Compressor Newb Needs Advice

[dilettante]

hi,
I recently purchased a small 8 gal compressor from HF. It is the first compressor that I've ever purchased. I plan on using it for filling tires and clean dust from things here and there. From reading this board, I realize buying a big a compressor as I can and growing into it is the standard advice, but anyway...

Here's my problem. I've had no difficulty filling the tires of my compact car to 32 psi. But, I'm having a heck of a time filling my van to 35 psi. I've played with the regulator from 40lbs to 90lbs and I get a small trickle of air at each.

Am I doing something wrong? Or, is this compressor just junk? Or, both? Appreciate any help or advice on this issue...

Here are the "specs" - I realize it might not be "actual" performance.
* 2 horsepower motor (rated)
* 115 PSI maximum
* Air delivery: 5 SCFM @ 90 PSI; 6 SCFM @ 40 PSI
* 8 gallon tank capacity

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=40400

 

[GT89mustang]

What does the 2nd gauge for the line pressure read?

 

[35mastr]

Pull the regulator off and run the hose straight to the compressor.If it works better than you need a new reulator.

If not put it out front with a FREE SIGN and move up to a real compressor.

 

[dilettante]

What does the 2nd gauge for the line pressure read?

Somewhere between 80 and 100

 

[dilettante]

That might be what I need to do.

What really matters in terms of getting air into a tire? SCFM? PSI? Thanks.

Pull the regulator off and run the hose straight to the compressor.If it works better than you need a new reulator.

If not put it out front with a FREE SIGN and move up to a real compressor.

 

[35mastr]

PSI.

The pressure going in has to be higher than whats already in the tire.

CFM is more impotant when running air tools.

 

[dilettante]

Thanks, 35. That makes sense.

Supposedly, I can get my compressor to 115 psi. Is the compressor just junk?

Do I have to go for something like 175 PSI?

PSI.


The pressure going in has to be higher than whats already in the tire.

CFM is more impotant when running air tools.

 

[Chris Adams]

I don't know what you are setting or doing wrong but any compressor should do your tires. I mean any. I do my motorhome tires (+65 PSI) with a quarter horse five gallon when I'm on the road. Takes a few minutes but it fits in a tiny compartment and is handy. I just run the jenny on the motor home to supply 110 volts and I can air up the tires or the air bags anywhere.

You need 1 lb more in the tank than you need in the tire.

OK, not even 1 lb, but you see what I mean. The more pressure the faster is all.

If you have the end on the stem, the end is adjusted properly, the stem core (valve) is correctly installed, then you need a tank with more air in it than the tire. Period. Air flows from the higher to the lower.
You need more than 125 lbs only if you carry more than 125 lbs in your tire.
Not ****** likely.

You should have two gauges. One shows the pressure in the tank. The second gauge is for the regulator. It should show the amount of air you are feeding to the chuck (that's the dingus you use to put air in something).

Say you want to put 45lbs of air in a tire, the first gauge must show more than 45lbs of pressure. The second gauge must ALSO show more than 45lbs of pressure.
If your first gauge shows say 80 lbs, and your second gauge shows 35 lbs, you are putting 35lbs of air into a tire. If your tire has 34 lbs, you will slowly increase it to 35.
More pressure equals more speed.
Guys who are telling you that you don't have enough compressor are just being jerks, or yanking your chain.
It's not about horsepower, or tank size. It's all about the pressure. Tank size means you hold more air and can fill more tires before the compressor goes on.
Horsepower just means you have to wait longer for the tank to fill.

CFM is only important when you are spraying air, like heavy power tools, spray guns, sandblasters. Tires, if you don't have a lot of CFM, you just take longer.
The specs on your tank means you can fill any truck tire in common use, easily.
Your chuck may be bad, adjusted wrong, your valve stems may be out too far.



A '2' horsepower compressor, by the way, will draw 1800 watts or so. If you are curious about the actual power of the compressor, check the wattage on the information plate and do the math.

 

[Gary S]

It should work for you. I don't know why it doesn't. I have 2 compressors in my shop. I have a small 110v compressor for small jobs and my big 220v one for heavy use with air tools and painting.
My small one is similar to yours. It is about 5cfm and has a small 20 or so gallon tank. It easily pumps my load range C pickup tires to 55 psi when I need to carry heavy loads. So, yours should easily do the same thing. My small compressor is even adequate for my IR Thundergun impact wrench because it is intermittent use so the little compressor can catch up. Obviously, it can't handle a DA sander or a paint gun, but I have the 220v compressor for that work because it puts out 18.5cfm for bigger jobs.

 

[dilettante]

What you say is pretty much what I *thought* would be the case. That is why I'm confused. I'm going to try using a different air chuck and see what happens. We'll see...

It should work for you. I don't know why it doesn't. I have 2 compressors in my shop. I have a small 110v compressor for small jobs and my big 220v one for heavy use with air tools and painting.
My small one is similar to yours. It is about 5cfm and has a small 20 or so gallon tank. It easily pumps my load range C pickup tires to 55 psi when I need to carry heavy loads. So, yours should easily do the same thing. My small compressor is even adequate for my IR Thundergun impact wrench because it is intermittent use so the little compressor can catch up. Obviously, it can't handle a DA sander or a paint gun, but I have the 220v compressor for that work because it puts out 18.5cfm for bigger jobs.

 

[intheusa]

Thread update.

Bought this same compressor a few months back and very happy with it. In fact only paid $70 and thought I would test drive it.

As far as inflating tires, it did a great job my 3/4 ton HD.

One must set regulator at 90 PSI or I just use it wide open. Do not set compressor regulator at your tire pressure (will take forever.) Check your tire pressure with a tire gauge that is known to read correctly.

Also not to be insulting but you must use compressor oil and fill it correctly.

In fact I'm considering buying a 2nd one and running it on seperate breaker and if at times I need capacity combine them with air hose tee for 10 to 12 SCFM capacity. I do think this compressor generates close to 6 SCFM @ 90 PSI.

In closing this compressor is not very noisy.

 

[darkwingbenny]

I have had the same exact compressor 40400 for the last 5 years. While it is not a pro 2 stage 80 gal compressor, it does what I need it to do well. These tasks include filling tires, air ratchet, impact, and cut-off wheel.

Some good advice above. Check oil, regulator and perhaps get a better air chuck.
I use one similar to this: http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=95583

 

[Dale B]

Are you trying to inflate the tires thru a valve stem extension ?? Some of them don't work for s**t , I have to pull the Wheel cover and hook onto the stem direct.