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The best way to increase CFM on an air compressor is to make some adjustments to your system such as adding another compressor pump or an air receiver tank for extra storage. Some tools require CFM ratings greater than your air compressor’s rating in order for them to successfully operate.
Here you’ll find recommendations on how to adjust your compressor so that you can reach your desired airflow rate (CFM).
Table of Contents
- How to Get More CFM Out of Air Compressor
- How to Increase CFM on Air Compressor
- FAQs (Frequently Asked Questions)
- Reader’s Questions Answered: Increasing Air Compressor CFM
How to Get More CFM Out of Air Compressor
To increase the CFM that you can draw from the outlet of your air compressor you have 2 main options; 1. increase the pumping capacity of your air compressor system or 2. Increase the air storage capacity of your system.
To be clear, none of these options will increase the inherent DESIGN specified CFM of your original compressor – that would take pump modifications.
You’re not actually interested in increasing the CFM of your compressor PUMP (which is what’s specified in the user manual) what you’re actually interested in is increasing the CFM you can draw from the OUTLET of the air compressor tank – to allow you to run an air tool that has a higher specified working CFM than your compressor PUMP.
I explain this concept of CFM of the air compressor pump vs CFM of the whole air compressor system in my article explaining how to calculate CFM of an air compressor system.
If you’re confused as hell about CFM, it’s probably worth reading my article; what is CFM?
Whether you add more pumping capacity to your air compression system or more air storage capacity will depend on whether you have an intermittent or continuous demand for air for your air tool.
Increasing CFM for Cyclical or Intermittent Air Tool Use?
If you have short periods, intermittent, or a cyclical high demand for CFM that isn’t continuous you have more options for increasing CFM. Ultimately adding air storage capacity will enable you to increase the CFM of the system for a period of time dependent on the level of air storage.
Increasing CFM for Continuous Air Tool Use?
If you have a more continuous demand for a higher CFM (continuously running the air tool), your compressor pump CFM will need to match the demand of the air tool. Adding extra air storage capacity to the system will therefore not be a suitable option and you’ll be limited to options that add more pumping capacity (CFM) to the system.
Air Compressor Continuous vs Intermittent Running
Regardless of the cyclical, intermittent or continuous use of air tools connected to your compressor, it’s important to note that your air compressor will likely be designed for “cyclical operation”. When I talk about cyclical or continuous use above,
I am talking about the AIR TOOL.
The air compressor will be designed for periods of operation (pumping) followed by periods of idling (cooling down). This is called an air compressor duty cycle, which is typically expressed as a percentage, such as 50% – which means the compressor needs as much time cooling as it does when operating. Find out more about air compressor duty cycles in my comprehensive guide to compressor duty cycles.
How to Increase CFM on Air Compressor
Best methods for increasing CFM on air compressor systems:
- Decreasing the pressure to increase CFM
- Adding another compressor of the same CFM
- Connecting two compressors together of differing CFM
- Adding another air receiver tank
- Increasing the size of the existing compressor
Decreasing the Pressure to Increase CFM
With the air pressure being built inside the air compressor, it is then forced out the outlet at a certain flow rate (CFM – volume/time). Every compressor has its power rating, and this power is equal to the pressure multiplied by CFM (air flow rate). As you cannot easily increase the compressor’s power beyond its limit, reducing the pressure in the system by dialing down a regulator will cause the CFM to increase – power remains constant.
If you’re familiar with air compressors, you may have already looked at this option before searching for ways to increase your air compressor CFM. However, many compressor users don’t realize that your compressor OUTLET CFM is variable based on the outlet pressure that you set.
If you have a compressor that’s rated at 4 CFM at 90 PSI, you can probably run a tool with a continuous demand for a CFM of 5, or even higher if the WORKING pressure required by the tool is around 40 or 50 PSI.
This is because, at the outlet of your air compressor tank, there is an inversely proportional relationship between CFM and PSI (within certain bounds).
So pay attention to your air tools’ CFM rating and their working pressure – it’s possible that the working pressure may be lower than 90 PSI, so you might be able to get an instant boost in CFM from your existing compressor.
Considerations of Decreasing the Pressure to Increase CFM
- Suitable for continuous use of air tools (as long as compressor CFM exceeds tool CFM demand)
- Suitable for intermittent use of air tools
- The most cost-effective solution – it’s just adjusting your compressor
- It relies on your air tool having a sufficiently lower working pressure than 90 PSI (as CFM ratings are typically specified at 90 PSI)
The relationship between CFM vs PSI is complex, so calculating the CFM your compressor can deliver at a lower outlet pressure could be extremely difficult – and unreliable. Try not to rely on this method for drastic increases in CFM (say more than 20-25%).
The CFM of your compressor at the lower pressure still needs to exceed the CFM demand of your air tool if the tool is to be utilized on a continuous basis.
Therefore, when it comes to continuous use, this methodology is limited to scenarios where your existing compressor is in fact capable of delivering your required CFM but at a lower outlet pressure than the standard compressor CFM rating at 90 PSI.
You may still be able to get away with an underrated compressor in terms of CFM at a lower pressure. If you’re not continuously drawing down a higher CFM than your compressor pump is capable of providing, your compressor tank will act as a reservoir allowing your compressor to “catch up” between AIR TOOL use cycles. But be careful not to exceed your air compressor duty cycle!
So even if this methodology gets you halfway to closing the gap between your compressed airflow demand and your compressor’s ability to supply, this might just be enough for many cyclical air tool use applications.
Adding Another of the Same Compressor to the System
Adding another compressor of the same CFM, brand, and model can help double your current air compressor CFM rating without adding control complexity.
This method increases the CFM of the air compressor pumping system, whilst also enabling a higher CFM at the air compressor tank/air pressure regulator outlet.
Once you have your duplicate air compressor in place, you can quite simply connect the two compressors together using some compressed air line and a T-piece air fitting. You then can plug your air tool or airline leading to your air tool into the outlet on the t-piece.
As the air compressors are the same make, model, and size, they’ll have the same cut-in and cut-out pressures set on their pressure switches, meaning there’s no synchronizing of control issues to overcome… great!
Considerations of Adding Another Compressor of a Similar CFM
- Great for continuous air tool use applications – the air compressor system has a higher CFM
- Suitable also for intermittent air tool use
- Not as cost-effective as a second compressor is purchased
- Pressure switches should be identical, but manufacturing variations could mean some adjustment might be required to sync cut-in and cut-off pressures
- Still need to check the DUTY CYCLE of the air compressors to size the air compressors correctly in relation to the air tool working CFM
A duplicate air compressor might be a more drastic approach to increasing your CFM if you haven’t got a continuous demand for higher CFM.
For example, a compressed air tank with a 5-11 gallon capacity, like this one from Performance Tool might cost you a fraction of the cost of a brand new second compressor – and still solve your low CFM problem (for short periods of continuous use).
Applications such as operating air wrenches and framing nail guns are examples of where a high CFM rating air compressor would be required for continuous use.
Connecting Two Compressors Together of Differing CFM
Similar to the last suggestion, but now focusing on connecting 2 air compressors of differing CFM, make and model. It’s as simple as it sounds. Not the process, but the concept.
If you have two compressors that have a 10 CFM and 5 CFM rating respectively, then connecting them together will give you 15 CFM of continuous flow rate.
The process of connecting the 2 compressors together involves the following steps:
- Connect the outlets of the air receiver tanks using a t-piece air fitting
- Connect your compressed air hose to the outlet of the t-piece
- Connect your air tool to your air hose
Example T-Style Air Manifold for connecting 2 compressors together:
Considerations of Connecting Two Compressors Together of Differing CFM
- Great for continuous use of air tools – the pumping capacity of the system has a higher CFM
- Suitable for intermittent air tool use
- Not as cost-effective if buying a new air compressor
- Could be more cost-effective if you’re using a spare compressor or borrow from a friend or neighbor
- Adjustable air compressor pressure switches will be required
- Still need to check the DUTY CYCLE of the air compressors to size the air compressors correctly in relation to the air tool working CFM
Controlling Cut In of Two Different Compressors
Operating 2 different compressors of differing sizes, power, CFM, and even pressure can be a tricky business. It’s likely that the pressure switches for each compressor will be set to cut in at different pressures.
Now that the compressors share a storage volume (as their tanks are connected with a hose) the pressure in the system as a whole will trigger each compressor to cut in.
If the cut-in pressure of one compressor is 80 PSI and the other 90 PSI, the second compressor won’t cut in until the system drops below 80 PSI – and this will happen whilst the compressor that cut in at 90 PSI is working.
This is a control system issue – to prevent one compressor from doing all the work and ultimately yielding the true potential CFM of the system, you need to have the cut-in and cut-off pressure set the same.
This might mean you need to fit adjustable pressure switches to both compressors and synchronize them with a bit of manual work.
If you’re wondering how to adjust an air compressor pressure switch, I wrote a whole article dedicated to adjusting your pressure switch cut in and cut off pressure.
Adjusting the Pressure Switches
You must consider the pressure switches on both compressors, and if they have similar cut in and cut out points. If they do, then they will work approximately the same amount depending on your air tools’ air demand.
If you have a gap in the cut in between the two switches that are too big, however, one compressor will be doing all the work, starting and stopping much more frequently than the other. This will lead to increased maintenance requirements and potentially a short life span.
And, this ultimately lowers your peak CFM as the peak CFM is achieved when:
- The tank is 99% full
- Both compressor pumps are operating just prior to cutting out
If the system is 99% full and only the 10 CFM compressor is operating, the actual peak CFM capability of the system is equal to the 10 CFM compressor, plus the delivery capacity in the air tank.
Whereas, when the system is 99% full and both the 10 CFM and 5 CFM compressor are operating – the peak CFM of the system is equal to 10 + 5 CFM plus the delivery capacity in the air tank.
Adding Another Air Receiver Tank
Adding another air receiver tank will allow for the air compressor to fill both tanks (one with the compressor + the one added) offering you far greater storage of air. This will mean that the air compressor motor will run for a longer period before reaching cut-out pressure and stopping, allowing you to use your tools for a longer duration.
The compressor pump is now filling a larger volume and thus you have a greater amount of CFM due to the larger reservoir of pre-compressed air waiting to be used for your high demand air tool (oversimplification as an increased tank size changes the available CFM for a period of time, not the CFM of the system).
This is by far my favorite solution for increasing the CFM of your compressed air system.
I specifically say “compressed air system” as it’s not true to say that adding a second air tank to a compressor increases the “air compressor CFM” – that’s If you take “air compressor CFM” to mean “air compressor PUMP CFM”.
The CFM available at the OUTLET of the compressed air tank (or the air pressure regulator) is actually separated from the CFM of the Air Compressor PUMP by having air tanks to store the compressed air in (within limitations).
So I can actually get 15 CFM out of an air compressor SYSTEM even when the air compressor is rated to 5 CFM – I just need a big enough set of storage tanks, and 15 CFM would only be available for a fixed period of time – as the air compressor PUMP wouldn’t be able to keep up with the demand.
In addition to that…
Adding a second tank to an air compressor will allow the compressor to have more cooling time (assuming you’re not drawing more CFM from the system than the compressor pump can generate). This is because there’s now a greater volume of air stored, so your air tool can run for longer before the air in the tanks drops below the air compressor pump cut-in pressure.
So this is also a great way to help reduce the stress on your air compressor – if it’s got a 50% Duty Cycle and it spends 5 minutes on and 2 minutes off – you’re over-stressing it!
Check out my guide to air compressor duty cycles for more info.
Considerations of Adding Another Air Receiver Tank
- Not ideal for continuous use of air tools (compressor will always be playing catch up)
- Great for intermittent use of air tools (compressor gets given a chance to cool)
- Cost-effective as only need to purchase another tank (not an entirely new compressor)
- Need to size the tank correctly even for intermittent use (find out how to size an air compressor tank here)
- Still need to check the duty cycle of the air compressors to size the air compressors correctly in relation to the air tool working CFM
It’s important to make sure your compressor is still operating within the limits of the duty cycle. Adding a tank to the system can actually decrease the working time vs idle time ratio, resulting in a reduction in the duty cycle even if the pump is actually running for longer.
This technique is a great way of reducing the load or how hard your compressor works, giving you the ability to allow it to operate at a lower duty cycle safely and whilst delivering the CFM requirements of your air tool.
This technique of increasing CFM can cause you to have to stop-start your work frequently if you are continuously drawing down air, that’s why this solution is better for stop-start or non-continuous applications as the compressor pump is given time to “catch up” with demand.
When the air receiver tanks drop below the cut-in pressure, the air compressor will require a greater amount of time to refill the tanks, as you now have a greater volume to refill than when you had just one tank.
This is a key consideration as the length of time the compressor runs, and the amount of time it spends idle (cooling down and not operating), have these duty cycle limits which are specified by your air compressors manufacturer. Operating a compressor outside its specified duty cycle runs the risk of causing permanent damage or even failure to the air compressor pump and motor.
Note, the bigger the tank, the longer the ‘periods of continuous’ use can be without the compressor essentially lagging behind demand. This ultimately leads to the system producing less than the required CFM.
The smaller the air receiver tank, the smaller the ‘periods of continuous use’ can be without the compressor ‘lagging behind’ demand.
An impact gun would be an example of a tool that sees short periods of continuous use in its typical use case.
On the other hand, a CNC machine or wet spraying gun might demand longer periods of use at their required CFM. This would either demand a huge air storage capacity using an underrated compressor or for you to actually increase the compressor pump delivery CFM capability.
Increasing the Size of the Existing Compressor Pump & Motor
Increasing the compressor pump can give you increased CFM which you can call upon continuously. Increasing the size of the motor won’t necessarily increase the CFM as the pump is typically designed to work with a specified motor size, so you essentially would end up with an oversized motor on a tiny pump.
Considerations of Increasing the Size of the Existing Compressor
Retrofitting a new compressor pump and motor to an existing tank may be marginally cost-effective depending on your tank size and age. In many cases, it may be more cost-effective to simply buy a new, higher CFM compressor complete with a tank suitable for your applications.
Please be vigilant in your research prior to making any changes to ensure that your air compressor is capable of them.
How to Increase CFM on Air Compressor
|Method||Difficulty (High/Mid/Low)||Do you require extra components?||Ideal for Continuous (C) or Intermittent (I) Use|
|Decreasing the Pressure to Increase CFM||Low||No||C|
|Adding Another Compressor of a Similar CFM||High||Yes||C & I|
|Connecting Two Compressors Together of Varying CFMs||High||Yes||I|
|Adding Another Air Receiver Tank||Med||Yes||C & I|
|Increasing the Size of the Existing Compressor Pump & Motor||Med||Yes||C & I|
FAQs (Frequently Asked Questions)
The higher the CFM of your air compressor, the more air it is able to deliver. Whether it is better or not depends on your application – if you’re operating heavy air tools like impacting wrenches or nailing guns then the higher the CFM the better, but if you’re using more general use tools, then that high CFM may not be necessary.
A good CFM depends on your tool requirements, typical air tools will only require 0-5 CFM from a small portable air compressor at 90 PSI. On the other hand, larger tools may require air compressors that exceed 10 CFM.
It will increase the amount of CFM available (as you have greater storage and therefore can work for longer periods) but it does not increase the air compressor’s pump CFM. To increase the CFM of the actual air compressor you would need to increase the pump/motor sizes!
To improve your air compressors performance you could:
1. Improve the quality of the air intake
2. Improve system design
3. Determine the correct pressure needed
4. Minimize pressure drop
5. Maintain your compressor
Reader’s Questions Answered: Increasing Air Compressor CFM
Question: Can you increase CFM on an air compressor? Or Increasing SCFM?
This writer wants to know how to increase the CFM of their air compressor as the output is not enough for spray painting purposes. (The writer actually wanted to know about how to increase SCFM on an air compressor, but the fact that what we’re actually talking about here is CFM is dealt with quickly in the response).
The question: I understand that the rate of SCFM depends on many factors (temp, humidity, etc). However, I am trying to drive a Car Paint gun that states an 8 SCFM rating. My compressor runs at 5.7 SCFM @ 40 PSI.
Now, I could buy a new compressor to increase that, but I don’t really do this task very much, and was curious if I could do any of the following to increase SCFM?
Run two compressors, borrow my neighbors and connect them to a T and drive a mainline out that would connect to the filters and the gun?
Or could I connect a 10 Gallon tank that is connected from my main compressor and connects to the spare tank? I would set the main compressor to 90PSI, and put a regulator on the spare tank for 40PSI which the gun calls for?
Or if I am not thinking right at all please let me know what might make the most cost-effective solution.
Thanks for your question. You say your paint gun states “8 SCFM” at 40 PSI.
Just FYI, to my mind and definition, compressed air isn’t SCFM, it’s CFM since I understand that SCFM refers to pre-compressor Standard Cubic Feet per Minute. But besides that…
Your present compressor will give you 5.7 CFM at 40 PSI. What pressure and flow will your neighbor’s compressor provide? Is it big enough to give you all the flow you need at the 40 PSI?
You can certainly run two compressors to the same reservoir. As you point out, you’ll need to adjust the cut-out and cut-in pressures of the two compressors to have them work properly.
Having an extra air reservoir that fills when the paint gun isn’t running will be helpful. It’s hard to say how long you can paint with the air from that reservoir before you empty it and your compressor supply pressure drops to cut in and the compressor has to run again to try and fill the tank.
Original Poster’s Response
Michael’s Response: Thanks a lot for the great information, you are right, I did not say that I can’t run the guns currently because I don’t have enough SCFM.
About putting the T in the system:
1.) Would I just use a common 1/4 NPT fitting and run both compressors to it?
1.a.) In regards to the pressure switches, that would be a concern only if I did this as a full-time thing, but I could just set both compressors to 90PSI and let them run when the air is low correct? I just need to paint parts of the car for about 1 – 3 hours tops before shutting down.
2.) Should I have an additional tank that receives the air from both tanks and then draws air from it? I would assume I could just punch a hole in the tank, thread the fitting and use a T to input air, then use a regulator to set the PSI out of the spare tank.
3.) Would it make any sense to punch a hole in my current compressor’s tank towards the bottom, and thread it for an NPT coupling through which another compressor would connect? This would fill the tank on top of the other compressor. I am not sure if threading new holes in the side of tanks are safe since the metal seams are thinner compared to the fittings that are in it from the factory.
Thanks again for all the help.
Anonymous Poster’s Response
Another visitor commented on Increase CFM:
Michael, your little compressor can not obviously compress air at the rate the paint gun can consume it. So how do you run your paint gun then?
You don’t mention it, but I’m thinking that you have a compressor that fills an accumulator tank, and that would be your available air supply. The volume of the tank is your CF (cubic Feet of storage). Depending on the size of the main tank, you will be able to use the paint gun at 5.7 SCFM until the tank was drawn down to the “cut-in” pressure (when the compressor would automatically turn on). At that point, you might as well take a break, let the compressor re-fill the tank and then rest (cool off and let the moisture condense).
By adding a second tank into the system, you have increased the system storage capacity (@ 90 psi), and will be able to run the paint gun for a longer interval. Put a regulator between the last air tank and the gun, and set at the tool pressure (40 psi). You will still face the same problem when the system capacity is drawn below what the compressor can produce.
I would definitely add a second tank, the larger the better. Just remember that it will take your compressor longer to fill the system, but more air volume will be available to your tools, and the compressor will not cycle as often.
If this doesn’t give you enough “paint time”, then borrow your good neighbor’s compressor and “TEE” it into the system. The combined SCFM outputs of the compressors will run the paint gun and fill up both tanks.
This is what I recently did in my shop when I added a second compressor (I posted it on this site). Because the compressors were not identical in size and HP, the pressure switches had to be replaced with adjustable ones, so that they both came on and off at the same time. In your case, as this is not an everyday project, you can manually play with the compressors to get them going at the same time.
I hope that this helped you.
I want to increase my compressor pressure from 145 psi to 200 psi?
I want to increase my compressor pressure from 145psi to 200psi 60hp – 238cfm – 145psi
Rajesh, if the air compressor is not built to produce 200 PSI, then it won’t do it. If you try to adjust the cut-out pressure to a higher level, you are at risk of damaging the compressor, or possibly yourself, if the components in the compressor air circuit are not built for that pressure.
Check the specs on your air compressor to see what pressure it is rated for. If that pressure is not high enough for your needs, you need another air compressor!
How to Increase CFM on Air Compressor?
I’ve got a small 1.5HP, 6 gals, 2.5 CFM pancake Husky air compressor. That’s below the specs for most nailers. Could adding another 5-gal tank almost double its CFM?
Nope, adding another tank will just give you that much more pre-compressed air, and that means that you will be able to nail longer before having to stop and wait for the compressor to catch up.
It also means that it will take longer for the compressor to come back up to cut out the pressure level.
You can’t increase CFM from a compressor without increasing the motor and/or the pump size.
What you can do is dial down the pressure on your regulator to the lowest pressure level your tool will work at. This will make your air charge last longer before the compressor has to restart to bring the pressure back up.
How Do I Get More Pressure to Fill Truck Tire to 120 PSI?
I have recently purchased a new compressor.
Twin-piston, oil base. It is supposed to develop 125psi at max.
I am typing to fill truck tires that require 120psi, but it won’t go past 80 psi. The output gauge is set to 110 psi, and won’t go any higher. The tank gauge is showing 130psi, so in theory, I should be able to get these tires inflated to at least 110psi. Why can’t I get more than 80psi in these tires?
Larry, “It is supposed to develop 125psi at max.”, in my opinion, the output figures of air compressor suppliers are similar to those of the mileage claims for the car manufacturers. It just ain’t so!
You are, with your reputed 125 PSI compressor output, trying to fill a tire that needs 120 PSI. It may not be possible. Not only are you pushing the envelope for the air compressor (like driving your car with the pedal to the floor all the time) but you may also have issues with the accuracy of your air gauges. The cheapo kind installed on low-cost air compressors might have an accuracy of +/- 2-5 PSI from what you see on the gauge.
Now, you say that the “Output gauge is set to 110 psi,” and won’t go higher. I take this to mean that your air regulator is set for 110 PSI, and regardless of how you try to adjust it, you can’t get the gauge reading to go up past 110 PSI, even though the tank gauge shows 130 PSI?
That is strange. First, your air compressor is rated for 125 PSI, and you are seeing 130 PSI on the tank gauge. That may be the gauge inaccuracy I wrote about earlier, yet it does speak well that your air compressor can deliver the output it promises.
Do you have an airline to your tire chuck? Try this. Put a connection on an air gauge, and plug that air gauge into the airline. If it, too, sees 110 PSI, then that is all your regulator is allowing through, and that may mean a bum regulator, if it is, indeed, rated for handling up to 130+ PSI.
Perhaps you might post a comment here with the results?
How to Get More CFM Out of Air Compressor?
I currently have a compressor with a 3.2HP motor running at 1040 rpm producing 11.2 CFM @ 90psi. If I install a 5HP motor running @ 3240 rpm will it produce more CFM? If so what would be the max rpm I could do?
Howdy Mack. Nice to hear from you.
If the mechanical ability of your compressor can handle the higher RPM, then yes, in theory, you could get more CFM out of it.
However, I’d be willing to bet that by up-sizing the motor, you’ll destroy the compressor mechanically in fairly short order. They are designed and built to handle the motor that comes with them.
Good luck with your experiment.
2 Compressors – Plumb Them Together to Increase Flow?
This sounds simple, but you know how that goes. If I want 12ish CFM can I just use (2) 6ish CFM compressors and some kind of Y connector to supply a sandblaster?
Victor, having two compressors supplying your application will increase the available flow, but whether or not you will get a true 12ish CFM or not remains to be seen.
If it were me I would have the two compressors feeding into one tank using the “Y” you spoke of, but upstream from the “Y” in the line from each compressor, you would need to put a one-way valve so that air can only flow downstream to the tank, and not back into the adjoining compressor tank.
Then I would plumb the line from the tank to my sandblaster or other air tools. Visit our connecting two air compressors together guide!
DIY High CFM Air Compressor?
I have 2 extra compressors sitting in a corner of my garage, and I want to get more CFM…
My current compressor is a 3 HP, 18 gal.
I want to run about 8 CFM @40 psi
Do I still need to check valves if I have output regulators on all 3 compressors set to the same psi, tee’d up, then run through my 3/4 NPT filter-regulator-oiler, and use the regulator on that to control working pressure? I use about 30 feet of 3/8 air hose on a reel…
If it works, I plan to put valves on all 3 so I can just run 1 or 2 and not have it charging all 3.
I am restoring old snowblowers, and find that I use air a lot.
Another issue is that I have had couplers freeze up in the winter, is there anything I can do to prevent this, I.E., put an ice-melting fluid in the oiler?
Joe… what, you have cold weather in Minnesota? Who’d have thought? 🙂
Bone dry air won’t freeze couplers, valves, cylinders, or air tools.
Some folks run anti-freeze through the airlines using an in-line lubricator. Not my thing.
Read the pages on air preparation or air treatment for solutions to drying air so that there is no water in the compressed air stream to freeze.
As to the airflow question, why not read our articles on how to add a second tank to air compressor and connecting two air compressors. I hope I have explained the process fully. If, after reading, I’ve left any holes in info, post a comment here with the question.
Is It Possible to Create a Higher CFM Rating on an Air Compressor?
I have an air compressor with a rating of 4.1 CFM @ 90 PSI. I need an air compressor at 5.4 CFM @ 90 PSI. Is there a way that I can make this compressor give me the CRM that I need or should I go buy a new compressor?
The output of an air compressor is predicated on the pump size and the motor capacity. The designers balance these two and then take into account the most important factor… cost.
So, they decided that they would build an air compressor with 4.1 CFM @ 90 PSI to fit their particular niche and cost formula.
You could tamper with the pressure switch settings to increase the cut-out pressure level. You could, also, destroy the compressor motor by overloading it in so doing.
Sorry, Jay, you need to really think about how much air you need for now and the future, and then get a new air compressor with even more capacity than that. Folks almost always used more compressed air capacity than they have.
How to Increase CFM of Air Compressor?
I have an Atlas Copco screw air compressor with a rated capacity of 500 CFM at 7.5 bar and 400 CFM at 10 bar.
I currently running the compressor at 10 bar, can I increase the flow from 400 CFM to 500 CFM by decreasing pressure to 7.5 psi? I have tried regulating the pressure switches. But there is no change in CFM. I need to know how can I increase the CFM of my compressor.
Unless you want to get into the physics side of it to understand why, and I don’t, it’s simpler for me just to understand that the higher the pressure output from a compressor, the lower the flow.
Your compressor is rated for 400 CFM at 7.5 bar you say, yet you are running it at 10 bar.
So, if you turn down the output pressure regulator to 7.5 bar from 10, your flow volume should increase to 400 CFM as per the specs, if the compressor is running at efficiency.
In theory, and maybe practically too, if you don’t need air at 7.5 bar, turn the regulator down a little lower, and that should give you even more airflow at that lower setting… up to the maximum capacity of the compressor at that pressure, whatever that may be.
…is determined by the pump (screw) and the HP into it. So, the only way to increase the flow is to increase the power input. You can’t do that.
However, I’m driven to ask why you want to do this – depending on your needs, a storage tank may get you what you need if you don’t require a *continuous* flow at a higher rate.
Exactly what Bill says
What you need to find out is what tools/machines are you running. Do they actually need 10 bars or even 7.5 Bars?
If you’re only using air tools then I’m sure you can turn it down but if you’re using CNC machines for example and they need the 10 Bar then you may need to ask yourself whether your compressor is powerful enough to cope.
What is your compressor’s power rated at, 5.5 kW? 7.5kW? More?
Let us know.
If you have any questions regarding the best ways to increase air compressor CFM, please leave a comment below, with a photo if applicable, so that someone can help you!
My compressor have a 304 psi pressure at 530 CFM i want to increase CFM upto 900 my work is continuing
I am a bit concerned/confused by most stating the CFMs of their compressors. Most compressors list their flow rates at specific pressures in SCFMs not CFMs. When converting from SCFM to CFM, the CFM is usually quite a bit lower than SCFM. So, for example, a compressor rated at 8 SCFM at 40 PSI may actually be closer to 4-5 CFM at 40 psi. I am just hoping that those on this site recognize that SCFM does not equal CFM and that when converting between the two, CFM will be substantially lower than the cited SCFM.
CFM is CFM. but CFM at different temperatures and humidity does vary.
SCFM is simply CFM at a SPECIFIC temperature and humidity.
I’d like a cite for your example.
CFM (out) also varies with PSI and not just Temp, humidity and atmospheres. My compressor indicates an SCFM of 8.0 at 40 PSI and an SCFM of 5.7 at 90 PSI. Based upon the cut in and cut off pressures and time in between, I calculated the maximum compressor CFM to be 5.2 ( average based upon 5 trials). The CFM listed on the compressor is 11.5 but I assume this was calculated based upon piston displacement. So the question is how do I calculate CFM (out) at the output pressure. P(1)V(1) = P(2)V(@) is a static measurement and does not apply. There are a… Read more »
Ah, I see.
Yes, that difference is due to the increased valve blowby pressure. The time between the valve(s) closing and when it would ideally be closed. You can’t accurately predict that. The designer might be able to, but not a user. And any chart might or might not be ballpark for your particular compressor, even the same model.
So, the only way to know if it’ll work is try it.
Not enough air? Maybe a bigger compressor, or receiver, or just a second compressor in parallel, depending on if you can wait for the compressor to “catch up”.
Thanks Doug. I have indeed got a hold of a used compressor that is a duplicate of the one I have. So At 40 PSI each compressor will put out 8 SCFM and each is attached to 15 gal (2 cubic feet) tank. Hopefully that will be enough to keep my gun spraying given that I do not want to drastically exceed the duty cycle i. e. 50%. Thanks again for your input.
Just keep an eye on PSI gauges, too much pressure is a problem, as well as too little…pressure is to mechanical systems what voltage is to electrical/electronics (in fact voltage is referred to as the “push” or pressure causing current flow). Too much of anything is not a good thing, nor too little.