Losing FPS in changing hop-up

[Shirley]

Have you guys ever lost any FPS from changing a hop up from 2 piece to a 1 piece?

After changing to the metal body, and then getting the 1 piece lost FPS about 20 FPS or so.

Cleaned the barrel, added silicone oil into the hop up too.
Cleaned the barrel until the papers were white.


I've also sealed up the hop up, the clip part with electric tap, and where the o-ring is. I am sure there no air there can be lost.

My JG was shooting 380 FPS last time I gamed with it on a plastic body with 2 piece hop up.


Now it's probably around 350 and cannot pierce the bottom of the can using .2g.

Is that supposed to happen? Losing FPS when changing hop up?

[ujiro]

changed the hop up rubber at all? or just the hop up.

[Shirley]

Originally Posted by ujiro

changed the hop up rubber at all? or just the hop up.

The whole piece, and also used the new rubber too.

When was the last time you gamed it? JG springs are know to settle down a fair bit after a few bags of ammo.

[Shirley]

I gamed it on Aug 4th.
Hmm, I probably think it is the spring.

I probably ran 3000 rounds. Max.

[Styrak]

Originally Posted by Mr.Hitman

The whole piece, and also used the new rubber too.

Changing the rubber could do it. Who knows what differences there are in the 2 rubbers, not to mention the nubs.

Also you sure the hop was completely off both times

[Shirley]

Originally Posted by Styrak

Changing the rubber could do it. Who knows what differences there are in the 2 rubbers, not to mention the nubs.

What are the nubs?

Originally Posted by pawscal

Also you sure the hop was completely off both times

Yes it was.

[ancorp]

The nub is the little rubber piece that presses onto the rubber.

Another reason might be not as great of an airseal on this hopup unit itself.

[Shirley]

Originally Posted by ancorp

The nub is the little rubber piece that presses onto the rubber.

Another reason might be not as great of an airseal on this hopup unit itself.

Probably.

I changed the rubber back to the original one on the other, and same. Maybe just the airseal. Bleh.

[jesster202]

drop the jg spring and go pdi i know its funny but if you want not mess around in the mech. to try to get back your 10/20 fps go tight bore and ka enhaced hop up

[Amos]

If you've got a Dboys metal body it's most likely a fitment with the hopup chamber

[Shirley]

Originally Posted by jesster202

drop the jg spring and go pdi i know its funny but if you want not mess around in the mech. to try to get back your 10/20 fps go tight bore and ka enhaced hop up

Hmm, I do have a AK tightbore barrel. Not sure if I want to change my hopup just for a few more FPS. I'd rather change the spring than the hop up though. But I hate getting into the gearbox. It's a mess for me, I'll rape it. And get a headache after like last time. I plan to open the gearbox again when these plastic bushings are worned out. Then I can add in a new spring and metal bushings.

It was running pretty well under the 400's.
Guess I'm back with the crowd with 330-350 FPS AEGs.

Originally Posted by Amos

If you've got a Dboys metal body it's most likely a fitment with the hopup chamber

I do have the Dboys body, and it fits right well in there. Probably just the hop up itself, or the spring. Only way to check is if I put it back to my plastic TM body and test it out with the 2 piece again which is a hard lot of work.
I decide to keep it the way it is, till something goes worst, than I'll switch to quality parts.

[m102404]

Aside from the good advice already here (hopup rubber/nub, etc...)...

Try easing off your stock screw a bit...not to make it loose, but rather just finger tight.

There's a lot of play in some Dboys bodies and if you have the rear screw really tight it'll pull the mechbox away from the hopup. The spring on the hopup is supposed to compensate by pushing the hopup unit tight against the mechbox and thus ensuring that the nozzle is making a good seal with the rubber...but to do that it has to spring freely (not sure if it is if you put electrical tape around the clip) and actually push against the mechbox...not bounce against it.

You're looking at minute movement here...but enough to create air loss under pressure.

Best of luck,

Tys

[Shirley]

Originally Posted by m102404

Aside from the good advice already here (hopup rubber/nub, etc...)...

Try easing off your stock screw a bit...not to make it loose, but rather just finger tight.

There's a lot of play in some Dboys bodies and if you have the rear screw really tight it'll pull the mechbox away from the hopup. The spring on the hopup is supposed to compensate by pushing the hopup unit tight against the mechbox and thus ensuring that the nozzle is making a good seal with the rubber...but to do that it has to spring freely (not sure if it is if you put electrical tape around the clip) and actually push against the mechbox...not bounce against it.

You're looking at minute movement here...but enough to create air loss under pressure.

Best of luck,

Tys

Thanks, I did actually try that before and after, no changes. I guess it's just the hop up. Probably move onto buy a quality one next time. Tried so save a few bucks and bleh. Back to plan 1.