air compression - realisticly what will i be losing out on?

[joshh1512]

Hi guys, just picked up a dboys pdw on the forums and had nothing but trouble with it since i got it.. anyway to say the least its shooting 160fps with the hop off (also a question about this later) and i've replaced the spring with a couple others in my spares box and its still low.

So ive stripped it down again and done a compression test, it's pants. put my finger over the nozzle and piston slides in reasonably easy with only a little force pushing against it. I think its possibly a g&p piston/head set its all black anyway, couldnt get a spare piston head i had to fit on it which was a dboys... the cylinder again looks g&p (i think but not sure its silver with lines accross it) and the cylinder head is stock dboys with some teflon tape around it.

So yeh my question is, could this kind of compression really be making me lose so much fps i.e. 200, or is there a problem elsewhere? I've also tried 3 different hop chamber sets in it and still the same result.

Before i go ahead an purchase some new parts just wanting your views on whether this actually is the issue or not.

Cheers... and out of interest heres the proposed list of bits i'll get for it, any views?

lonex double o-ring cylinder head
Ultimate asg polymer air nozzle with internal o ring
lonex pom piston head

i was gonna get the lonex air nozzle, however that is for m4 and m16 series, i read that the m16 series uses a slightly different length to the m4 series in other brands, this true?
And can i stick with the original piston so long as i get the new head on it? already shaved down thats all would save me a shaving new one..

Then also sticking in shs 18:1 gears and then for the motor need your ideas - £45 Lonex A2 torque or £28 GFC tornado F1 torque motor? Obv rather the later, how do they compare to the shs ultra high torque as i previously had this and it was amazing, are both neo magnet motors?

cheers guys.

[Mickydoos]

Re: air compression - realisticly what will i be losing out on?

You're right about the compression. It could easily lose you 150-200fps. Air nozzle wise yours is probably fine but I would compare the two at strip down and if the replacement is too long take a file to it.

I personally would also go Lonex/SHS piston.

The A2 is superior to the SHS Hi-torque as its runs cooler, has slightly better speed and efficiency BUT the SHS is by no means a poor motor. I use one in my G&G GR15 and it made it beastly compared to a stock motor. Sorry, but i have no experience with the GFC.

[joshh1512]

Re: air compression - realisticly what will i be losing out on?

Glad to hear that mate just ordered a boat load of parts...

Gone full lonex route for the cylinder, all the stuff that was in there simply looked old and worn down,

Lonex 110-300mm barrel cylinder, aluminium double o ring cylinder head, POM piston head and then the blue lonex piston and finally then polymer lonex nozzle.
Also a new lonex m100 spring as didn't have a clue what power the ones in my spare box were lol.
Also ordered the lonex A2 high torque motor, SHS 16:1 speed gear set which i've had good experience with before, and some cheapos in the sale a new element tappet plate, selector plate and AR latch, totally un-required but they were in the sale and couldn't help my self haha. Got a bearing spring guide too rather than the standard metal one it currently has.

Any tips on getting a perfect airseal for the cylinder? I'm hoping it should already be helped sticking with the same branded parts for cylinder area..

Also a question on AOE correction, firstly should i take of the rubber pad which comes with the cylinder head, or can i just roughen this up and stick new pads to it? next.. do i have to use sorbo pads, or will rubber washers do? just i only have 3 of the thin sorbo pads left from a set, but i would have the rubber pad which comes on the cylinder head, and then also another rubber pad taken off an old cylinder head - i could glue this to the stock one, and then add sorbo pads on top of this if required?

Finally the other question was to do with the hop, with the hop fully off i should see no pressure of the bucking down the barrel right? not the case for me - with the hop off i can see the nub poking down a little bit, any ideas what could be the cause? i glued the nub to the arm if thats helps decipher the problem as it was a nightmare, kept falling out.

thanks alot for the reply! shall update you guys how the build goes, hopefully get it done for sunday .

[Mickydoos]

Re: air compression - realisticly what will i be losing out on?

Any tips on getting a perfect airseal for the cylinder? I'm hoping it should already be helped sticking with the same branded parts for cylinder area..

Use silicone grease on the cylinder head to help with the seal. Failing that, use some PTFE tape (teflon) to make it tighter.

Also a question on AOE correction, firstly should i take of the rubber pad which comes with the cylinder head, or can i just roughen this up and stick new pads to it? next.. do i have to use sorbo pads, or will rubber washers do? just i only have 3 of the thin sorbo pads left from a set, but i would have the rubber pad which comes on the cylinder head, and then also another rubber pad taken off an old cylinder head - i could glue this to the stock one, and then add sorbo pads on top of this if required?

Personally I left it one but used sorbo on top. It depends on how much it messes up your AOE. If you have to remove more than 2 teeth from the piston consider cutting down the rubber/sorbo rather than remove a third or fourth tooth off the piston.

Finally the other question was to do with the hop, with the hop fully off i should see no pressure of the bucking down the barrel right? not the case for me - with the hop off i can see the nub poking down a little bit, any ideas what could be the cause? i glued the nub to the arm if thats helps decipher the problem as it was a nightmare, kept falling out.

You'll normally see a little bit. Chances are the glue is acting a bit like a spacer of sorts. I've heard of people sanding downt he arm prior to gluing the nub down. I've never botherd gluing it it, I don''t have that problem myself lol

[Lee 303]

Re: air compression - realisticly what will i be losing out on?

First thing I would have done was replace the piston O-ring and then done a compression test