• The AGN App is ready! Search "Airgun Nation" in your App store. To compliment this new tech we've assigned the "Threads" Feed & "Dark" Mode. To revert back click HERE.

Extreme Booster Pump

I recently took delivery on an "Extreme Booster Pump" and tried it out. The first problem I was faced with was no means of measuring the high pressure output. This booster doesn't come with a pressure gauge and neither does my "Western Big Bore Bushbuck" rifle. If I'm not mistaken, "Extreme Big Bore" rifles don't have pressure gauges either. How in the world does Extreme expect people to use these boosters ?

I purchased a good quality pressure gauge from McMaster Carr and installed it on the high pressure side of the pump and now at least I can see the pressure. Everything seems to work. It's disappointing that Extreme doesn't install a pressure gauge, or at least offer the option for guns that have no gauges.. I saw a photo of an earlier version of the extreme booster pump and it had gauges on both the low & high pressure side.

Beware, this booster pump doesn't come with any documentation. At least mine didn't. No instructions, parts diagram, warranty information, nothing. No part number or model number. I assume there is a warranty because when I talked to extreme about adding a pressure gauge, I was told that If I modify the pump by adding a gauge I will void the warranty. I suppose the safe thing to do is install the gauge downstream in the hose, but I hard plumbed mine by adding a tee fitting to the pump.
 
The Altaros booster looks interesting and I wish I'd known about it earlier, but I already bought this Extreme booster. It seems to me I should be able to make this booster work. I've been studying it closely and it looks like there are the two problems with this pump. 

1) When the the pump piston retracts there is backflow on the high pressure output causing a pressure drop. I think there needs to be a check valve to maintain the pressure in this line.

2) The pump action is much too fast. You can't slam air into the gun reservoir this fast and this creates those pressure spikes. There might be a restrictor in the gun to slow the fill rate. Ideally there should be a slow steady increasing pressure which allows the gun air tank and pump output to reach equilibrium. A metering valve installed on the low pressure side of the pump to the air powering the large piston should allow speed control to slow the pump action.

With the addition of check and metering valves as described, I think the pressure spikes will disappear and it will become a steady increasing pressure without pressure drop. The pressure gauge on the pump should then accurately indicate the pressure in the guns tank.

I welcome comments or any advice.
 
The Altaros booster looks interesting and I wish I'd known about it earlier, but I already bought this Extreme booster. It seems to me I should be able to make this booster work. I've been studying it closely and it looks like there are the two problems with this pump. 

1) When the the pump piston retracts there is backflow on the high pressure output causing a pressure drop. I think there needs to be a check valve to maintain the pressure in this line.

2) The pump action is much too fast. You can't slam air into the gun reservoir this fast and this creates those pressure spikes. There might be a restrictor in the gun to slow the fill rate. Ideally there should be a slow steady increasing pressure which allows the gun air tank and pump output to reach equilibrium. A metering valve installed on the low pressure side of the pump to the air powering the large piston should allow speed control to slow the pump action.

With the addition of check and metering valves as described, I think the pressure spikes will disappear and it will become a steady increasing pressure without pressure drop. The pressure gauge on the pump should then accurately indicate the pressure in the guns tank.

I welcome comments or any advice.


1) What you see is the difference ie. overpressure between booster and valve in the gun. It will never be 100% efficient as there will always be a slight difference between the sides of a one way valve.

2) You can adjust the regulator for the LP piston and when you lower pressure you lower working speed. (At least i think you can adjust the regulator). The big brass thing on the LP side. The altaros will boost past 400bar~6000psi on merely 5-6bar~75-90psi working pressure.

If you insert a "regulator", think a valve like a water faucet on the LP side then you get the same working pressure but at a slower rate and that will eleminate most (all) of your HP pressure spikes. Same work at a slower pace.



I think you're overthinking the "spike" thing, if it was a problem then it would have been a problem a long time ago and delt with in a proper way.

And no there is no restrictor in the gun, just a simple one way valve.



As to pressure gauges: If you fill your gun to what it likes and can read the small pressure gauge then what more do you want?

A 3" gauge will most likely be more presise and easier to read but you still only fill to what the gun likes.



Did it help you to be a master of boosters ? ;-)
 
Chickenthief,

Thanks for your input. You're right, I have been overthinking it. What it really comes down to is pretty simple, with a little more understanding of how this pump works. I found a little more information.

The big drop in air pressure is the return stroke of the piston. Due to the lack of a check valve on the pump output side, the pressure drops. I'm seeing a drop to near supply pressure with each return stroke. There is nothing wrong with this as it is simply using the check valve of the gun to capture the pressure and they saved the cost of a check valve, but if you want a steady pressure that's easier to read at the pump or in the output line, you need the additional check valve. In my case the gun has no pressure gauge so I need a gauge on the pump output and it would be great to eliminate this pressure drop. Not really necessary, just a preference.

I noticed that the earlier version of this pump had the same brass pressure regulator but on the output side it also had a flow control valve so you can adjust the pump speed. They probably eliminated it to reduce cost or thought it unnecessary. It would be nice to have this adjustability. You could set the pump speed according to preferences.

If my gun just had a simple pressure gauge there wouldn't have been an issue here. With a little more understanding of this pump I now have it working. Too bad it didn't come with some instructions.