How to get highest CFM from T30 234

[Kcscott11]

Apologies in advance, I've been digging for information the past several days and honestly 90% of my results lead me to this forum, and this category so I thought you guys may be the best to try to gather decent info from. I explained my situation and requirements im detail but its a ton of info, I did a basic recap at the bottom of the post that basically just listed the main points/questions.

Hey guys I'm building a compressor. I have been collecting pieces a couple years now and have had everything I needed for quite some time except the proper fittings and outlet line which I have finally bought amd received today.

However the last few days I have been researching the pump more deeply than the past as I had never located the proper info on the data plate other than T30. I didn't realize this was a 234, and didn't realize its basically the smallest and oldest of the t30 2 stage family. From what I've seen its intended for around 750-800 RPM but I've failed to find any manuals other than parts manuals that provide any real literature. I do know the newer replacement 2340 is spun around 1000rpm at 14cfm at 175psi, however I get the understanding it is a way higher output than its predecessor.

Basically I run a small body shop and have been striving with compressor issues and decided it was time to put it to a rest. Im not planning to run this pump at 175psi, perhaps 120max but most of my tools are regulated down to 90-100psi and my spray guns are anywhere from 15psi to 40psi.

However all of my DA sanders **** air and at times are ran around the clock. I run them at 75-80psi although they are intended for 90 if im not mistaken. So basocally, If Im remember correctly, I honestly need 17cfm at 90psi. I don't think this 234 is capable of that, however in top performance what should I expect out of it max? I do have a 5hp motor but can put a dofferent pulley on it to lower rpm.

Whats the highest rpm that is safe to run this pump at? And what cfm would I approximately have at say, 40psi, 90psi, and 120psi, and just for its and giggles i guess 175psi.

Its going on a skid with my 5hp motor mounted on a 250 gallon tank, to which I added a bottom drain valve and then hydro pressure tested at 250psi for 2 hours. I figure that should be sufficient testing for my purposes.

If the cfm is totally lacking, I know.there are rebuild kits, and basically every part available for it to repair and keep new condition... is there any upgrades I can do? Can you change to larger heads for example, based on what I've seen the lower units all appear to be similar on the older models, with the primary difference being cylinder size/top end.

Or is there anything I can do to allow the pump to reliably function at 1000+ rpm, is any of that even necessary at my lower pressures I plan to run?

Or am I never going to get the output I really need?

Would i be better off selling this pump and buying the 5hp Mcgraw 175psi pump from harbor freight? If it last a few years and I grab it on sale for around $200 ots basically cheaper than a single replacement head for the t30. Basically if it last 3 years and needed replaced, it would not really cost much more.than if the t30 needed maintenance or a rebuild kit in the same time frame. The hf 5hp pump boasts, 14.8 cfm at 120psi which, would likely do for my purposes, especially when paired with my tank size and the fact that there will be start and stop times where I am not using air for a few minutes if it it is in need of catching up. Hell I considered installing two of the 5hp Mcgraw pumps amd calling ot a day.

All in all, im just ready for a compressor I can use to plumb the shop and let be for a while so I can focus on working.



I know I spewed a lot of disorganized questions and data throughout thay so here's my book down



T30 234 Max reliable rpm

What CFM at that rpm at 40, 90, 120psi or approximately

Can the pump be upgraded, ie: heads from different model of this family, upgrades to allow higher rpm reliably, etc

I really need at least around 12-13 cfm at 120psi and more would be better, would I be better off just buying a 5hp Mcgraw 175psi which looks 14.8 cfm at 120psi amd hoping to het a few years out of it, sire I can catch one for 200 on sale soon otherwise, the 229.99 they have it priced for currently is still the price of a single head on a 234.

Eventually if this 234 can't meet my demands I will find a bigger one, im a huge fan of reliability, longevity of life, and reliability instead of throwing things away amd replacing them every few years.

Which T30 would be recommended for my needs, what if I was considering hiring a guy or 2 to help around the shop who may or may not use air at times?

Should I just bite the bullet and find a different type pump all together, say a 7.5hp and from what manufacturer? I'd like to find my pump for at least $600 or less especially of i am going to be upgrading to a 7.5 hp motor as well smh.

 

[GeoBruin]

Lot of info there and I'm sure you will get some suggestions ranging from using the pump you have, to replacing it. You may be able to rebuild it, but I highly doubt there is any way to "upgrade it" to get more flow. The flow is a function of the displacement and the rpm. Changing the displacement is not worth it, and running it over the spec rpm is not a good idea either. All that said, let's make sure there's even a need for an upgrade.

You keep talking about how much pressure (psi) you need, or would run the pump at, but you can't change the pressure of the pump (without significantly modifying/replacing the pump internals). It will simply build whatever pressure the discharge end of the second stage cylinder/valve is designed to build (which appears to be 175 psi) Even if you speed the pump up, it won't build more pressure, it will just discharge more air (cfm) at that max pressure.

What it sounds like you're really interested in is flow. Yes, speeding the pump up will increase flow. It will also increase heat, noise, and wear on the pump. It looks like the 234 was designed for either a 2 or 3 HP motor which allows it to make 7.8 and 10.6 cfm respectively (though we aren't told at what pressure).

Only you can decide if that's enough flow for your use cases. But remember the amount of air you can flow instantaneously is not dependent on the pumps throughput. If you charge your tank up to 175 PSI, and then start to flow air from the tank, depending on what restrictions you have downstream in your distribution system, you will be able to flow anywhere from dozens to hundreds of CFM. It's only once your tank drops below the cut in pressure that your pump becomes the limiting factor. If you run a 250 gallon tank, that's a lot of air you can use before your compressor even kicks on. That said, for something like a DA sander, when your compressor kicks on, it's going to run constantly and will not be able to keep up.

Running a 3hp motor/pump on a 250 gallon tank really doesn't sound like a great idea. Your pump is going to run constantly trying to fill that big tank which means it's going to be very hot and you're going to get a ton of moisture in your air. It will also likely reduce the life of your pump. Now there are lots of debates about this here on the forums, and some will say that the number of hours the pump runs over its lifetime will be the same regardless of the size of the tank, but within a particular session of grinding or sanding or painting, etc. the fact is the pump is going to run more than a larger displacement pump.

 

[Kcscott11]

Thank you for the reply. Its sad the way they (manufacturers/advertisers in general) rate things, you can just assume that, according to the chart you shared, at 2hp it would be 7.59cfm at the specified 175 psi, and 10.80 cfm at 175psi using 3hp. I mean, its completely plausible that is what they mean, especially considering things weren't quite so misleading when this pump was likely manufactured. However its definitely not worth assuming.

What I mean about not running the pump at 175psi may be worded misleading, however what I mean is I am likely going to set my cutoff switch at 120-150psi, meaning the pump will not be forced to bring my tank pressure up to 175 psi. However the more thought I put into it, the more I realize that if I do let it fill the tank to 175psi and regulate my output from the tank to 120, it will give the pump a little extra breathing room which seems.like it would benefit from long term

I am guessing the reason I haven't been able to find solid cfm figures for this pump is because they don't officially exist. Interestingly.they can be roughly calculated by draining your tank, and timing the fill time, however if you want dead on numbers you have to account for atmospheric pressure and the volume of air in any attached lines including the plumbing between the pump and tank.

I have everything here now, I suppose I'll put it together and just see if it can keep up.

I will also attempt calculating the cfm to see if I believe the pump is even outputting its potential. Truth is, it may need a rebuild. I have played with it enough to know ot will make air but never truly ran it, for all I know I'll wind up needing to install an entire aster overhaul kit in this thing. It seems that in my situation, it would financially make more sense to aquire a larger pump with the money it would cost to completely rebuild the pump.

However I do have several 2-3hp motors here as well as multiple 30+ gallon tanks here, if all else fails and I need a new pump for the large tank, I may put this pump on a smaller tank as a back up, so long as I can get by with minimal parts to make the pump work well enough, hopefully just rings and valves, which I believe are the primary causes of loss of building the proper pressure, or cause of it taking longer than it should.

To be honest if it comes down to it and this pump 100% just isnt going to cut it on this tank, I may build a compressor from my extra parts and sale the unit whole in order to finance a bigger pump, I may even build a portable gasoline powered compressor, just to make it a little more valuable to the right buyer. I have 2 or 3 good running Honda gx engines floating Round here in one of the buildings.

I honestly.habe considered running 2 of the harbor freight 5hp Mcgraw units, the tank is plenty huge enough to mount everything, my main hold up is,
1. I really want a high output t30. Honestly I just like the repairability and they have a kit the longest track record you could ask for.

2. Buying 2 of the pumps is really no huge investment considering the claimed output I woukd get, however when you also account for the fact that I would also need another 5hl motor, and then really consider matching motors may be better for the application, suddenly things start to get pricey.

3. It sure would be nice to use what I already have here instead of investing a ton more money into the project, especially considering, I have EVERYTHING, down to the last reducer, then only thing I may consider is buying some fresh compressor oil. Other than that I have done my research, used my calipers, checked all my thread types and gotten the correct adapters and reducers and other fittings, along with the pressure switch, gauges, relief valve, etc. There is very little standing between me and putting everything together other than time.

 

[American Locomotive]

The IR-234 has a smaller displacement than the more modern version. Spinning the pump faster than it's intended will generate more air, but it's going to do it inefficiently. It's going to make a lot of heat, and likely have reduced lifespan. I doubt the compressor is going to throw a rod or anything like that, but you would be better served by getting an actual 5HP rated pump and spinning it at its rated speed. I can't comment on the HF pump, other than that its CFM rating seems a bit low - probably not a terribly efficient pump.

Also, is your air tank actually a genuine air receiver rated for 175+ PSI? Or is it a propane tank? You may want to consult with your business insurance and also your state regulations. I know in some states, a tank that size would be subject to routine inspection and certification.

My unsolicited two cents: If you're running this body shop as a business as your primary/only source of income, and you plan on doing it for the foreseeable future, you shouldn't be messing around cobbling together junk that might let you down. Save up, buy a complete Saylor-Beall VT735 for $4k, then park it in the corner and let it run trouble free for the next 20 years.

 

[Chris_Hamilton]

My unsolicited two cents: If you're running this body shop as a business as your primary/only source of income, and you plan on doing it for the foreseeable future, you shouldn't be messing around cobbling together junk that might let you down. Save up, buy a complete Saylor-Beall VT735 for $4k, then park it in the corner and let it run trouble free for the next 20 years.

I second that. Saylor -Beale, to a lesser extent Champion or Quincy.

 

[u3b3rg33k]

Running a 3hp motor/pump on a 250 gallon tank really doesn't sound like a great idea. Your pump is going to run constantly trying to fill that big tank which means it's going to be very hot and you're going to get a ton of moisture in your air. It will also likely reduce the life of your pump. Now there are lots of debates about this here on the forums, and some will say that the number of hours the pump runs over its lifetime will be the same regardless of the size of the tank, but within a particular session of grinding or sanding or painting, etc. the fact is the pump is going to run more than a larger displacement pump.

the moisture you get in the tank depends 100% on what's in the intake air, and the tank temp. the lower the tank temp, the easier it condenses out.

 

[Spareparts]

Where are you located, I have used one Co. since 1996, have bought 5 compressors from them and they always speced the
compressor's to meet my needs at very reasonable prices. The compressor in my shop is 5hp 18.4 cfm 80 gal tank in 1996 $1,050.00
The compressor head runs at 560 RPM, this unit has never been shut off unless power goes off. The other units were 7.5hp
and used in commerical shops, tire repair, enging rebuilds, sand blasting, body work, by multiple people at the same time.
What I am trying to say is get ahold of a Co. that this is their business, their bread and butter and have them spec. your needs
for now and in the future. The Co. is North Central Air, in Downs Ks. told them what I was using it for and they did the rest, I was
severlk injured in A accident when I ordered mine, they delivered it to my home shop, unloaded and sat in place, wired it up and
let it run. All of this for no charge, that is why I always go with them. Pro Service to their Customers.

 

[stonesfan68]

The 234 was designed for 2 or 3HP operation. It turns at ~1000 RPM with a 3HP motor. IR used a 5HP motor and spun it up to ~1500 RPM so they could have a cheap 5HP machine to sell at Home Depot and Northern Tools. Call your local IR distributor and have them send you the engineering data pages so you can sort out the correct pulley and motor size.

Find an IR distributor

Turning a reciprocating compressor at a higher speed will lead to higher maintenance and a shorter life. That's just the facts.

 

[Steve_P]

As said, if you're actually running a "real" body shop as a full-time business, you need a real compressor; not cobbled together junk. Having a reliable dry air supply, capable to deliver in excess of what you could ever draw, is going to determine your ability to complete work, and thus actually make money. Trying to win the Tour de France on a tricycle is typically not the way to succeed.