Well, I purchaed a compressor, 15 gallon peak 5hp. With it I purchased a 1/2 impact wrench. I'm just not getting the power from the impact wrench needed to take lug nuts off which is its primary purpose. Now I read the directions for the wrench and it says it needs a minumum of 3/8 hose size, and recommended a whip (short piece of hose). What is strange is the wrench came as a kit with a quick connector which really bottle necks the incoming air. Also, it recommends only a 30 foot length of hose.

The wrench appears to work better without the quick connect when I attached it directly to the air hose, the wrench has noticeably more power. (When I tightened some lugs it was able to torque them to around 80 ft/lbs which was good.) Also, my air hose is 60 foot but does that really matter? I just expected more torque from this wrench, well over 80 ft/lbs. I have the setting turned all the way up.

So have a connect this wrench up properly, and how are you guys doing this?

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87 Fiero GT (3.2 Turbo)
E-mail: davidfiero@hotmail.com
www.angelfire.com/pa5/davidfiero/

I use a torque wrench to properly tighten my lug nuts. I have my eyes on a 25 gallon oil less compressor from Craftman. I would only use the air tools for dismantling things, not to assemble them, unless the torque setting isn't that important.

I have the same problem.

As best as I can figure, it's because the compressor just doesn't have a high enough flow rate. I think my tank is a 20-gallon tank, also 5 peak HP motor.

Reading the directions for my TWO impact wrenches, it says I should have no trouble using them. But neither one pulls much torque.

I did have somewhat better results after oiling them, but all told it looks like a bigger compressor is the only way to fix the problem.

You can get impact wrenches with low air usage (like 3 CFM at 90 PSI) but they're expensive.

Ed

More likely than not it's because your impact wrench is not rated for very much torque. The low cost ones can barely generate the 100 ft-lbs needed to loosen lug nuts whereas good ones can generate over a 1000 ft-lbs.

Also, you need to set the pressure under flow conditions. If you set pressure to 90 psi while it's static the pressure will drop to about 70 psi under flow.

Also the size of your tank and hp of compressor have almost nothing to do with an impact wrench. A smaller tank means more cycling of the compressor and lower horsepower means it will run longer, but torque is all about pressure, (90 psi) and how effectively your wrench can convert that into torque.

[This message has been edited by jscott1 (edited 07-27-2005).]

5hp = around 3 true hp ...Time For An Upgrade

Not To Long Ago I Worked On A 800 Hp Unit ...Of Course It Was The Size Of A Train ..But Hey

And No Thats Not Me Above lol

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"This car is so good looking its almost indecent. - AutoWeek on the new 1986 GT"

Chilliwack Fieros
MSN Messanger tylercaddick@hotmail.com

I am no engineer, so I just try to figure things out as best I can. I figured the tank size had little to do with the wrench performance as I observed the pressure dropped little. As best I can figure the line size, its diameter, was most likely the culprit. Funny, there is no indication on the specifications as to the torque output of the wrench. It mention a line less of no more than 30 feet (I have 60 feet). Could that be effecting performance?

This is disappointing because the main reason I purchased the compressor and wrench was to remore lugs. If this is it, I can do a better job with a breaking bar!!!!

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87 Fiero GT (3.2 Turbo)
E-mail: [EMAIL=david88@peoplepc.com]
www.angelfire.com/pa5/davidfiero/

There are several things that will affect you air wrench. First is volume of air, if you have small 1/4 inch hose get larger 3/8 or 1/2 inch hose. If your wrench calls for 3 cfm to run and the hose can only delivrer 2 cfm to it, it will not perform. Second is pressure, you will want to set you regulator to 125 psi. 90 psi is bare minimum. Third is moisture in the air, get a good air drier, as the impact is working the moisture freezes inside the wrench causing low performance. Last is lubrication, make sure you oil your wrench with a couple of drops of air tool oil befor and after each use. This will help keep it clean and minimze friction losses inside the wrench. And as mentioned earlier the type of air wrench will make a huge difference in the output torque. The size of the tank is only reserve capacity it keeps the compressor from cycling on and off. size of compressor has to to with how fast it will pump.

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Signature courtesy of MinnGreen.

[This message has been edited by Fiero STS (edited 07-28-2005).]

I keep my compressor set for 125 pnds at regulator and all my tools have their own pressure adjusters. Does your impact have a knob at the bottom, most have and you have 4 or 5 different settings.

I'm no engineer either I may be wrong but, my thought is that it only takes about a second to break a lug nut loose. As long as you have the recommended pressure (usually 90 lbs),then 1/4 inch hose *should* work. For high CFM constant applications, (die grinding, drilling, painting), then you NEED the flow a 3/8 hose will provide.

It could be the torque wrench itself. I bought a cheapie one once (29 bucks).. I had to have a great big 1/2 inch drive breaker bar handy when taking off wheels because there were always some nuts that were too tight for the wrench to remove.

The cheap 1/2 inch drive guns run about 250 foot-pounds of force. A good one will be 450 foot-pounds or higher. Expect to pay over $100 for a good impact wrench... Also, is yours a 3/8 drive or 1/2 inch drive.. The 3/8 drive guns are usually smaller and don't have the same punch.

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1988 Fiero Coupe 2.5L
1990 Trans Am GTA 5.7L

[This message has been edited by Poncho Jim (edited 07-28-2005).]

A 1/4" hose is too small. As the diameter of the hose decreases the proportion of the hose wall to diameter increases (more relative surface area). As a result the friction at the air/hose wall interface is also proportionally higher. The smaller hose size and higher friction loss results in much less air being delivered. A smaller hose cannot provide the required air flow even for a short duration at the same pressure. Additionally, the length of hose used also affects the friction loss so that a longer hose will deliver less air under the same conditions as a shorter one.

Nolan

I have a 3/8 hose.. My air tools don't work worth a dang either and I can't figure it out.. I SHOUDL be putting out well over 10cfm, at 120psi.. My cutoff wheel jambs at the slightest thing, and the impact won't remove a lug nut (I can ALMOST hold it with my hand).. Those are both CH tools though.. It's gotta be the tools..

I have 3/8 line that's 60 feet long. Not sure of the make of the impact wrench, but till now I thought they were all pretty similar. Could the quick coupler be effecting performance as they size down to like a .25 of an inch before entering the tool?

If I have I will have to search out a good wrench to purchase. What are some good decently priced air tools?

I am lucky, I have a 60 gallon C-Aire compressor.

The first 1/2" impact I had was in a kit with several other air tools and it came from Sam's Club.

The impact didn't work on lug nuts even through a 3/8"hose at 140PSI.

I broke down and purchased a Craftsman 1/2" impact, here's a link to the one I bought.
http://www.sears.com/sr/javasr/product.do?BV_UseBVCookie =Yes&vertical=TOOL&pid=00919905000&subcat=Automotive+Air+Tools

It's about $200.00 but it was worth it as it out performed the other cheaper one by leaps and bounds at 90PSI.

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Where will the road take you today?

Some helpful links I've done
How to remove inner door panels, with pics.
How to remove outer door panels, with pics.
How to make rear coil-overs using factory struts, with pics.
How to replace the rear bearing hubs, with pics.

[This message has been edited by fierohoho (edited 07-28-2005).]

length of line is a problem and also diameter of line should be 3/8. You don't say what brand of impact but just about any 1/2 in impact should have no problem with lugnuts. I use a good 3/8 in impact to take mine off. It sounds like you have a combination of things cutting down the power to the impact. Another thought - do you have the power setting on the impact turned down? How long have these lug nuts been on? They could be frozen in place.

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Notchies rule, fastbacks drool

I had the same problem with my air wrench when I bought it. I swapped to a bigger hose, the one I got with the compressor was the thin spiral plastic one and the new one I bought looks like a reinforced garden hose. Made a huge difference and no problems with the lug nuts even though my compressor is pretty small.

Yeah, that is pretty much what I have, an inexpensive kit that included the air lug wrench. I do have the setting turned all the way up on the wrench. The lugs are not frozen, but even so I would think that it would be able to break them loose. I guess I can search out a short length of hose, but it is a 3/8 inch line.

I oiled it a little and it did improve a little, generated more torque.

Tire lugs are typically torqued to about 70-80 ft/lbs? I should have not problems.

If you switch to a 3/8 hose the length shouldn't matter too much. I have a 50 foot hose on mine with the quick disconnect and it's strong. Also adjusting your pressure up to about 125 psi will give you the dinamic pressure at 90 like I said earlier.

If all you wanted was to loosen lug nuts maybe an electric impact would help. I borrowed one from "Aqua-Man" to rotate my wheels. 8 luggers on a van.,, Think it was a Sears model.
It was a bit of a fight but something had to give and I can assure you it was'nt the electricity. On a Fiero it should be a piece of cake.
Problem with air guns & limited flow and your screwed. With electric you can at least go down in flames trying.

ps: Did I tell you about the electric jack hammer story ???

Get a real impact wrench... IR or Aircat. 90 psi is plenty of air pressure, the fitting is effecting the gun, but the gun being crap is the real problem.

I have an IR dual hammer that was rated at 650lb/ft torque when I got it about 10-15 years ago, still works great and never been rebuilt.

Aircat has one rated at 1000lbs... that should get the lugnuts tight enough :-)

http://www.brandsonsale.com/ht-001043.html

A set of torque sticks or never turning it past first click and just running the lugnuts down lightly with a real impact is highly advised. I always hand torque wheels myself or use a torque stick matched to my impact on my hoses.

[This message has been edited by Scott-Wa (edited 07-30-2005).]

My old Chicago Pneumatic 1/2" impact (25 years old), got tired, and would not break lug nuts torqued to 90 ft/lb. anymore.

Then I got a good Ingersoll-Rand rated at 550 ft/lbs. It is one bad boy. It works well with both my little compressor (5hp, single stage,20gal) and the big one (7hp, two-stage, 60 gal). I use 3/8" lines.

I think it may be the impact tool more than anything.

quote Originally posted by Scott-Wa: Get a real impact wrench...the gun being crap is the real problem.

This is essentially what I said in my first post. I see a lot of people bought the SEARS compressor or similar and it comes bundled with a set of air tools and hose, but they are crap air tools. The better air tools can do a lot more with 90 psi than the crappy one can.

My first air tools were CH also, and the 1/2" impact gun would not remove a lug nut, even with the rather large compressor and hose I ran at home, same results in a "real" garage with thier compressor. The air ratchet made more noise than torque. Same compressor and hose, my "Titanium" IR 1/2" gun will just about break the lugs off if you're not careful. ("supposed" to be 1,000 peak removal ft lbs...) Even my 3/8" Snap-On (got a great discount on it, so I had to buy it... ) gun has more power than my old CH 1/2". I still use the CH air chisel though, because I can beat the crap out of it and not care much. Same results with the cutoff tool, more noise than power. I didn't know what I was doing wrong with the CH impact gun, 'till I used a real one and saw the difference. Unfortunately with air tools it seems you get exactly what you pay for.

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Bob Williams
Multi-colored '86 Mutt, a work in progress! (3800SC running great! Fixed the bent roof, now I need an intercooler! Yeehaa!)