is to simply use an 11.1v lipo battery (assuming you're using a 7.4v now) however this may cause over spin.

To increase range you're best option is to change your hop unit as higher muzzle energy does not equal better range.

 

[Rogerborg]

I have a SA-C08 CORE and I am in the process of installing a X-ASR MOSFET.

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The X-ASR just does trigger protection and (maybe) allows for more current slow. However, it also likes to pet its lip if you are running a meatier motor and spring.

Something like a Perun AB++ gives you far more features.

I'm looking for a higher rate of fire, faster trigger response time

Motor and/or run 11.1V.  I like the Big Dragon M140 as a decent improvement over stock motors for not a lot of money when bought direct from Ali Express.

and further distance shooting

Heaver BBs, clean the barrel and maybe fit a Maple Leaf bucking (e.g. 60 yellow) and omega nub.

The stock M90 spring in the Specnas can benefit from being swapped out for something stronger, but air seal uber alles, and I'd always recommend buying a chrono first before doing anything that might effect the muzzle energy.

 

[ModernTimes]

rof and speed up trigger response is to simply use an 11.1v lipo battery

Will purchase one later today. Currently have 7.4v's.

best option is to change your hop unit

Aren't they expensive? I have also read online that the stock one is good and the upgrade would be as minimal as changing the barrel.

Something like a Perun AB++ gives you far more features.

I already made the purchase years ago so I will try it out anyways. Perun AB++ is £48.00 so want to avoid if I can to keep costs low.

fit a Maple Leaf bucking (e.g. 60 yellow)

Ordered. On its way already.

buying a chrono first

Ordered. On its way already too.

Big Dragon M140 as a decent improvement over stock motors

You recommended me this 2 years ago haha. I'll do some testing to see the difference once the chrono arrives.

 

[Lozart]

Aren't they expensive? I have also read online that the stock one is good and the upgrade would be as minimal as changing the barrel.

Hop units don't have to be expensive. If yours works OK and doesn't slip then keep it in.

 

[MrTea]

best option is to change your hop unit

Aren't they expensive? I have also read online that the stock one is good and the upgrade would be as minimal as changing the barrel.

I built a mk18 style AEG from a Specna Arms Core 04 and still run the standard blue plastic hop unit in it to this day and that AEG has some good range on it. The hop unit very rarely ever needs changing unless it's adjusting itself when in use. Changing the bucking & nub is all you need to do - I mostly always use Macaron 60 degree and the Omega nub.

Inner barrels are subject to a lot of arguments. Some claim that the stock brass are fine and probably just need a quick polishing. Some inner barrels are cheap enough that you can buy one and see if theres much difference. AK2M4 has his own range of inner barrels that appear to have a massively better polish/finish than the similarly priced ZCI offering.

 

[Cannonfodder]

Heaver BBs,

I can't believe I forgot that. 

 

[Rogerborg]

I have also read online that the stock one is good and the upgrade would be as minimal

The EDGE hop units are fine, I'd hope that the CORE ones are OK too - but it always depends on the example that you get.  I'd agree with just changing the bucking and nub and see how you get one. One thing at a time, to see how better or worse it gets.

 

[ModernTimes]

I'd agree with just changing the bucking and nub and see how you get one.

I'll post a comparison once the starter upgrades are complete.

 

[ModernTimes]

Update:

View attachment 127555

Added bucking and nub but not much difference.

Measured 0.23g BBs 284 FPS. Any idea what the issue could be? It is also with the dragon motor and a MOSFET now installed.

 

[Badgerlicious]

Measured 0.23g BBs 284 FPS. Any idea what the issue could be?

If you can get the fps values of a few shots in a row (5-10) to give an idea on variance, that'd help. Could be just be it being a factory m90 spring with not great air seal. A lot of variance is probably poor air seal. You should also be able to lift at least .28s, but probably .3s or .32s with that rubber. 

 

[Lozart]

Update:

View attachment 127555

Added bucking and nub but not much difference.

Measured 0.23g BBs 284 FPS. Any idea what the issue could be? It is also with the dragon motor and a MOSFET now installed.

The MR Hop rubber has a very large contact patch, if that's a stock barrel the mound inside the hop rubber might not be sitting quite properly. Have a look down the barrel and check to see that it's free to move up and down properly.

Did you order a better barrel by any chance?

 

[ModernTimes]

row (5-10) to give an idea on variance, that'd help

After replacing the spring from the default M90 to the M105 the past 8 readings are:

295.8

302.9

300.2

306.4

303.3

308.4

446.5

303.3

the hop rubber might not be sitting quite properly

I'm pretty certain I have put it on properly, I verified multiple times and its aligned with the line on the barrel and placed the correct way up. I've not ordered a new barrel yet no. Was hoping to avoid this.

To add onto this, the bb weight is 0.23g so for outdoor play, an ideal 0.28g is giving me 274FPS. I want to reach 350FPS as much as possible.

View attachment 127976

 

[Rogerborg]

I want to reach 350FPS as much as possible.

You mean you want to reach 1.13J.  I stress this because thinking and talking in terms of fps (implicitly with a 0.2g BB) is legacy thinking.  The only way you're going to get it tuned for the ideal amount of power for the BBs that you actually want to use is to test with them, properly hopped.  I know that this isn't practical for kitchen-table teching, but there's no magic solution other than going through a few iterations of actually shooting it in the field.

That said, those numbers do look low for an M105 spring, so I'd be thinking air-seal now.

This is how to test for end-to-end airseal, then if it's not perfect, you'll start working backwards to find where it's leaking.

 

[ModernTimes]

This is how to test for end-to-end airseal

View attachment 128104

Airseal is horrific. Its almost non-existent so will debug this further. Thanks for the tip. My idea thus far is maybe the piston is causing the issues.

Update (17:00)

Join between piston and the barrel itself is the cause.

 

[SSPKali]

View attachment 128104

Airseal is horrific. Its almost non-existent so will debug this further. Thanks for the tip. My idea thus far is maybe the piston is causing the issues.

Update (17:00)

Join between piston and the barrel itself is the cause.

Air seal as stock on many guns is pretty bad. Just a case of eliminating it step by step. 

Piston head to cylinder, cylinder to cylinder head, cylinder head to air nozzle (always bad with those plastic ones!) and air nozzle to hop up rubber. 

With a good air seal I have got 1.05J from an M90 spring

 

[Rogerborg]

cylinder head to air nozzle (always bad with those plastic ones!)

A smear of silicon grease can do wonders there.

With a good air seal I have got 1.05J from an M90 spring

1.3J from an M100 and a stock (but stretched-and-greased) CYMA gearbox and nozzle.  Yes, quivering on the edge of a Section 5.  The difference between nearly sealed and really sealed is remarkable.

 

[ModernTimes]

cylinder head to air nozzle (always bad with those plastic ones!)

View attachment 129451View attachment 129452

I noticed the original air nozzle is quite bad with no rubber rings inside so I bought a replacement. The issue looks to be the connection between the air nozzle, cylinder head and hop up rubber so I'll just replace this, grease up parts of hop rubber area and do some more testing.

Is there any areas in particular I should ensure I grease?

 

[Lozart]

View attachment 129451View attachment 129452

I noticed the original air nozzle is quite bad with no rubber rings inside so I bought a replacement. The issue looks to be the connection between the air nozzle, cylinder head and hop up rubber so I'll just replace this, grease up parts of hop rubber area and do some more testing.

Is there any areas in particular I should ensure I grease?

Just the o-ring inside the nozzle (or the tip of the cylinder head tube bit). If it's not mating properly with the lips on the hop rubber, your nozzle is the wrong length.

 

[ModernTimes]

Just the o-ring inside the nozzle (or the tip of the cylinder head tube bit). If it's not mating properly with the lips on the hop rubber, your nozzle is the wrong length.

Update 1:

The lubing worked great. The results for the air seal are now very consistent. Its now a solid 0.770J. With a variantion of each shot of 6+- FPS.

I replaced the spring to the more powerful spring and this took me to a whopping 320 FPS with 0.961J however problem is that the spring bends mid shots.

Any idea on how to solve this? Its clear I need a better spring now. Should I just go for a spring below the one I have now?

Actually, reading back now. I might opt to improve the air seal more and work on that.

Update 2:

Lubed up the piston. Found out through another video that piston is actually losing a decent amount of air. Going to buy a new piston set. I can hear air escaping through this when I do a seal test. It also moves way too much around to maintain good seal even with the lubricant.