Impeller Upgrade: Analyzing CFM Changes on Harbor Freight Dust Collector

In this video, we delve deep into the efficiency and performance of the Harbor Freight Dust Collector with a WEN Impeller upgrade. We test each stage of the improvement so we make sure we know what kind of performance our dust collector can provide.
CFM Calculator: www.engineerin...
Wen Impeller: wenproducts.co...
Anemometer: amzn.to/3PElQrw
Replacement Harbor Freight Bags: amzn.to/3LGzBF9

[@stevereese6488]

Little physics here, for every turn or bend you have in a hose there is a calculated percentage drop in cfm. Also your effective vacuum flow at the end of the hose is the radius length away from whatever you are drawing extraction from. So if you have a 5” hose then at 2.5” away from end of hose you will loose suction at what it is at the hose. That’s why some dust boots are ineffective. I’m retired from nuclear power in the radiation protection nuclear physics department. When we would use Hepa units to draw potentially loose surface contamination away from a worker from a component they are working on, we calculated what size(cfm) unit to use based on hose run routing and length. Minimum hose we ran was 6” to a 500 cfm unit. We also had units up to 2000 cfm but they were huge and ran off of 3 phase 220 volts. We always had to use a power splitter or sometimes the motor ran backwards lol fun stuff with 3 phase. The only other upgrade is better cyclonic action in the separator, adding an actual filter, and inline booster fan in line in front of the system.

[@traviscopeland4151]

Forward-curved impeller blades produce lower pressures and higher flows (more cfm) while backward-curved impeller blades produce more pressure and lower flow. You're seeing higher cfm rates because of the ~2" increase in impeller size, but also an increase in discharge pressure (and thus suction vacuum) because of the reversal of the blade orientation. A quick search on different impeller designs will give you a ton of info about this from people far more qualified than me 🙂

[@lindseyacresfarm]

Thanks, for the info. I will definitely look that up.

[@gustaveliasson5395]

PSA: The reason why the fins on the original impeller were facing the "wrong" way is because when manufacturers rate their blowers, they test the blowers without *any* filters or hoses attached; they just take the blower (motor, housing, impeller), and test the performance of that unit by itself. And when you've got just the blower sitting by itself, the original impeller will move more air than an equally-sized impeller that's "properly" designed (like the aftermarket one that Lindsey retrofitted to his blower). So the manufacturers test it like that, and then slap a label on it saying "Look, under *ideal* circumstances, this unit will move *THIS* much air". They do this while quietly "forgetting" that in the real world, there *ARE* going to be a bunch of filters and tubing and hoses attached, not to mention that before the air even reaches those, it'll first have to pass through the internals of a tablesaw, or a planer, or a thicknesser, or a planer-thicknesser combo or drum sander or whatever machine tool is attached at the end of all that plumbing. Maybe you've at some point heard some old story about how in the USSR, products were... just a little bit shit, for lack of a better term, because the management were tunnel-visioning in on certain design requirements set by the state, to the detriment of the actual *usefulness* of the product to the end user. Well, sometimes that happens here too. In the case of dust collectors, it's CFM. Everybody wants CFM. The manufacturers *know* that everybody wants CFM. So they give you CFM. Even when it means that you end up with a piece of equipment that is... just a little bit shit, for lack of a better term, under real-world conditions, and that you have to retrofit with aftermarket parts right out of the box in order to make them genuinely useful. Obviously, it's not a U.S.-specific thing, either. I'm swedish, and when I browsed the retailers that sell here, I hardly saw anybody list the pressure ratings of their blowers. Metabo did, for their SPA 1200 (0.55kw or ~¾hp, with a 1600 Pascal peak pressure,) and SPA 1702 W (0.75kw or ~1hp, with a 1730 Pa peak), but apart from Metabo, everyone is giving us dust collector performance metrics in terms of m³/min and that's it. P.S. Please pin this. P.P.S. The forward-swept fins of the original impeller are also less energy-efficient than the backwards-swept fins of the replacement part, *but* therein lies a tradeoff for the manufacturer; the back-swept impeller would need to be *larger* in order to move the same amount of air. So what do you go for? * A smaller (and therefore cheaper) impeller in a correspondingly small and cheap housing? * Or a larger (and therefore more expensive) impeller in a correspondingly larger and more expensive housing, that moves the same amount of air as the smaller one, but using less power to do so? Obviously the up-front cost of the larger impeller and housing outweighs the lifetime energy waste of the more compact counterpart, and so that's another incentive to enshittify the product.

[@ironchefboyardeee]

It'd be interesting to see the similar tests but measuring amperage and power. Also testing out a pleated filter from Wynn would be interesting to see how minimal the CFM drop can be.

[@richwigginton5553]

Just a note for everyone. If you have a 25' hose and you keep all the hose curled up next to the collector you are still pulling air 25'. The air must flow through the full 25' of hose regardless of it being stretched out or curled up.

[@lindseyacresfarm]

This for sure. Also to add the ribbed nature of the hose I had will also restrict airflow as well. If you can get as smooth of a hose as possible it is best.

[@moonolyth]

Great find on the fan blade, must upgrade!! The best takeaway I can give is to run the shortest flex hoses You possibly. No sharp turns. And any guards you have ... upgrade them the best you can, It is always best to collect dust where it is made !!!!! Mine works great but using 4in PVC. I also run the air to the outside rather than spending the cash on filters though it does get cold in the Georgia winters. Lastly, Band saws are low RPMs, and table saws, chop saws are high RPMs so keep high RPM machines closest to your vacuum system. The very best filters are two doors and a fan!

[@chrisdzisiak7540]

Fans are designed for a particular load, fan blades can straight, curved with the flow or curved against the flow. The pressure range that they are designed to work in is the basis for the fan curve design. They are designed for a particular load

[@markhoward3851]

I would love to see a comparison of the HF with the fan blades reversed. I'm still wondering if their scoop design could be more efficient if it was centrifugal like the 12" upgrade impeller.

[@Ashevillein]

Uh, 7 blades on both

[@sittingindetroit9204]

Has anyone removed the impeller guard at the y connector? This unit works great for everything but my planer. The longer slivers from the planer wrap around the "arms" of the guard and constantly clog the hose. As long as I don't suck up a screwdriver I don't think there is much risk. Downside I would guess is being "forced" to do an impeller upgrade if I damage the current one.

[@gustaveliasson5395]

4:31 Water at least has surface tension to hold it together somewhat, but air has *no* tensile strength at all; it's not a "pullable" substance. "Suction" in an everyday mechanical context, is just stuff being *pushed* from somewhere with pressure, to somewhere with *less* pressure. The ambient atmospheric pressure is what's *pushing* air into the shop-vac, same as it's pushing air towards the inlet of the dust collector. These systems are basically centrifuges that use impellers to spin air really fast in a circle until the air's own inertia causes it to "fall" out of the impeller, prompting the atmospheric pressure to continuously shove more air in trough the inlet.

[@C-M-E]

You've gotten that 99.5% correct, which is a win of itself. The impeller is creating a low pressure area (lower than atmospheric) in which the force people tend to attribute 'suction' is higher atmospheric pressure rushing in towards the area of low pressure. The more efficiently you can create said low pressure area for a given volume, the more air you can move. This is true of all air-moving systems from fans to jet engines. Shop vacs can pull a lower pressure but not higher volume, where dust collectors are exactly the opposite. Give each device the same power, internal working air volume and equal hose, you'd not see a difference other than the noise one produces over the other.

[@zadedmon206]

Looking forward to difference results at the tool venting outside vs though the bag filter. Great vid and thanks for doing the testing work for us!!!

[@lindseyacresfarm]

Not a problem. I am looking forward to giving it a shot. Based on how long my current projects are going, and taking forever. It will be early next year, but I need to do it as I'll be doing a larger project and putting it through its paces.

[@thedevilinthecircuit1414]

Seven fins. WOOT!

[@lindseyacresfarm]

Didn’t actually count them. I wonder how much of and effect it has 🤔

[@gustaveliasson5395]

?

[@briandolhun1968]

You mentioned that you were going to take the readings of your system with it venting outside in a future video....but I can't find it in your videos. I'm contemplating increasing the size or the horsepower of my dust collection system in my shop and wanted to know if it's easier or better to vent outside because I live in the country I can do this. But I need your help to know if the readings increased or if it's better to have cyclone? Thank you very much for your help

[@lindseyacresfarm]

Sorry, I haven’t been able to do it yet. I am hoping in March I can right before I start a remodel of a part of my house.

[@andremalenfant2900]

Use rigid pipes up to the tool and you will see an big improvement

[@lindseyacresfarm]

Thanks. That is my eventual plan. Though it might be a while since I keep tweaking my shop, heh.

[@natemartinez4595]

​@@lindseyacresfarmmy shop is also ever-evolving

[@DanielWorthen]

This is a long shot but I'm looking for some help. I run a dried food product through a hammermill and I need to serparate the flakes and the powder for sale. I am getting some of the powder by having a dust collector hooked up t oa closed box. The vent is on the top portion of the box so it collects the dust that is in the air. however, a lot of the flakes and powder are mixing together. Does anyone know of a good method to collect more powder?

[@tubewatcher8330]

Try cutting off the 5" hole and add a 6" or make a new input plate with a 6" hole.

[@lindseyacresfarm]

That is a great idea. I had thought about getting the super dust deputy that has a 6” hole, but it seemed wasteful since it just goes down to 5. In reality I could do the resize and do a main trunk line off of that. Hrmmm I need to think on this.

[@philippeterson9512]

That Wen impeller is backwards from the HF impeller. I’m thinking that’s not right.

[@lindseyacresfarm]

It is backwards. It is more effective, but i'd bet if the wings were the right way it would be even better. Unfortunately I don't have the fab skills to try to make my own impeller, otherwise i'd like to try.

[@jeremiahharris5002]

@@lindseyacresfarmyou can change the rotation of the motor by re wiring L1and L2 properly to the correct post. This can change the direction of current and allow the motor to turn the other direction.

[@gustaveliasson5395]

​@@jeremiahharris5002 No. Nonononono. You do *NOT* want to spin the impeller so that it's trying to "scoop" air in towards its center; you want the blades to be oriented to "shove" or "smear" air *away* from the center, i.e. the way the new impeller in the video is designed. If you try to scoop the air in towards the center, centripetal acelleration will still cause it to flow outwards (so there's no way to turn a centripetal blower's inlet into an outlet), and if there's absolutely *NO* restrictions to the airflow, you could get more CFM, but with almost no static pressure. So in a system with restrictions such as filters, inertial filters (i.e. dust centrifuges or "cyclones"), dozens of feet of tubing and hoses, and a bunch of machine tools at the far end, you *DO*, in fact, want an impeller like the new one Lindsey installed.

[@jeremiahharris5002]

@@gustaveliasson5395 I see what you are saying and what you are talking about does happen but only to blower housing built to be as discharged behind the fan or on all sides of the fan. This fan housing is a side discharge and the rotating of the fan and the scoops of the blades must be oriented in the same flow of circulation. Now, I will admit that if the fan were to spin it would create much more back pressure because a larger fan moving more air through a smaller size discharge will do that. So I do also believe you will increase CFM more and also increase WC if the discharge were increase larger than the intake. Fans displace more air when there is more resistance against the fan blades and less resistance in the housing. That is why I can see your point. A bigger fan does move more air simply because it is bigger but doesn’t create as much resistance for the motor to turn and keeps the motor from working as hard. As someone who works in the field of exhaust and ventilation, I am aware what this upgrade is doing and what it is not doing. And I can see your points clearly. This doesn’t change the fact that more air can be created by a fan which spins the proper direction with the discharge of the housing it sits in and the back pressure can be reduced by increasing the discharge outlet to its max.

[@kurtbilinski1723]

@@jeremiahharris5002 That only works if it's running on 3-phase power.

[@ladymoc1]

So I changed my impeller and I have it all the way up past the shaft end and the fins are flush with the opining. It touches the cover. Did you have any trouble with this issue.

[@lindseyacresfarm]

I didn't have that issue, but I did have hard time getting it back on. I took it off and IIRC I put the impeller back on then hammered the key into they key way. I don't quite remember.

[@paynetyler4173]

I have that unit so I'm eager to see more experiments and variations. I have a pleated filter but I'm thinking of blowing the fines outdoors instead. Could you compare the cfm/pressure between spiral flex hose and a straight run of the same length and (purported) diameter?

[@lindseyacresfarm]

I am not sure I can test that, I don't have a pipe that big to do that test. I am thinking to try and add a straight run someday down the wall, just not sure when that would be.

[@DonziGT230]

Did you test both impellers with the long hose to see which impeller performs better with the added restriction?

[@lindseyacresfarm]

OMG I can't believe I didn't think of that. Dangit. I was trying to think of every iteration of the test I could do, and I missed that one. Sorry about that.

[@DonziGT230]

@@lindseyacresfarm It's possible that one will flow more with minimal restriction and the other flow more with real world use restrictions in a shop. If your life is anything like mine you'll jump right on that test next time you have nothing else to do, so somewhere around 2086, give or take a couple decades. 😁

[@lindseyacresfarm]

@@DonziGT230 Very true :D sounds about right.

[@justonbohannan]

I just bought this unit. I haven't had time to put it together yet. Is its real life performance significantly better than a shop vac?

[@lindseyacresfarm]

Yes in my experience. My shopvac can't keep up with my planer, but this can when I have a good seal between the hose and the output of where the chips come out.

[@MaGa-man1776]

im thinking of picking his unit up would it be a significant upgrade from my wen 600 cfm dc ??

[@lindseyacresfarm]

I do not know. I actually looked at the wen, and I didn't go with it because of needing to run another 220 electric to that part of the shop. I just really didn't want to do that again. I was also able to find this for $100 so even with the upgrades so far I am still well under the brand new price. The nice thing about the wen it is it probably uses less electricity, and provides similar CFM since it already has the larger impeller.

[@alanrichardson7244]

Where did you get the impeller?

[@lindseyacresfarm]

Hi the second link in the description is a link to the impeller I bought. Hope that helps.

[@dougprentice1363]

Theres no need to explain what you are going to do before you do it. Just do it. Im not trying to be mean. But most youtubers do this. It adds so much repetitive time to video.

[@lindseyacresfarm]

Thanks. I am trying to get better about this. What I have been trying to figure out is how to do the stuff and tell why instead of the what. Just what is so much easier and comes out.

[@howardskillington4445]

That cloth bag is worse than useless. A pleated filter is needed.

[@lindseyacresfarm]

For sure. I want to test just blowing it outside and see how that goes. I have no neighbors close by and it will just blow out on old logs that are rotting at this point.

[@psychedelicguitarartbyjima3850]

[@harkbelial]

You should wear your mask together with your bra and high heels while you paint your nails.

[@stevehinton5300]

Seeing the reversed fin problems on other videos... .. IF the fins were correct on the new impeller it would be ALOT MORE efficient.. more cfm.. the fins are supposed to bring the air IN TOWARDS the center... too bad can't find the correct impeller..

[@lindseyacresfarm]

I noticed that too. If I had the skill level and knowledge I would be curious to try my hand at making an impeller. I have thought about trying to find info on if I can run the motor in reverse and switch the intake and outlet a bit. That seems like it could be a lot of work to make it work and i have a bunch of other stuff to do.

[@billy19461]

Where did you find the hose?

[@gustaveliasson5395]

The center is where the inlet is; fins are supposed to fling the air *AWAY* from there. Besides, it's not physically possible to do what you're suggesting; as soon as the impeller starts to spin, the air inside the impeller will be thrown towards the periphery by centripetal acceleration. So no, there's nothing wrong with the new impeller; it's the *old* one that's built wrong.

[@gustaveliasson5395]

​@@lindseyacresfarm You *cannot* switch the inlet and the outlet around. It is NOT possible. This is a centripetal blower; it rotates air really fast so that centripetal accelleration causes the air to move away from the center of rotation. As long as the impeller spins, the air will move from its center to its periphery, regardless of the direction of rotation. The only thing you can really do is change the blade geometry to trade static pressure for air velocity or vice versa. In this regard, the blades on the new impeller are optimized for static pressure (as they should be).

[@lindseyacresfarm]

@@billy19461 not sure why I didn't get notified of this comment, but I got the rockwell dust right 30ft hose.