GX PUMP GX-E-CS4-I PCP Air Compressor, Max 5800Psi,350W Powerful Motor

Excellent compressor! Has all the bells n whistles. Fast fill time. 68ci tank fill from 0-4500psi in 25 minutes. Have filled many tanks with great times. Can fill for 5 continuous hrs with no down time for large tanks. Big perk is it's extremely quiet! In addition has a grease pot which allows you to turn knob every 4-6 hours to lubricate the pump. Awesome feature! Have owned quite a few cheaper compressors n by far this one is superior. Costly but you get what you pay for. If your on the fence about buying this compressor it's definitely worth the cost. I couldn't be happier! Has good instructions with an itemized parts list which is great for if n when could need repairs. Don't anticipate that for a long time. Very pleased with this purchase! GREAT COMPRESSOR! Also has auto stop setting ability with a back up setting to your setting. Pump does not get anywhere near overheating due to the onboard water tank for great cooling of pump.

My experience with the GX-E-CS4-I Air Compressor is noted by these items: This unit was purchased and this review is based on my perceived value and the function of the unit. Features of this unit that influenced my purchase was quality construction, ability to fill 1.5-2 L bottles, availability of repair parts and ease of set-up. - Shipment was quick and well packaged. The compressor was in great shape when delivered to my door. - Very easy to set up with the written instructions. Just follow the steps and you're up and running in under 30 minutes. - The only assembly to this compressor was adding a coolant to the tank (I used anti-freeze) and connecting the hose. - I added the GX Pro Grade Filter while setting up the compressor for quality air delivery. This is something you should NOT skip if you are putting air into expensive PCP equipment. -Once I set the cut-off pressure and back-up pressure limit, everything performed without a hitch. I have now officially retired my hand pump and can fill my equipment and bottle without breaking a sweat. I'll update this review after using the compressor through the Summer. UPDATE 7/9/26: After running this compressor for over 3 hours total, I have a couple of numbers to run. Just filled up a 98ci (1.6l ) bottle to 300 bar and it took 42 minutes. For an FX DRS 700mm pcp it filled up to 230 bar in 9 minutes. No issues with the pump, filter or bottle.

At first, I was planning on getting one of those many $200'ish pumps readily available on Amazon. Many even look a lot like the $500'ish ones reputable airgun supply companies sell as their entry level "branded" recommendations. Upon further research, I decided to spend more to get significantly better specs and happy that I did. This one lists a MUCH longer run times (like over 5 hours, the others are like 10-15 minutes at a time), so it CAN fill bottles (still skeptical so not likely to be used as such for me). It is also significantly quieter (based on online reviews and videos of the others). Its noise is literally a FRACTION of even my regular air compressor for cars. It doesn't come with a temp gauge, like many of the other cheaper versions, but this one is water cooled - so it probably doesn't have a heat issue (definitely not even getting "warm" from my own uses). I'm not sure if it comes with a water filter (claims to have one internally) so I got a separate filter (from them). Specs are overkill for my intended uses (direct fill of air guns), but my gun has a max fill capacity of 3 bars, and this one actually is capable of going to 4 bars (the cheaper ones are all 3bars). This might have been the only one I've found that is specced to 4 bars at this price point. Works exceptionally well, doesn't rattle like its overworking itself, is quiet enough to use in the house, and appears to have a good build quality. I think the cheaper ones may be a good alternative to the hand pumps (some actually costing the same surprisingly), but this one appears to be built to last a bit longer (especially if intended to be used casually like I am). Replacement parts seem to be available (but at this price point, I wouldn't be disappointed to have to replace after several years of use). I did have an issue with the water filter I bought separately (hookup error) and the support was immediate, real time, and helpful (same company), so the company has some credibility as well.

I have a Nomad II that broke down after two years. I had to repair it a few times since, so I wanted to get a new PCP air compressor and keep the Nomad II for backup. After doing my research, I decided on the GX CS4i. This compressor cost less than the Nomad, but in my opinion is way better. Faster fills, water cooled, longer run times, quiet, and a higher PSI fill rating. I did have one minor issue at just under a year of ownership, the water pump went bad. I check to see if it was getting voltage to the water pump, which it was so I contacted GX Pump customer service. I received a new water pump shipped from China two weeks later. That fixed the issue. It's not their fault that a vendor's supplied water pump went bad. Taking care of the customer, that's what counts. I don't think you will find a better PCP air compressor then this one for under a $1000. Also, their new GX Pump PCP compressor oil/water separator filter is another great product.

Haven't used it much but if your looking for fast and quiet this is it..I bought this for my paintball tanks that are up to 80ci 4500psi bottles. It will fill it full in around 23min. I tried smaller compressors and they just stop working after a few long waited fills or they will only fill to 1500psi then stop, then never work again.

Item appears to be used. The information about this item on Amazon clearly states that "Note: before first use, it must be filled with 500ml of neutral distilled water or antifreeze", but this unit was full after only 150ml, so I took off the cover to see why (see pictures 1 & 3). It simply had been filled before and not completely drain. The fill cap for the coolant tank was extremely tight and the tank had visible rust inside at the bottom. Now, the compressor appears to be well made, and the accessories appear new, but the unit clearly appears to have been used. Two of the screws on the cover appear to have been stripped (hard to believe the factory did this but possible), but the converter (as seen in pictures 2 & 4) clearly has been fingerprints all over it. Once again hard to believe that this was done in a clean manufacturing environment, but possible. I returned this unit and order hopefully a "new" one. I received the second "new" compressor, and it was full after 250ml of antifreeze?!@ Now, it is possible that the distributor is filling each compressor and quality checking each prior to shipping to Amazon, but that is hard to believe because they left the cooling system three fourths to half full on these two compressors respectively. Now, I am going "try" this allegedly new unit and if it performs well keep it, but I have not been able to find the warranty on this compressor? At this price point and no warranty information? That is cause for concern, but once again your mileage may vary. UPDATE: After studying the CX CS4-I cooling system, I believe if the compressor is run on it's right side (the unit has feet on the right side) that the cooling cavitation issue would be solved or prevented (the inlet would be at the top and the outlet at the bottom of the radiator). This would allow heated inlet at the top and cooled outlet at the bottom of the radiator respectively, and cooled inlet on cylinder head lower than the heated outlet which would be higher (best for efficiency). My only concern would be the built-in oil-water separator being gravity assisted due to it's placement in the case that may need to be vertical in it's orientation. If this was an automotive cooling system then the upright running of the compressor would cause cavitation issues because both inlet and outlet are at the bottom of the radiator (and the inlet on the head would be at the same height as the outlet which is not ideal), part of which could solve by rotating the radiator 90 degrees counter-clockwise if you decide to run compressor in the upright position (vertical) but would not address the inlet and outlet on the head being the same height. Pictures 6 & 7: The blue arrows indicate cooled water and the red arrows indicate heated water . . .. the solution . . . lay the machine on it's right side (which has feet, so someone was planning on it) and the cooling system has no cavitation and is in it's most efficient configuration. Picture 8: Red arrow - cooling tank, orange arrow - compression cylinder, green arrow - gear box, blue arrow - electric motor, yellow arrow - cooling tank. Solution, lay the box on it's right side and cavitation (air pockets) is prevented, and system is at peak efficiency for cooling. SECOND UPDATE: It is not recommended to run the compressor for any long period of time on it's right side because the unit uses a gravity-assisted oil-water separator (which is quite common in many compressors in this category). The purpose of this separator is to remove both oil and water from the compressed air to ensure that the air reaching your air gun or tank is clean and dry, preventing damage or degradation. This unit has an orientation limitation due to separator's gravity dependency because a vertical oil-water separator relies on gravity to help the oil and water separate and settle. In a horizontal orientation, gravity would not work in the same way on the air stream. The oil and water droplets would be suspended in the airflow, and they wouldn't have a clear direction to settle. This would likely result in poor separation and could cause both oil and water to remain in the air stream. I believe that if you run the unit for 10 minutes on it's right side (horizontal position) that would purge the unit and prevent cavitation but then run the unit in the vertical position, so the separator works properly. THIRD UPDATE: But after more research I believe I found the best solution and that is to turn the radiator 90 degrees counter-clockwise, and I can say it will work with the GX CS4-I, it is a close fit on the right side (viewed from the front) because of the built-in 110v to 12V DC converter has limited clearance. The left side with the radiator inlet and outlet cleared without incident. When I refilled the coolant, the radiator slowly purged itself with the compressor off. I then ran the unit, and the pump head purge itself and I was able to add more coolant than I took out (about 25 mils plus or minus). I was using automotive cooling systems as a guide, but if you look closely, you will see that I hookup the warm inlet at the bottom and the cool outlet at the top of the radiator, because of cavitation (air pockets). The opposite of normal automotive cooling . . . because of the water pump in this compressor not producing enough pressure, it is not like automotive pumps working in a closed high-pressure system. This compressor uses an open non pressurized system with low pressure aquarium pump . . . therefore, fluid dynamics would be controlling, and air bubbles (pockets) rise in coolant and the outlet being higher than the inlet would be self-purging (and not rely on higher pressure from pump to purge the cavitation), which it now is. NOTE: The pictures are not in proper numerical order due to updates (my pictures order was changed). Fourth Update: I have two separate shooting locations, so I own two FX Impact M4 Snipers and have mirrored the setups at both. I recently purchased another GX-E-CS4-I compressor and had to return it immediately. It was leaking air straight out of the box, and several accessories were missing (the box appears to have been previously opened). I’ve now had bad luck with multiple units from this brand. In theory, these compressors should be perfectly adequate for my needs since I only fill one airgun at a time. I’m going to step up to the higher-end models and see if I have better results. Once, GX improves their quality control, these should be excellent compressors at this price point. Unfortunately, that hasn’t been my experience so far. Your mileage may vary. Fifth Update: Okay for Father's Day I was given a newer version of this machine . . .. I have to say they fixed the radiator issue (rotated it 90 degrees) and added a hour counter 000001.00 (down to 1/100 of hour). This now represents the most compressor at this price point. The last three pictures are the new updated machine. They update the coolant lines, the fittings from the cylinder head, and maybe more. The fit and finish is better than the last three machines. It you need one . . . this is the best I found at this price point. Time will tell about the longevity.

I love this pump. clean two stage compression. pump never gets hot or bogged down even at 5800 psi. plenty of power. safe, redundant safety features. easy to read and set pressure gauge. took the cover off to look at the internals, great build quality though out.

I first bought a cheaper compressor, but it started to fail in the first couple of weeks, so I decided to not mess around with inexpensive ones and got this one; It has been working fine, is quieter and faster than the small inexpensive one.

Molto bene grazie mille

I owe already CS4 model (without -I, this one is CS4-I). Again a very good product that can work in a long session and effortlessly can reach 300 Bar, the pressure I need for my PCP gun. This model produces less noise and has 220 V power supply integrated in the unit, so no external one is needed. You can also connect 12V directly to the unit, the same as for CS4. I am happy with both products.

Wow, this Compressor is awesome, its so easy to set up, (tip: buy some distilled water at the same time, its required for use) Its a solid little unit, i though it was going to be way bigger and heavier than it is. Its so quiet, especially compared to my old Heug Yeug Compressor, which did a great job for 7 years with no hassle. But wanted an all in one upgrade with no buckets of water etc etc. This compressor is quality, customer service from GX has been Awesome as well, I emailed them about a warranty and they replied in less than an hour, and said even outside of the 1 year warranty, we're always happy to help with any issues. It fill my bottle from 200bar to 300 in no time at all and turned off when finished. Its an expensive item but well worth it.

Enfin un compresseur de qualité. C'est le premier qui me permet de charger consécutivement 3 bouteilles de 1l de 0 à 300 bars sans pb. Je vous le recommande pour plongée. La séparation de l'eau se fait très bien et je n'ai ni eau ni graisse sur le filtre que j'avais rajouté ! L'eau se purge automatiquement lors du cassage de pression, en fin de gonflage (par le petit tuyau destiné a cet effet). Enfin un compresseur qui tient ses promesses. Pour ma part je l'utilise avec du liquide de refroidissement de voiture (qui contient de l'antirouille) car j'avais utilisé de l'eau distillée sur un précédent modèle et il y avait eu un encrassement et de la rouille sur le bouchon. Et la dissipation thermique se fait sans pb. En plus il n'est pas très brillant. Vraiment il vaut son prix. 1 an après, je suis toujours extrêmement satisfait de ce modèle. Il faut bien noter le nombre d'heure d'utilisation pour ne pas risquer de sur graisser la machine. Vraiment content.

Deze compressor is voor een compressor van dit formaat zeer stil en je kunt gewoon je gesprek met voortzetten als er natuurlijk iemand bij je is wanneer je het geweer gaat vullen. Deze compressor gebruik ik om mijn 6.8liter fles te toppen elke keer van ongeveer 200bar naar 330bar en daar heeft deze compressor totaal geen moeite mee en ik heb 2 extra temperatuurmeters opgezet en wel op beide leidingen van de koeling om gewoon zeker te zijn dat te temperatuur goed blijft en de temperatuur van de koeling komt niet boven de 40graden tijdens het vullen van de fles. Dit is echt een zeer fijne compressor. Een belangrijke tip voor alle gebruikers, gebruik wel een extra filter en plaats deze dan Vertikaal want dat kleine filterunit wat er standaard bij zit is niet voldoende.