High speed questions

Discussion in 'Gun Building, Modifications & Repairs' started by natethegreat, Jul 10, 2014.

  1. natethegreat

    natethegreat New Member

    782
    0
    Brighton
    My gun recently broke and its finally time to upgrade. My gun is the lonex fmg4. I have in the gun;
    Lonex red piston,
    Zci piston head,
    Lonex bushings
    Lonex trigger group
    Lonex cylinder
    And lonex a1
    So i already have some decent parts in my gun, but i am planning on putting in;
    Shs 12:1 (why not, faster than 13:1?!)
    M130
    New ph
    Lonex ch
    Shs pinion
    Nuke fet
    Goal 40rps 420 fps (.2)
    So i have some questions now, with an m130 i will get higher than 420 so if i short stroke, i can pull my fps down?! How many teeth should i take off? Also the nuke fet has tvs diode, but im not completely sure on what is does. So should i get a resettable fuse mosfet instead? Also, for a dsg, i have heard that a 14:1 is better than 10:1 because 10:1 needs added torque. Is this true? In that case could i run an 18 tpa 14:1 and it would be faster than a 22tpa 10:1? on my dsg I'm looking for 50 rps. But if a 14:1 would give me more options than a 10:1 i will do that.
    Thanks for help in advance :)




    Build the best dont buy the best
     
  2. nathan327

    nathan327 Active Member

    1,043
    9
    Near Columbus
    1. Your piston is heavy. I'd recommend that you either Swiss cheese or get a lighter one, like an SHS 15 tooth.

    2. If you plan on using an 11.1 lipo, iirc that setup should yield around 44 rps.

    3. If you are getting a new piston head, get a lonex POM or super shooter POM, ZCI has had some manufacturing problems recently in my experience.

    4. Different brands of springs yield slightly different fps ratings, I'd say if you have a chrono available, then short stroke one at a time until you get desired velocity. Probably either 1 or 2 teeth. Each tooth short strokes will take off 10-15 fps and will help reduce chances of PME.

    5. Not sure about the TVS diode, but I've heard nuke fets to be good, if not, zardichar sells them pretty cheap and they work well.

    6. I've heard that same thing about dsg's. I talked to zardichar about that same question recently and I was told that both would yield a very similar rof, but 10:1's with 22 tpa would be slightly more efficient.

    6.5. Both setups you listed would give higher rof than you listed. On an 11.1, both would probably yield in the lower 60's rof wise.
     
    Last edited: Jul 10, 2014

  3. natethegreat

    natethegreat New Member

    782
    0
    Brighton
    Ok thanks, il go one at a time here, with my piston i am very aware of the weight, so i swiss cheesed as much as i could and i have a friends shs to compare, and it is lighter on the scale, the higher rps is not a big deal to me, as for the short stroking, i dont have a chrono available, but my field has one, as soon as its together i will test, and then adjust from there, thanks for all the help :)




    Build the best dont buy the best
     
  4. Lefse

    Lefse Well-Known Member Supporting Member

    4,723
    119
    The weight isn't the only disadvantage of the Lonex piston, the SHS piston will simply last much much longer. I have stripped several Lonex piston, I have yet to break a single SHS piston. I've had them survive catastrophic PME without a scratch, the sector gear cracked instead. For me there are no reasons to use a more expensive and less durable Lonex piston, the only reason might be if you want a mechanical "fuse". That doesn't make sense though, as you can get a new gear cheaper than a Lonex piston.
     
  5. natethegreat

    natethegreat New Member

    782
    0
    Brighton

    I guess now this is down to personal preference. It came in my gun, and it has zero wear, im not arguing, because i do know the shs piston is wonderful, and better. Its my piston of choice for my dsg.


    Build the best dont buy the best
     
  6. Main_Stream

    Main_Stream New Member

    439
    1
    Troutville
    Okay my responses are in bold. Your build goal is very reasonable here!
     
  7. natethegreat

    natethegreat New Member

    782
    0
    Brighton
    Ow wow thank you, all of your points really make sense to me, i just have a few curve balls, the lonex cylinder i have is not a type O, or type 1, im not sure what to call it, ImageUploadedByAirsoft Society1405041211.628921.jpg i have a feeling that i may be a tad over volumed here running a 363 barrel. I also allready bought the a1, so sadly im stuck with it, with all of my future parts i really have to keep it under 90$, also i have a new problem, ImageUploadedByAirsoft Society1405041464.295516.jpg So that distance is the measurement with my grip on when im testing without my body, and when i put my body on, i lose that much space, its hard to describe, but when i adjust my motor height with half shell, its good, then i put it in my outer body and its off. So, should i dremel my grip or compensate for the distance in half shell?


    Build the best dont buy the best
     
  8. Main_Stream

    Main_Stream New Member

    439
    1
    Troutville
    I'll help with the over voluming. If you are over volumed try adding more weight to your piston and piston head by buying ones with ball bearings. However in your case I would highly suggest you get a Type 2 Cylinder, as your Type (unknown) cylinder is providing too much air.
     
  9. nathan327

    nathan327 Active Member

    1,043
    9
    Near Columbus
    This is a high speed build, so you don't want to add too much weight to the piston. A ball bearing wouldn't hurt anything, but in this case it's much more effective and efficient to just get a proper volumed cylinder. I'd only suggest that you compensate for slight over voluming by weighting the piston if you plan on shooting .40+ gram bbs on a pretty low speed setup.
    Otherwise, it is better to use a proper volumed cylinder.
     
  10. Main_Stream

    Main_Stream New Member

    439
    1
    Troutville
    Wow... I forgot it was a high speed setup. :eek:

    Yeah, don't make your piston heavier. Go ahead and Swiss Cheese it. Also, get a Type 2 cylinder. That should be the correct size for your gun.

    Also, It's okay that you got the A1, just make sure that you don't put in a super strong spring that it can't pull. The A1 is balanced so I'd guess it could take up to an M150.
     
  11. nathan327

    nathan327 Active Member

    1,043
    9
    Near Columbus
    I wouldn't take it that high, I'd say, as the OP stated, an m130 would be good. I wouldn't go past an m140. Not exactly sure how strong it is (18 tpa? And not the strongest magnets in my experience) but that paired with 12:1's could get ugly if you try to pull too much. It could just be that I'm not a huge fan of Lonex motors though...

    Also, OP, I didn't see a spring guide in that build list. Either you already have a Ball Bearing one, or you forgot about it. If you get a ball bearing spring guide, not only is it more durable and adds a little boost to your fps, but you can take the ball bearings out of your piston head, since they are only needed on one side of the spring. This will deduct a little more weight off of your piston assembly as well.
     
  12. averageairsofter

    averageairsofter New Member

    1,052
    0
    Menifee
    This build looks pretty nice and similar to what I am doing to my fmg4 but as nathan said replace the stock spring guide, it is plastic and not bearing which is no good, I replaced mine with a g&g metal bearing spring guide I had lying around but any metal bearing spring guide will do.
     
  13. BoogerMc

    BoogerMc Airsoft Jedi Master Supporting Member

    4,555
    4
    Akron
    Since no one has answered the question about the TVS diode, I will.

    As I have recently gotten into building MOSFETs, but have some electronics knowledge, a TVS diode acts as a surge protector for the MOSFET chip. It allows excess current to go around the MOSFET so as not to damage it. Here is an article that explains it nicely and shows how to make your own MOSFET.

    http://unconventional-airsoft.com/2009/08/26/how-to-make-a-basic-mosfet-switch/

    I have used this design and it works, admittedly, I did not have a TVS diode at the time, so I left it out, but otherwise, this MOSFET does work. I made a few modifications to prevent frying the MOSFET, such as using a screw terminal to allow me to add the MOSFET after the circuit was completely constructed, and I increased the heat sink to allow for more cooling to reduce the chance of overheating the MOSFET.

    Here is a picture of another MOSFET that I added these mods to, you can see the terminal strip (black block) and the additional heat sinks (copper tabs).

    [​IMG]

    That little black cylinder in the picture is the TVS diode, by the way.

    Anyway, hope this helps.
     
    Last edited: Jul 11, 2014
  14. natethegreat

    natethegreat New Member

    782
    0
    Brighton

    The stock spring guide is crap, simply crap. Same here, i replaced mine with the g&g spring guide.



    Build the best dont buy the best
     
  15. natethegreat

    natethegreat New Member

    782
    0
    Brighton

    I guess i put one in there, im going to get the zci steel bb spring guide. Yeah i kind or "regret" buying the lonex, its just not good quality. It is actually 16 tpa. And i think people have pulled m200's. So im in the clear.



    Build the best dont buy the best
     
  16. Main_Stream

    Main_Stream New Member

    439
    1
    Troutville
    Don't regret buying the Lonex. :p

    i personally like Lonex's. Everyone has an opinion. Why don't you like them?
     
  17. natethegreat

    natethegreat New Member

    782
    0
    Brighton
    So i think i get it, the tvs diode will only let as much power in as it needs? And its not any sort of fuse? Should i install a fuse? I have heard of 50 amp fuses being sufficient. But im not sure how to tell what i would need, my battery is a gens ace 4000mah 25c 11.1. So that would be a 100amp battery? Im good with mechanical, but when somebody says electric, i have no clue.


    Build the best dont buy the best
     
  18. nathan327

    nathan327 Active Member

    1,043
    9
    Near Columbus
    I'm not that great with electrical stuff either, but I run a 30 amp fuse on my builds and it works fine. My 11.1v 40c 4000mah battery will blow 20 amps quickly, just burn the filament of a 25 amp, and works just fine on a 30. 50 amp seems a little high to me, don't quote me on it though. But yes, it would be a great idea to install a fuse.
     
  19. natethegreat

    natethegreat New Member

    782
    0
    Brighton

    Ok thanks, so should i just solder right to the fuse or find some sort of holder?
     
    Last edited: Jul 11, 2014
  20. nathan327

    nathan327 Active Member

    1,043
    9
    Near Columbus
    Get some sort of fuse holder where you can change the fuse. If you solder directly to the fuse, then you'll have do de solder and resolder every time you blow a fuse. Or you could get a self resetting poly-fuse that once it blows, it will reset it's self and work again when the battery is unplugged. Either way, I would still recommend you get a fuse holder instead of soldering a fuse directly to your wires.