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First Time High Speed Build Questions!?


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Old 06-30-2017, 01:12 AM   #1
Trapfix
 
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Default COMPLETED CHECK IT OUT: First Time High Speed Build Questions!?

Before I begin, let me just say that I am not asking to be spoon-fed. I have done tons of research, have a comprehensive build list, & have done tons of work inside multiple guns, including rebuilding, fine tuning & reselling some guns I work on. However, this is the first time I'm dumping a decent amount of change into a build and I have a few Battery/SS & AB Questions.

No need to mention DIY Mods: Bearings are epoxied, as will be the piston rack, I have neoprene (Not Sorbo) for AOE etc. etc. We should all know these things bare minimum if we're building for HS

GOAL: 380~400FPS, 25-30RPS(2S)/30-40RPS(3S)

First, My Build List:
-G&P Magpul MOE (Wanted this gun/receiver set way back when I was young and couldn't afford one. Found one on craigslist & got it for a steal!)
-Stock G&P Cylinder, Cylinder Head & Air Nozzel, as well as the stock 8mm Bearings
-JG Newest Type PolyCarb Piston w/ Piston Head (Piston head is Nylon I believe, Trying to keep assembly as light as possible) [I did buy the pre-lightened SHS 15T, the one UA uses, Just in case]
-Guarder SP110 [M120 Equivalent] (Underrated for this setup? I'll find out through trial & Error)
-Super Shooter Spring Guide
-SHS ARL
-SHS HT
-SHS 13.65:1 Gearset w/ SHS Sector Delay
-SHS Tappet (Will be trimmed/Modified)
-GATE Titan Mosfet (Love trigger tuning)
-RA CNC Type B Trigger

Questions:
-At the moment, I have a 2S 20~30C 5amp Battery. Will this starve my setup, or will I be okay until I have a 3S?
-I just recently read that using a 3S battery on setups running below 380FPS could lead to PME/Overspin, Will I have to worry about this even though I have a Titan w/ AB? To clear up any confusion, I am looking at a 3S 65C 5 amp battery. I may be looking to build a DSG once I feel I've mastered the HS SSG Build & I know that battery will have the juice a DSG needs, but I'm not sure if that type of power is going to shred my HS SSG Build. I've read that your setup will only draw what it needs, but I just want to reassure myself that the aforementioned 3S isn't going to have me throwing everything I've invested in the GB straight into the trash.
-Should I SS 2 teeth off the sector before even testing this build? Especially once I have a 3S? Just to be cautious. I want this build to run so that I'm not burning through motors. AB is nice, but I don't want it to be the reason my setup works & lead to me swapping motors twice every season. Essentially, If I swapped the titan out for a regular old 3034 mosfet, I want my build to still function as well (safely) as it did with the Titan.
-Should I have gone with the SP120? SS & the heavier spring will Help avoid overspin/PME, and the heavier spring will ensure I stay in the FPS range I'm looking for.

I may have some other weird questions, but I'd just like to know what advice others who are far more experienced (I've only been doing tech work for a month or so) have to give in reference to my build. Thank you in advance for all of your help!

EDIT:
Stock 300mm Brass Inner Barrel - Will swap for a PDI 6.05 300mm IB, but not anytime soon.
-Should I be running a Type 3/4 Cylinder to properly volume, or can I get away with the stock G&P full cylinder? Regardless, I probably won't replace them for a bit.




Last edited by Trapfix; 07-07-2017 at 11:48 PM.
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Old 06-30-2017, 04:12 AM   #2
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Quote:
Originally Posted by Trapfix View Post
-Guarder SP110 [M120 Equivalent] (Underrated for this setup? I'll find out through trial & Error)
Nope, that should be fine for your 3s lipo on a 2t ss. You could probably run full-stroke but I know for certain that that spring will be perfect for 40rps on a 2t ss.

Quote:
Originally Posted by Trapfix View Post
Questions:
-At the moment, I have a 2S 20~30C 5amp Battery. Will this starve my setup, or will I be okay until I have a 3S?
-I just recently read that using a 3S battery on setups running below 380FPS could lead to PME/Overspin, Will I have to worry about this even though I have a Titan w/ AB? To clear up any confusion, I am looking at a 3S 65C 5 amp battery. I may be looking to build a DSG once I feel I've mastered the HS SSG Build & I know that battery will have the juice a DSG needs, but I'm not sure if that type of power is going to shred my HS SSG Build. I've read that your setup will only draw what it needs, but I just want to reassure myself that the aforementioned 3S isn't going to have me throwing everything I've invested in the GB straight into the trash.
-Should I SS 2 teeth off the sector before even testing this build? Especially once I have a 3S? Just to be cautious. I want this build to run so that I'm not burning through motors. AB is nice, but I don't want it to be the reason my setup works & lead to me swapping motors twice every season. Essentially, If I swapped the titan out for a regular old 3034 mosfet, I want my build to still function as well (safely) as it did with the Titan.
-Should I have gone with the SP120? SS & the heavier spring will Help avoid overspin/PME, and the heavier spring will ensure I stay in the FPS range I'm looking for.

I may have some other weird questions, but I'd just like to know what advice others who are far more experienced (I've only been doing tech work for a month or so) have to give in reference to my build. Thank you in advance for all of your help!

EDIT:
Stock 300mm Brass Inner Barrel - Will swap for a PDI 6.05 300mm IB, but not anytime soon.
-Should I be running a Type 3/4 Cylinder to properly volume, or can I get away with the stock G&P full cylinder? Regardless, I probably won't replace them for a bit.
- No, your setup will not "starve".
- PME and Overspin are not determined by FPS but rather the springs ability to return the piston to the forward position quicker than the motor can turn the gears without a load for PME. I'll skip overspin since your MOSFET has AB, but you probably won't even need AB since you've got an SP110. Back to PME, you're going to want to try out that SHS piston or swiss-cheese your JG piston, just know that SHS pistons are known for binding up. You're also going to want to remove the bearings from your piston head if you haven't already. Your spring is strong enough that you shouldn't run into PME.
- You should definitely look at SSing. Mid-30s would call for 1t ssd or high 30s to low 40s would call for 2t ssd for absolute assurance that you aren't going to perform an unintentional piston lightening job by removing your piston's teeth when you pull the triggers. I am kinda talking out my arse here though so I'm paging Hangtight who has a lot more experience than me to talk about SSing in particular.
- Getting a higher spring and SSing is always a great idea as long as your setup can handle it.

You'll want to do your own porting job on your cylinder for the specific BB weight you settle on. Once again, hangtight will have better info than me.



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Old 06-30-2017, 06:46 AM   #3
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Did I hear my name mentioned?

That is a solid, balanced and sensible build list, with the only question mark hanging over the JG piston as a bit of an unknown quantity to me.
I have just built almost this exact setup, but using an ICS POM piston and head. On 7.4v you should get around 24rps,maybe 25 if your shimming is good. Remember with bearings that you have to shim for end float rather than whether it just spins freely or not.

It should pull around 25A when running, but with a start up peak perhaps 3 times that, so my minimum suggested battery would be perhaps a 30C/50C continuous /burst, 1500mah battery.

At 25rps on an M120 spring you'll be safe from PME, so you can leave the bearing in the piston, and the remainder of the components stock other than any tricks you want to apply to improve performance. Also, this set up on 7.4 will have virtually no overspin, so leave the AB on the Titan turned off. It will also respond very well to pre cocking. Remember not to engage pre cocking in full auto. That way you can release tension on the spring at the end of the day by firing a quick burst of full auto.

On 11.1v you could expect around 35+ rps. This is heading towards the point of PME. You can loose another 3 grams off the piston by removing the bearing and replacing it with a light plastic space to maintain the spring compression. Also ensuring the cylinder is correctly volumed can help increase the piston acceleration a fraction.
I know that when I ran a very similar setup with a stock weight piston it hit PME, so there's not much margin. If you tend to a more cautious approach then consider going to an M130 spring and short stroking to bring the fps back down. With a 300mm barrel you've got the spare volume to do it without losing any efficiency.
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Old 06-30-2017, 07:12 AM   #4
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Quote:
Originally Posted by Trapfix View Post
Bearings are epoxied,

....as well as the stock 8mm Bearings
Bushings not bearings on high rate builds - at least a solid bushing under the spur as this fails the most
Or you will be rebuilding the box at around 20k

To each their own but think you would want mostly bushings
Bushings x 2 on bevel
Bushing under spur - maybe bearing on top but has to be bushing underneath
Bushings on sector - it rotates the least of all gears so make it durable

I had a stock 7mm bearing setup fail very very quickly due the bearings wrecking within 13k. 8mm are stronger but I still wouldn't risk it after having to rebuild & reshim so quickly because the stock 7mm bearings wrecked, enormous wear created excessive play, lost bevel & new pinion req
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Old 06-30-2017, 09:14 AM   #5
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The stock G&P bearings are amongst the toughest out there, and properly set up on an M120 build they'll run and run, but it's always worth keeping an eye on them just in case.
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Old 06-30-2017, 09:43 AM   #6
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Quote:
Originally Posted by Sitting_Duck View Post
Bushings not bearings on high rate builds - at least a solid bushing under the spur as this fails the most
Or you will be rebuilding the box at around 20k

To each their own but think you would want mostly bushings
Bushings x 2 on bevel
Bushing under spur - maybe bearing on top but has to be bushing underneath
Bushings on sector - it rotates the least of all gears so make it durable

I had a stock 7mm bearing setup fail very very quickly due the bearings wrecking within 13k. 8mm are stronger but I still wouldn't risk it after having to rebuild & reshim so quickly because the stock 7mm bearings wrecked, enormous wear created excessive play, lost bevel & new pinion req
OP should be fine with his bearings, G&P bearings are very durable. I haven't had a single G&P bearing fail and I've used them in setups far more stressful than this one. My oldest set passed is probably close to 200 000 shots by now and seem to be running fine still. I shim my gears very carefully so the bearings don't have more sideways load than necessary.

7mm bearings are a different story, they work for low stress setup, but are to fragile for any serious setup.

OP, your setup looks pretty solid to me, it should run well, and your battery is plenty strong enough.
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Old 06-30-2017, 12:25 PM   #7
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Fair enough - but like I said I'd fit a bushing under the spur....


I still stand by what I said:

Quote:
8mm are stronger but I still wouldn't risk it after having to rebuild & reshim so quickly because the stock 7mm bearings wrecked, enormous wear created excessive play, lost bevel & new pinion req
but as I also said:

Quote:
To each their own.....
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Old 06-30-2017, 01:38 PM   #8
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I was initially sceptical about using bearings over bushes, but I got a G&P gearbox that was already fitted with them so they are what got used because I didn't have any bushes to hand. Then you start to read of people having bad experiences with bearings collapsing, but so far the G&P ones have been fine.

Of the failed bearings that I have seen, they seem to be of the low friction kind. Usually very hard with fewer ball bearings and not really suited to high acceleration or shock loads. At some point I'll pull a G&P one apart but I suspect I'll find a high bearing count. Just because bearings are more expensive doesn't mean they are better for a particular task. Roller bearings would be ideal for the spur gear and sector, and under the bevel, with a taper roller on top to take the axial load.... Or just stick bushes in there!
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Old 06-30-2017, 04:12 PM   #9
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Quote:
Originally Posted by Hangtight View Post
Did I hear my name mentioned?

That is a solid, balanced and sensible build list, with the only question mark hanging over the JG piston as a bit of an unknown quantity to me.
I have just built almost this exact setup, but using an ICS POM piston and head. On 7.4v you should get around 24rps,maybe 25 if your shimming is good. Remember with bearings that you have to shim for end float rather than whether it just spins freely or not.

It should pull around 25A when running, but with a start up peak perhaps 3 times that, so my minimum suggested battery would be perhaps a 30C/50C continuous /burst, 1500mah battery.

At 25rps on an M120 spring you'll be safe from PME, so you can leave the bearing in the piston, and the remainder of the components stock other than any tricks you want to apply to improve performance. Also, this set up on 7.4 will have virtually no overspin, so leave the AB on the Titan turned off. It will also respond very well to pre cocking. Remember not to engage pre cocking in full auto. That way you can release tension on the spring at the end of the day by firing a quick burst of full auto.

On 11.1v you could expect around 35+ rps. This is heading towards the point of PME. You can loose another 3 grams off the piston by removing the bearing and replacing it with a light plastic space to maintain the spring compression. Also ensuring the cylinder is correctly volumed can help increase the piston acceleration a fraction.
I know that when I ran a very similar setup with a stock weight piston it hit PME, so there's not much margin. If you tend to a more cautious approach then consider going to an M130 spring and short stroking to bring the fps back down. With a 300mm barrel you've got the spare volume to do it without losing any efficiency.
I'll just go ahead and mention these so people don't waste their time talking about them: Piston is going to be swiss cheesed to heck and back with a window in the top, Bearings in the piston head will indefinitely be removed, GB is already radiused, Bearings are epoxied, Piston rack will be epoxied, the type B trigger will be modified to fit so it doesn't interfere with the gate & the piston will also be checked for resistance within the GB & modified as needed. Neoprene will be scorn & secured with epoxy & then sanded into a cone/funnel shape to maximize air being pushed through the cylinder head. Phew. Okay, moving on.

I'm glad you actually mentioned shimming with Bearing because I haven't really found anything on the difference aside from one source saying leave .04mm room with Bushings & .08mm with Bearings. I typically shim so that I visibly can't see the side to side play in the gears, but I can feel it & they spin freely without any friction bringing them to an abrupt stop. Is this correct? I also try to leave a very small amount of room between the gears, probably about .02mm at most. Is this correct as well? Or is this beyond the 50-90% range people shoot for?

Going back to my battery, it's a 2S 20C~30C 5 amp battery. (20C)x(5Ah)=100 Amps constant discharge? Or something like that, not sure the exact terminology for the answer to said equation, but given that you're saying my draw will be around 25A & about 75A to get it going, I shouldn't have to worry about dipping the voltage of my Lipo, right? Essentially, my battery is sufficient for a field day of 5-6 hours with breaks in between games.

Honestly, I didn't do too much research on the Titan before buying it, other than seeing the install and knowing the bare-bones functionality of it. I more or less bought it because I figured I'd never find a Spectre, I like the trigger tuning/optical sensors more & It was in stock for the first time since I've been airsofting, so I wanted to hop on it while I could. I'll tinker with it/read up on it before it arrives so I'm ready to drop it in & get my setup up & running.

Guarder SP110s can shoot a little hot, even after broken in. I went with this spring because I already bought one and threw it in a different build & like the performance I was getting. I'm probably going to play to my own skepticism & SS 2 teeth off the sector (1) because I can pop in the 3S battery when I get it & (2) because If I am shooting hot, say 405-410 (compression in my gun is incredibe- hop up is shimmed to GB too) then SS 2 teeth will take me down to 385-390 at the fire rate I'm looking for. It is about 10FPS per tooth, correct?

I'm going to stick to the G&P bearings. For every one person that sees them fail, hundreds/thousands of others don't complain because they succeed. The issue isn't isolated to the bearings themselves. They could be failing simply because of gear axle alignment or a hundred other things unknown to anyone aside from the tech complaining about how they failed.

Lastly, thank you for giving me another way of looking at the ported cylinders! I do realize how voluming works, but I hadn't yet thought of it in terms of friction. If Friction/minute discrepancies in piston weight didn't matter, we wouldn't be doing seemingly pointless mods such as swiss cheesing pistons & reducing friction as much as possible. To those who say SC a piston doesn't do anything, show me one RELIABLE DSG build with a standard weight piston. Thank you for the insight!

I'll keep everyone posted on how it turns out, just waiting for parts to arrive this coming week!
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Old 06-30-2017, 04:18 PM   #10
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Ohhhhh one more thing! Should I buy an STS? I only saw one video about one & Legacy's HS guide recommends/mentions them, but out of all the high speed builds I've seen in person & on YouTube/Forums, no one really mentions them & I don't see them. Was it a hype thing a while ago, something that's just accepted & not mentioned, or what?



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