Low velocity with MQ

u238 · 01-15-2009, 08:14 PM

I just installed my MQ, and though I haven't chronographed, the velocity is visibly low. I have the pressure at the point where the valve will begin to leak, and it still does not bring up the velocity enough. The white spacer is removed, but since I have a full body gun I doubt it is needed. I tried holding the bolt forward to check for the bolt blowing back with no success. What other possible causes of low velocity are there?

Fearless_Leader · 01-15-2009, 08:29 PM

what is your coff setting?

loneassassin · 01-15-2009, 08:47 PM

Low battery will definitely cause low velocity. Even if your indicator says it's fully charged, it still may be low enough to cause a loss of velocity. That's the first thing I'd check.

Second, is your bolt upside down? Lol, just thought I'd ask.

Thirdly, what are your settings? I use a dwell of 4 milliseconds. (Son: 4ms.)

Finally, is the poppit lubed with Dow33 or an equivalent lube? That will also affect velocity. You might also just need to break it in a little.

I think you already checked this, but a common mistake when setting up MQ'd guns is to adjust the lpr way too low, and then your shots are actually blowing the bolt back as well as propelling the paintball. Try it with an pretty high lpr setting just to rule that out. Better yet, use a high lpr setting and a low inline reg setting, and slowly increase your inline pressure while shooting over a chrono.

u238 · 01-15-2009, 08:48 PM

COFF: 30ms
D/DEL: 4.1ms
SON: 4ms

The battery is new. The valve set screw protruding too far in can cause low velocity, right? I may try filing it down.

Edit: Now that I think of it, I'm not actually 100% certain that the battery is new. I only know that it worked with my Karnivor before MQ installation, and that the board says it is new. We all know that the MQ is sensitive and the board lies, so I will try a new one and report back.

Fearless_Leader · 01-15-2009, 09:02 PM

Maybe if the valve screw was not allowing the valve to open all the way. Just back it out some if you are worried.

Lube the valve would be my guess.

loneassassin · 01-15-2009, 09:05 PM

The valve set screw could be interfering with the poppit's movement if you screwed it in too far. I use blue loctite on mine, and stop when it is just beyond flush with the bottom of the gun body. It's really just there to block air from coming out the bottom of the valve, and to keep the valve body from rotating out of alignment.

hmcl281 · 01-15-2009, 10:09 PM

do u know fore sure what the reg pressure is?

u238 · 01-15-2009, 11:52 PM

Quote:

Originally Posted by loneassassin

The valve set screw could be interfering with the poppit's movement if you screwed it in too far. I use blue loctite on mine, and stop when it is just beyond flush with the bottom of the gun body. It's really just there to block air from coming out the bottom of the valve, and to keep the valve body from rotating out of alignment.

My set screw won't thread in past flush at all. I just fired a bunch of shots on my supposedly new battery then tested it. It was putting out 8.5v

Edit: Still no luck. I can't get past 260fps without a leak. To clarify, a leak from the barrel / poppet is caused by low pressure, while a leak from the pilot is caused by high pressure, right?

loneassassin · 01-16-2009, 07:32 PM

Are you sure that your valve port is lined up perfectly with the hole into the top tube. (It should also be perfectly lined up with the set screw hole.) That could affect velocity.

Also, if your bolt is too small, you might be losing some velocity. How's your paint to bore match?

u238 · 01-16-2009, 08:36 PM

Quote:

Originally Posted by loneassassin

Are you sure that your valve port is lined up perfectly with the hole into the top tube. (It should also be perfectly lined up with the set screw hole.) That could affect velocity.

Also, if your bolt is too small, you might be losing some velocity. How's your paint to bore match?

The valve is lined up correctly. My bolt fit is perfect as is my paint to barrel match. I wonder if the 5 degree F temperature makes the MQ leak at a lower pressure.
I really hope I can get this sorted out. I don't want to put the white spacer in to gain velocity. Battery life is already poor enough.

dec7td · 01-16-2009, 10:21 PM

How long is your marker in the weather before you start shooting?

u238 · 01-16-2009, 11:44 PM

Quote:

Originally Posted by dec7td

How long is your marker in the weather before you start shooting?

Not very long. Only the time it takes me to walk outside and set the chronograph down.

Fearless_Leader · 01-16-2009, 11:50 PM

put the white spacer back in?

dec7td · 01-17-2009, 08:50 AM

I would say try the white spacer as well. As a last resort measure you can try stretching the pilot spring out a bit.

loneassassin · 01-17-2009, 09:06 AM

Quote:

Originally Posted by dec7td

I would say try the white spacer as well. As a last resort measure you can try stretching the pilot spring out a bit.

I don't see how that would work. Removing the spacer, and having less spring tension means that your actual dwell is longer, which should increase velocity.

dec7td · 01-17-2009, 11:17 AM

Putting the white spacer in will allow the MQ2 to operate at a higher pressure which might help his cause. At least that's my logic

u238 · 01-17-2009, 02:03 PM

I guess I'll have to put it back in. I just don't see how a full body gun won't work without it. It's strange that before I replaced the valve and regulator, I couldn't get the velocity past 260 either. I would say it's too unusual to be a coincidence, except that there isn't really anything else that would affect velocity.

uberPHAGE 2 · 01-17-2009, 02:16 PM

yeah there is. valve size. valve chamber size. reg. minied or not. vert ASA holes. battery. spacer in or out. valve set screw too far in. pinched wire. in non mq guns, hammer wieght and spring tensions. lots of factors

u238 · 01-17-2009, 05:38 PM

Quote:

Originally Posted by uberPHAGE 2

yeah there is. valve size. valve chamber size. reg. minied or not. vert ASA holes. battery. spacer in or out. valve set screw too far in. pinched wire. in non mq guns, hammer wieght and spring tensions. lots of factors

I meant in my particular gun.

dbkid0486 · 01-17-2009, 06:00 PM

Quote:

Originally Posted by u238

I meant in my particular gun.

almost everything that he mentioned is in your particular gun is it not?

Stealthymidget · 01-17-2009, 07:09 PM

Quote:

Originally Posted by loneassassin

I don't see how that would work. Removing the spacer, and having less spring tension means that your actual dwell is longer, which should increase velocity.

Stretching out the spring will allow the plunger to hold a higher pressure. What happens when you charge the noid? The plunger is pulled away front the vent hole and there is less pressure at the tip until it isn't touching at all. Stretching makes the spring longer so more pressure and a higher vent pressure. Also, make sure the paint/barrel match is near perfect. Too big of a bore will allow roll-outs and low velocity.