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Worthwhile Compressor Upgrade?

Quaraxkad

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I have an old-ish DeVilbiss air compressor. It's 20 gallons, 8.3SCFM@40psi, 5.8SCFM@90psi, 125psi max. It needs a new regulator, and I'm wondering if it'll be worth it to upgrade a few other things as well... If I'm measuring correctly, all the piping is 1/4" (calipers measure the pipe OD as just a tad over 1/2"). If I were to swap out the 1/4" pipes for 3/8" or 1/2", would that be at all beneficial? The outlet on the tank itself will still be 1/4" but with a reducer pipe to hook up to a 3/8" or 1/2" tee, and I'd be able to use a larger more free-flowing regulator and fittings. Does that make sense, or should I not even bother?

Some pictures for reference...

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bigsteve2011

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Upgrading the pump is the best way to improve the CFM of the compressor.
If you were to spend the time changing the pipe sizing from 1/4" to 3/8" then it should be 3/8" throughout, so having the reducer at the regulator would counter act the improvements made with the 3/8" pipe.

I haven't done any improvements to mine other than changing oil, air filter, replaced petcock valve with a ball valve to make draining it better, and adding some rubber feet to the bottom so that it doesn't vibrate as much.

Hopefully someone else will chime in with some real world results or advice.
 

Charles (in GA)

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Put a new regulator on it and drive on. Anything you are suggesting will not help the situation one bit. Most I would consider is a good ball valve between the T and the regulator. That way, you won't have to mess with the regulator and the tank will hold air between uses.
 

CNGsaves

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^ ^ ^ +1 for above. No need to mess with parts that are working fine and not leaking. Add the ball valve to hold air in tank.

Also, install extension pieces underneath tank to make it real easy to drain out water. Rust in those horizontal tanks is biggest risk you have . . . . brought on by not draining the tank. Get in habit of draining daily.
 

pancho400cid

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Ditto all the above. You would not see the slightest increase in performance by increasing the piping between the pump and tank or between the tank and regulator.
 
OP
Q

Quaraxkad

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If you were to spend the time changing the pipe sizing from 1/4" to 3/8" then it should be 3/8" throughout, so having the reducer at the regulator would counter act the improvements made with the 3/8" pipe.

I would only have reducers between the tank and the T and the T to the pressure switch. So I'd be able to use a larger regulator. Obviously it would still be "choked" by the 1/4" pipe coming out of the tank, but wouldn't it still flow better *after* that?


The reason I thought about this to begin with is that I have an old impact wrench, also a DeVilbiss, it was probably purchased at the same time as the tank. It's not a particularly powerful model, but I've really never been able to get it to break anything free. But before buying all new air tools I wanted to make sure it's at least getting all the air it needs, I figured I'd start by removing as many restrictions as possible starting at the tank going all the way up to the tool. And if I end up needing new tools anyway, better airflow would only make those tools that much more effective.

As for the pump, I wasn't considering replacing that because I don't often use air tools so frequently that the motor has to run consistently, so I figured I'm OK there. If I ever wanted to replace that then I would replace the entire compressor since the tank does have some rust on the exterior bottom already. The SCFM from this pump is suitable, but then I figured what really matters for short "bursts" of usage is how much air the tank (rather than the pump) can let out, and that's limited only by the fittings and hoses. The hose is 3/8" Goodyear but it's longer than I need so I'll get a shorter one, maybe larger diameter as well. I'm not sure what size the fittings are (or how to measure them), I figured I'd try 3/8" automotive fittings (Legacy Type G ones look pretty nice).

But... You all think that the 1/4" lines and fittings are good enough, that larger piping won't give me any benefit? If that's the case I'll just replace the leaky regulator with another 1/4" one.
 

scw1991

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A 15.0 amp motor on 120v/1ph circuit equates to just a tad over a "true" 1HP rating. As other have stated, replace the regulator and be done with it.
 
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redmondjp

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do you need more air?? Maybe it's time for different kind of upgrade then your thinking... new compressor.
+1 Even if it was a 30 gallon 2HP twin-piston single-phase portable compressor, it would perform better and be more durable than this unit. You can find those pretty regularly in my area used for $125-150.

The only modification that I would make to this unit, for maximum air tool performance, is to directly connect to the tank (NO regulator at all in the air circuit - no reason for it with a single-stage compressor) with the hose, and one high-flow quick-connect right at the air tool. That will give the best performance, even if only for a few seconds at a time.

How, you ask? Remove check valve from tank. Install close ****** and black iron pipe tee sideways in that port (so straight shot through tee is vertical). Reinstall check valve on top of the tee (may have to shorten or bend output pipe from pump). Route air hose out of side of tee using a thread reducer.

Also, make sure to check oil level in your compressor - if it goes low, compressor pump life gets very short! I recently borrowed my neighbor's Dewalt portable compressor to re-roof a garage. After use, I checked the pump oil - oh shoot, there was almost none in there! I drained out what was left and bought him some new oil.
 
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bigsteve2011

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I would only have reducers between the tank and the T and the T to the pressure switch. So I'd be able to use a larger regulator. Obviously it would still be "choked" by the 1/4" pipe coming out of the tank, but wouldn't it still flow better *after* that?

The pump is still what determines how much flow is in the lines. The more air it pumps the more air coming out of the hose.

Like someone else said the cheapest option is to just replace the regulator and be done with it.
 
OP
Q

Quaraxkad

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Alright, so I'm just going to replace the regulator, hoping I can find one that flows in the right direction without having to mount it upside down or use a trail of pipes and elbows!

But there's one more thing I want to confirm... I sort of mentioned it in passing above but I've seen it contradicted so many times, so please tell me if any of this is wrong... About the SCFM ratings. Just for discussion, we'll ignore the over-ratings of compressors and under-ratings of tools. I know that the ratings are based on what the *pump* is capable of. My pump is rated at 5.8SCFM @ 90psi. This is how fast the pump can refill the tank, not strictly how much it can provide to my tool. So for light-duty cycle usage it's essentially meaningless. Now assuming that the tank is full and at its max pressure, if I use a tool at 90psi, until the pressure drops below that and pump cycles on, that rating means absolutely nothing to my tool. And then once it does turn on, that rating tells me whether it will be able to refill the tank to maintain pressure while the tool is simultaneously under constant use. So if I'm just breaking loose a single bolt with an impact at 90psi, it doesn't matter what the pump SCFM is because it's not part of the equation. Is this not correct? I should be getting a whole lot more than 5.8SCFM at the tool, so theoretically couldn't I just as easily use a tool that's rated for 10CFM, at least until the pressure in the tank drops below 90psi? And when it does, just wait for a minute until the tank is re-pressurized and start again.

This is what I based the idea of upgrading the lines off of, obviously it won't increase my "SCFM" ratings, but I assumed it would remove restrictions between the tank and the tool and that's the only thing that matters in my light duty cycle scenarios. Add to that all of the threads I've seen when searching around on this forum about you guys installing lines through your garage, and always recommending larger pipes and larger fittings, etc...

I will eventually buy a whole new compressor, but I won't be buying a cheapy and therefore it will have to wait until I can afford a nice one or I find a good used one locally.
 

sberry

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That choke in the line is pretty short and the ID of a 1/4 pipe is close to a 3/8 hose.
HF, maybe even Walmart sell a reg cost about 10$ for that, Lowes maybe a pinch more, good comp to keep it cheap although a guy can re use a reg. A short hose will help most.
 
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sberry

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will eventually buy a whole new compressor, but I won't be buying a cheapy and therefore it will have to wait until I can afford a nice one or I find a good used one locally.
There are a couple cheap models that are super good and for the price to plug and play a good long while with most outlasting the owners.
One of those Puma is about 400$, modest motor starting load. If something else fell in to my lap I would be all for it. They are not for ******** rebuilding but I got a hobby farmer bud got a cman right out of the box for about that same money on sale, done all he asked. A comp and 50 ft of 3/8 hose. It replaced one just like the OP of this thread, some too small little sucker tripping a breaker.
 

redmondjp

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Alright, so I'm just going to replace the regulator, hoping I can find one that flows in the right direction without having to mount it upside down or use a trail of pipes and elbows!

But there's one more thing I want to confirm... I sort of mentioned it in passing above but I've seen it contradicted so many times, so please tell me if any of this is wrong... About the SCFM ratings. Just for discussion, we'll ignore the over-ratings of compressors and under-ratings of tools. I know that the ratings are based on what the *pump* is capable of. My pump is rated at 5.8SCFM @ 90psi. This is how fast the pump can refill the tank, not strictly how much it can provide to my tool. So for light-duty cycle usage it's essentially meaningless. Now assuming that the tank is full and at its max pressure, if I use a tool at 90psi, until the pressure drops below that and pump cycles on, that rating means absolutely nothing to my tool. And then once it does turn on, that rating tells me whether it will be able to refill the tank to maintain pressure while the tool is simultaneously under constant use. So if I'm just breaking loose a single bolt with an impact at 90psi, it doesn't matter what the pump SCFM is because it's not part of the equation. Is this not correct? I should be getting a whole lot more than 5.8SCFM at the tool, so theoretically couldn't I just as easily use a tool that's rated for 10CFM, at least until the pressure in the tank drops below 90psi? And when it does, just wait for a minute until the tank is re-pressurized and start again.

This is what I based the idea of upgrading the lines off of, obviously it won't increase my "SCFM" ratings, but I assumed it would remove restrictions between the tank and the tool and that's the only thing that matters in my light duty cycle scenarios. Add to that all of the threads I've seen when searching around on this forum about you guys installing lines through your garage, and always recommending larger pipes and larger fittings, etc...

I will eventually buy a whole new compressor, but I won't be buying a cheapy and therefore it will have to wait until I can afford a nice one or I find a good used one locally.

See my first post above - doing that modification will give you the maximum performance for operating your impact gun with that compressor, and it will only cost $10 worth of pipe fittings. You don't need or want a regulator for that tool anyways. The air in your tank will give you a short burst of additional flow and you want the lowest restriction for that momentary burst to achieve maximum pressure/flow at your tool, even for just a few seconds. This will give you more nut-busting torque.

The other side of that equation is a quality impact tool - there are many recent threads on this topic on here. It makes a huge difference! For example, check out the NitroCat which seems to have a good bang for the buck.

Here's the truth: the numbers on your compressor are LIES. You do not have a true 5HP (running HP) motor. It can achieve 5HP for 0.36 seconds, after which the magic smoke comes out. And the flow rating is suspect as well. Combine that with low-quality air tools that consume twice the airflow that is claimed on the box, and you have the perfect storm of air tool underperformance and user disappointment (with a chorus of rusty lug nuts singing "Neiner neiner neiner, you - can't - get - us!").
 
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sberry

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It might help a little for an air gun if it matters. More than any other factor including a fitting change will be air hose length and size. It doesn't have the top end to start with and that 125 is going to disappear in a split second, wanna make it work the best, put 5 ft hose on and drag it around to each wheel.
A little 14 pipe fitting doesn't hurt much but the difference between a 1/4 and a 3/8 hose is huge and the difference between 25 and 50 ft is a leap.
They would have made the fittings bigger if it would have worked better.
 
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FunkyfullWidth

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I had a little cambel hausfeld compressor like that a while back. I used the hell out of it and it ended up not being enough. I went out and bought a craftsman 33 gallon and while it was better in some respects it was worse in others. I made the jump to a 60 gallon 220v speedaire that i found locally for 200 bucks. Even that isn't enough sometimes.

My point, if you find yourself needing air more frequently. Instead of dicking around just go big. It'll save you money and time. Nothing beats a good compressor. Air when you need it, air when you don't need it. No more waiting for the thing to recharge while you cut a little piece of metal or while filling up a few super swampers.

The amount of difference your talking by doing your upgrades would be negligible at best. It's such a short section that it wouldn't really affect anything. I've noticed that using a good quality hose makes a difference. But it all boils down to what your using your air for. Albeit an impact, a grinder, a sand blaster, or just filling tires.
 

Charles (in GA)

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Alright, so I'm just going to replace the regulator, hoping I can find one that flows in the right direction without having to mount it upside down or use a trail of pipes and elbows!

Regulators have and in and out, and usually two ports for a gauge. There is no way you will get a regulator that you cannot fit to the compressor. A ball valve might be a little tricky, but I'd put one in. Take out the regulator and ****** back to the T. Install a close ******, a ball valve, another close ******, and the regulator. It might be longer, but not by much. Quite frankly, at 125 psi max, I would probably eliminate the regulator alltogether, unless you have some serious need to regulate such as painting. Then have a regulator with ****** and coupling you can plug in.

But there's one more thing I want to confirm... I sort of mentioned it in passing above but I've seen it contradicted so many times, so please tell me if any of this is wrong... About the SCFM ratings. Just for discussion, we'll ignore the over-ratings of compressors and under-ratings of tools. I know that the ratings are based on what the *pump* is capable of. My pump is rated at 5.8SCFM @ 90psi. This is how fast the pump can refill the tank, not strictly how much it can provide to my tool. So for light-duty cycle usage it's essentially meaningless. Now assuming that the tank is full and at its max pressure, if I use a tool at 90psi, until the pressure drops below that and pump cycles on, that rating means absolutely nothing to my tool. And then once it does turn on, that rating tells me whether it will be able to refill the tank to maintain pressure while the tool is simultaneously under constant use. So if I'm just breaking loose a single bolt with an impact at 90psi, it doesn't matter what the pump SCFM is because it's not part of the equation. Is this not correct? I should be getting a whole lot more than 5.8SCFM at the tool, so theoretically couldn't I just as easily use a tool that's rated for 10CFM, at least until the pressure in the tank drops below 90psi? And when it does, just wait for a minute until the tank is re-pressurized and start again.

Your thinking is correct, the flow is what the tank can supply, up to the point the tank runs out or low, then its up to the pump. I used an impact for years on a 12 gal/ 1 hp Craftsman 1970 vintage compressor. I mean from about '70 or '71 up to about '92 or so when I got a slightly larger compressor, and finally my 80 gal/2 stage/7½ hp. I still have that little Craftsman. When you start to use a sander, drill or grinder, they use air so fast, you get nothing done however. Impacts yes, air hammers yes, but stuff that spins fast and long no.

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This is what I based the idea of upgrading the lines off of, obviously it won't increase my "SCFM" ratings, but I assumed it would remove restrictions between the tank and the tool and that's the only thing that matters in my light duty cycle scenarios. Add to that all of the threads I've seen when searching around on this forum about you guys installing lines through your garage, and always recommending larger pipes and larger fittings, etc...

Restrictions such as a ¼ pipe are not enough on a compressor to be an issue, given their short length. If that ¼ pipe was 50 ft long, you would have so much friction loss in the line to be a problem, but just a few inches really does not choke it down enough to be an issue. Look at the tiny holes in the sleeve inside an air coupling that you are pushing air thru to the tool, or the air tool ******, short distance is not a real issue so long as its not a tiny orifice in comparison to the flow of the tool.

I will eventually buy a whole new compressor, but I won't be buying a cheapy and therefore it will have to wait until I can afford a nice one or I find a good used one locally.

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