GX CS4 Compressor - Initial Impressions

I recently obtained a GX CS4 compressor direct from GX Pumps. They shipped quickly and it arrived a couple days later, well packaged and in good condition. It came with an assortment of tools, seals, rings, o-rings and springs, so looks like it has the parts needed for a complete rebuild, if needed. Based on other comments here, I flushed the cooling system with distilled water, drained it and refilled with a 50/50 pre-mix of Dexcool anti-freeze.

I ran a quick pressure test and was quite impressed with the speed at which it reached 400 BAR/5800 PSI! It's also very quiet, in fact, it's the quietest compressor I've ever owned and I've had quite a few over the years! Here's a quick video of the pressure test so you can here it running and see how fast it reached it's max capacity:


This is a 4 stage compressor running at a fairly low RPM, yet it makes nearly 10 BAR of pressure per stroke!

After ensuring everything was operating correctly, I filled my LSC SK-19's 580cc tank from 150 BAR to 250 BAR. This fill only took about a minute and the temerature of the compressor barely rose 4 degrees!

I did add a temperature Gauge, not that it's needed with how cool this compressor runs, but I just like seeing what's happening when filling!

View attachment 341675

Here are some pictures of what's under the hood:

View attachment 341677

This is the 4 stage compression chamber with cooling fins covering the entire outer cylinder.

View attachment 341678

This is the 350X motor driving this beast and providing cooling air to the radiator.

View attachment 341679

The auto shutoff pressure gauge is really top notch! Much nicer than what comes on most lower end Chinese compressors. It has 2 set needles, I'm assuming one is a back-up in case thefirst doesn't work. I set it at 400 BAR. The second I set at my desired fill capacity. I will say I have found the gauge to be very accurate, much more so that most of the compressors I have owned.

View attachment 341680

This is the resivoir for the cooling system. The whole self-contained system hold about 1 liter of water/coolant.

View attachment 341681

Here's another angle of the radiator.

View attachment 341682

Here is the burst disk and grease pot, both these are accessible with the cover on the compressor.

View attachment 341683

The intake filts elbow was swing loose when I first opened it up, so I snugged it down so it wasn't loose. I'm not sure what the white part is attached to the head, but think it might be a temperature sensor.

View attachment 341684

Here is the main controller board.

View attachment 341686

When you remove the top of the grease pot, you can see the grease inside. The manual says to turn the knob on the top of the grease pot one full turn every 4-6 hours of operation. I need to contact GX and ask what type of greese to use, just to have some on hand if needed down the road.

View attachment 341687

The rest of the grease inside the grease pot.

View attachment 341688

This is how it looks with the cover on it, you can see the knob has arrows showing the direction to turn it when needed.

GX Claims this compressor has a 5 hour run cycle and is rated to fill up to a 6.8L air tank! Seeing that the temperature gauge barely moved when topping off the 580cc tank on the SK-19, I have no doubt that heat is not a huge problem with this compressor!

Amazon is selling these for $699.99 plus tax, but buying direct from GX Pumps, you can save over $100! They are currently on sale for $659.99, but by using the coupon code [GXPUMPS10OFF] it brings it to $593.99 shipped.

Thus far I am really quite impressed with the feature of this compressor for it's price point! It seems very solid and built to last. If interested, check out what they offer direct, they seem to alway have several different models in stock and on sale!


If you have any questions, please post them below and I'll try my best to answer them.
I’m interested. Just to fill a small bottle what is your time on a empty 500cc to 3600psi?
Or a 1-9 liter if you know please.
I doubt it would fill a big 6.8-9 in less than 4 hours
 
Well, going to see for myself. Made the decision!!!

Screenshot_20240117_120757_Gmail.jpg
 
  • Like
Reactions: Dewy and FLgunner
I'm using one of the small cotton filters, like what came with the YH compressors. I have checked it after filling several guns and it doesn't even feel damp. And, unlike the YH compressors that quickly soiled those filters with oil blow by, it's still just as white as the day I installed it! I'm not sure it's really needed...
 
I tried mine for the first time today. Testing with just the hose it went from 0-300 bar in about 27 seconds. Impressive! Filling my leaky Impact’s .48L cylinder from 50-250 bar took almost 11 minutes though. The leak that gun has now is pretty slow so that probably didn’t have a lot to do with the fill time. I had to use an adapter with a longer female fitting since the fitting on the GX CS4 hose is a little too short and bulky to fit on the Impact’s quick disconnect. There was some slight leakage between the compressor’s fitting and my adapter at first so that may have extended the fill time slightly. I filled that same reservoir from 0-250 bar once with my Hill EC-3000 compressor. I don’t remember how long it took but I remember the compressor had to stop partway through because it got too hot. I don’t see that being a problem with the GX CS4. I think it will be a good portable compressor to have.
 
  • Like
Reactions: W.Sheid and Dougie
I tried mine for the first time today. Testing with just the hose it went from 0-300 bar in about 27 seconds. Impressive! Filling my leaky Impact’s .48L cylinder from 50-250 bar took almost 11 minutes though. The leak that gun has now is pretty slow so that probably didn’t have a lot to do with the fill time. I had to use an adapter with a longer female fitting since the fitting on the GX CS4 hose is a little too short and bulky to fit on the Impact’s quick disconnect. There was some slight leakage between the compressor’s fitting and my adapter at first so that may have extended the fill time slightly. I filled that same reservoir from 0-250 bar once with my Hill EC-3000 compressor. I don’t remember how long it took but I remember the compressor had to stop partway through because it got too hot. I don’t see that being a problem with the GX CS4. I think it will be a good portable compressor to have.
Got mine on Friday last week, and my plug test took 24.3 seconds that could be good or bad I guess.
 
You may want to just replace the little disc with one of the spares that came with it and try it again. I'm not sure how scientifically calculated the burst point of those little discs really are. It may have weakened over time and a 2.5 hour run just pushed it over the top. I'm sure continued use puts a lot of stress of those discs.