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Old 06-24-2014, 02:20 AM #1
Razgriz2006
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FEP Quest mod proposal

Mods to be attempted
1. Bolt arm trimming from 10 to 3 (.1211 cubic inch volume increase or operating pressure reduction of 14.5 %) 220 > 188.1
2. Forward stroke bumpering (014 oring on the bolt tip) remove material from the front of the bolt sail to ensure forward bolt movement is kept the same
3. Rear bolt bumpering (Juit already did this) 50 durometer 111 instead of plastic washer


I will remove .006 inches of metal behind the green oring to make the bolt timing be unaffected



this is how much room the dump chamber has to vent through during firing. removing 7 of the 10 bolt arms will make this transition flow much better.

I am worried that the reduced bolt arms could reduce the structural integrity of the bolt. However the bumpering and lower LPR seetings achieved from better/softer orings and lurker lube should greatly decrease the forces exerted on the bolt.

Any thoughts are are appreciated!

Bolt travel length .88 inches

Bolt tip length 1.019
Dump chamber begins dumping at .75 inches bolt travel
Not coincidentally the SFT oring is .75 inch bolt travel

Guide pin rod .156 inches diameter
Guide pin rod length 1.486 inches
Π x .078^2 x 1.486= .028 cubic inches of volume taken up by guide rod pin
Bolt Interior diameter = .685
Π x .3425^2 x 1.486 = .55 cubic inches of air
.55- .028 = .522 cubic inches of guide rod dump chamber volume

.788 outer bolt dump chamber diameter
2.094 outer bolt dump chamber length
.084 marker body interior diameter

Π x .42^2 x 2.094 = 1.16 Cubic inches
Π x .394^2 x 2.094 = 1.02 Cubic inches
Bolt cuts length (straight) =1.275
Bolt cuts width= .125
Bolt cuts circle R=.067 thickness is .103 (.0014) +.015937

Each Bolt cut yields .0173 cubic inches of volume or .173 cubic inches in total

1.16-1.02 + .173+.522 = .835 cubic inches of dump chamber volume
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Old 06-24-2014, 07:05 AM #2
ironyusa
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Ryan and I talked some time ago about adding an oring gland to the front of the bolt, where that HNBR bumper is and drilling a few holes through the bolt to assist in ythe closing speed. If you did that, you could potentially drill a purge hole ~.7mm through the bolt pin and allow the firing chamber to keep charging. That should lower the operating pressure and boost efficiency. Adding a QEV or something like the shocker eigen is possible as well if you machine a gland on the ID of the bolt at the back.
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Old 06-24-2014, 10:09 AM #3
Razgriz2006
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Quote:
Originally Posted by ironyusa View Post
Ryan and I talked some time ago about adding an oring gland to the front of the bolt, where that HNBR bumper is How hard is that to do and make it look professional?

and drilling a few holes through the bolt to assist in ythe closing speed.Could you explain this more?

If you did that, you could potentially drill a purge hole ~.7mm through the bolt pin and allow the firing chamber to keep charging. Wouldnt that make the gun sensitive to high (cheating) dwell values?

That should lower the operating pressure and boost efficiency. Adding a QEV or something like the shocker eigen is possible as well if you machine a gland on the ID of the bolt at the back.
I personally dont have any machines to play with other than a dremel So I think the QEV is out.

Lol also right now I am currently unemployed (PLEASE OH PLEASE SOMEONE GIVE ME A JOB!!!!!!) so sending the bolt to a professional is not in the cards at this time. The purge hole intrigues me but I wonder if there are other methods to decreasing a Quest's operating pressure. I thought of boring out the body sleeve of the dump chamber but that would require studying the bolt to understand what part of the body is never touched by an oring.

appreciate the input.
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Old 06-24-2014, 10:38 AM #4
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On the OD, since it will be a non-critical seal (in the bolt's forward position, it should ~seal at the rear lip of the feedneck) shouldn't be too difficult. If you have a steady hand and a way to chuck-up the bolt, then you can use a sawzall blade or even a cut-off wheel to cut the gland. Then just clean it up with a fine file and drill one or two tiny holes between that forward bumper and the new oring. Depending on how deep the gland is cut, you can go with massive stretch or a metric oring there. I have chucked stuff like this up with a dowel (or drill bit) taped to the part. On my quest, I also put the bumper on the rear sail area just in front of that back oring and it worked perfectly.

Pretty much all spools are dwell sensitive. The shut-off is a stop-loss for efficiency and not much more. That said, the valve dynamic can be improved by improving the switch resolution. The QEV trick Ryan figured out specifically addresses the switch and boosts the effect on the critical dwell.

As for drilling through the pin... well, I did a similar mod on an etha pin and gained 40fps with no other changes. Like an idiot, I didn't think about the hole robbing air from the air spring and didn't get to finish testing that concept. If you get a crisp enough switch from the pressure (that appears to be a good amount of area, so it should be a dramatic closing boost) then you just need to get your dwell low enough to prevent oscillation.
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Old 06-24-2014, 06:43 PM #5
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Cutting that many tines from the bolt body will probably give you structural issues like the older GM bolts have, more so with the bumper at the front of the bolt. I believe the RSF is a better example of how to do it; less but thicker tines and larger dump channels. I'd say take 5 off at most.

If all you want is to drop the OP, you can raise the dwell to about 14ms, use an underbored barrel with a long control bore and lower the OP accordingly, the valve chamber is already much larger than it needs to be, hence the tape mod giving you better efficiency.

I'd much rather reduce the chamber size slightly more than needed, thin the bolt pin down at the chamber shutoff for constant air feed, and bore the body at an angle, bevel the inner edge of that channel and plug it with a set screw, to where I get oblong bleed ports at the part where the rear outer chamber o-ring sits when the bolt is in the forward position, that way HP air bleeds into the front LP area, helping re-set the bolt like the shocker eigenbolt does, one on top and another on each vertical side; I've considered doing it with #8-32 X 1/4" set screws and the appropriate bit on a drill press. (This probably only looks half decent with the OG bodies, 07's are a different story as far as looks)

I'm thinking it'd probably feel/sound like an snappier insight (because of the heavier bolt). Even then, you could probably still get away with lower LPR pressures because of how much larger the rear sail area is than the front. Plus you could run your bolts with no mods; say yours snaps, you can get a factory stock/critical/GM/4B replacement and it'd drop right in.

Still haven't run any numbers, but I think the theory is solid.

Last edited by tacxplosion : 06-24-2014 at 06:49 PM.
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Old 06-24-2014, 07:25 PM #6
Razgriz2006
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Quote:
Originally Posted by tacxplosion View Post
Cutting that many tines from the bolt body will probably give you structural issues like the older GM bolts have, more so with the bumper at the front of the bolt. I believe the RSF is a better example of how to do it; less but thicker tines and larger dump channels. I'd say take 5 off at most.

If all you want is to drop the OP, you can raise the dwell to about 14ms, use an underbored barrel with a long control bore and lower the OP accordingly, the valve chamber is already much larger than it needs to be, hence the tape mod giving you better efficiency.

I'd much rather reduce the chamber size slightly more than needed, thin the bolt pin down at the chamber shutoff for constant air feed, and bore the body at an angle, bevel the inner edge of that channel and plug it with a set screw, to where I get oblong bleed ports at the part where the rear outer chamber o-ring sits when the bolt is in the forward position, that way HP air bleeds into the front LP area, helping re-set the bolt like the shocker eigenbolt does, one on top and another on each vertical side; I've considered doing it with #8-32 X 1/4" set screws and the appropriate bit on a drill press. (This probably only looks half decent with the OG bodies, 07's are a different story as far as looks)

I'm thinking it'd probably feel/sound like an snappier insight (because of the heavier bolt). Even then, you could probably still get away with lower LPR pressures because of how much larger the rear sail area is than the front. Plus you could run your bolts with no mods; say yours snaps, you can get a factory stock/critical/GM/4B replacement and it'd drop right in.

Still haven't run any numbers, but I think the theory is solid.

I will take my reg off and pressure test it in a little bit.

I disagree with dump chamber being too big. I think 220 psi is really high and id like to get it down to about what my pm8.9 runs at. I think the reason why the tape and juit mods work is because of the chamber not dumping efficiently.

you bring up a good point about the front bumpering creating more stress... I do have two bolts and two pins so if one snaps its not the end of the world.

I think I need a graphic representation of what you are proposing with the set screws.

My current settings:
dwell 12
.680 UL and .678 eigen (pretty much the same if the eigen isint breaking)
lpr is all over the place (I took out the gauge) but I tuned it like you would a dye lpr over a virtue clock.

My initial idea was 5 arms but the only way to make it symmetrical I found was to have 3 arms
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Old 06-24-2014, 08:54 PM #7
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Quote:
Originally Posted by Razgriz2006 View Post
I will take my reg off and pressure test it in a little bit.

I disagree with dump chamber being too big. I think 220 psi is really high and id like to get it down to about what my pm8.9 runs at.
If you want a lower OP, you'll need to make the valve chamber permanently open feed, that way the chamber pressure drops less during the cycle (I believe I suggested this on your PM8 mod thread).

Also the DM9 runs a dwell of 18+ms Vs. the Quest's 8ms, this allows the valve to be open longer, which is why the quest has better efficiency than a matrix of the same time period (but a louder pop than the usual spool chuff).

Quote:
Originally Posted by Razgriz2006 View Post
I think the reason why the tape and juit mods work is because of the chamber not dumping efficiently.
The GM and 4B bolts also get better efficiency by reducing the chamber size (the 4B by enlarging the bolt pin as well as reducing the distance between chamber o'rings). The 4B bolt still has 10 tines (as far as I can tell from the drawing on ZDSPB). The RSF bolt has 4 wider tines and 4 wider air paths for the chamber to dump, but still doesn't get as good efficiency as the 4B.

It doesn't dump the whole valve chamber, not because the valve doesn't dump efficiently (It dumps more efficiently than a matrix), but because the valve closes before it empties the chamber; if you raise the dwell more, it'll dump more of the chamber.

Quote:
Originally Posted by Razgriz2006 View Post
you bring up a good point about the front bumpering creating more stress... I do have two bolts and two pins so if one snaps its not the end of the world.

I think I need a graphic representation of what you are proposing with the set screws.
I'll give it a try once I get back home, expect MS Paint though.

Quote:
Originally Posted by Razgriz2006 View Post
My current settings:
dwell 12
.680 UL and .678 eigen (pretty much the same if the eigen isint breaking)
lpr is all over the place (I took out the gauge) but I tuned it like you would a dye lpr over a virtue clock.

My initial idea was 5 arms but the only way to make it symmetrical I found was to have 3 arms

Last edited by tacxplosion : 06-25-2014 at 09:21 AM.
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Old 06-25-2014, 07:38 AM #8
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If you look where the back oring on the bolt lines up with the oring on the bolt pin, just behind the oring on the pin is where I'd put the gland on the ID of the bolt. Then I'd drill straight through the bolt so that when the hole passed over that oring on the pin it's seeing the HP air in a similar fashion to what you've suggested without ruining the body. If you were to do a bolt from scratch, you could scoot that rear switch oring on the bolt forward to make sure you had adequate room on the ID for another ring, but the concept is all the same.

Look at the top pic, for the other option of doing the oring on the very tip. The area where air flows through the bolt face is the air you'd be using. Put the oring gland on the OD of the bolt where it sealed that area between the feedneck and the forward most oring on the bolt. Then drill through the bolt. When the air is flowing through the valve it will help switch the bolt.


Once you get a cleaner switch, you can eliminate the shut off. Doing something like this should gain you efficiency AND a lower pressure. You will also run a lower dwell.
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Old 06-25-2014, 09:23 AM #9
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The port inside of the body in my suggested mod should be beveled to avoid shredding o'rings.

Irony's mod would probably close the bolt faster because it's dumping closer to the acting surface directly from the HP feed, rather than from a decreasing pressure in the valve chamber; while mine requires less tooling/machining but irreversibly changes the body's aesthetics and dumps from the valve chamber. If the shutoff is taken off, the later would almost be a moot point.

Last edited by tacxplosion : 06-25-2014 at 10:24 AM.
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Old 06-25-2014, 10:08 AM #10
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Yep, and the 3rd option that was actually Ryan's was to do the oring and hole on the front part of the bolt.
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Old 06-25-2014, 12:02 PM #11
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In the box that says Irony's suggested way there are 3 green dots which i assume are orings... tive located two of them byt the one furthest to the right is not on my bolt system. it looks like it would be on the inside of the bolt where the rear sail is...


Using the HPR air to "recock" the bolt faster...would that take away some adjustability in the LPR?
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Old 06-25-2014, 12:44 PM #12
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Quote:
Originally Posted by Razgriz2006 View Post
In the box that says Irony's suggested way there are 3 green dots which i assume are orings... tive located two of them byt the one furthest to the right is not on my bolt system. it looks like it would be on the inside of the bolt where the rear sail is...
That's the one you'd have to machine the gland for if you want to mod it that way, otherwise the LP air would bleed into the fore section when the solenoid switches on to cycle the bolt.

Quote:
Originally Posted by Razgriz2006 View Post
Using the HPR air to "recock" the bolt faster...would that take away some adjustability in the LPR?
It shouldn't, since the bolt would snap back for the first part of the rearward travel at the HP feed's pressure, but stabilize down to the LPR's pressure about half way back. Since the HP feed switches off so quickly; only a minuscule amount of HP air would be used. This would close the valve super fast and avoid excess air being dumped, while retaining the smooth shot the quest is known for.

The downside is that, if not done correctly, the bolt may close so fast that you may need to raise the pressure a little more (louder pop) or open the valve ports up a bit further to the front (lengthening the mechanical dwell of the valve) to offset the valve closing faster (in which case you can run a lower OP).

If you run some numbers on the forces/flow rates, you should be able to come up with a decent balance (number and size of holes) that will allow you to gain the most efficiency without having to lengthen the valve's dwell (less efficient).

If you remove the valve chamber shutoff, the pressure will drop less in the chamber while the bolt cycles, allowing a lower OP as well.

Last edited by tacxplosion : 06-25-2014 at 01:29 PM.
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Old 07-09-2014, 08:06 PM #13
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My more used bolt developed a stress fissure in the middle oring gland. If I would have continued to use this bolt it would have broke on me.

The plans for modifying this bolt just went up in stress cracks. Damn
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Old 09-01-2014, 10:40 PM #14
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