Impact Wrench Recommendations

What type of impact wrench would you recommend, for general automotive work? I know that's a pretty broad question, but with so many brands and types of wrenches out there I'm not sure what I really need. A generic one I borrowed from someone (unsure of the power rating, it weighed about 3 lbs) was unable to budge spindle nuts or any seriously-rusted bolts.... basically anything I couldn't turn by hand. Ingersoll-Rand wrenches come highly recommended, but they're very expensive and there are quite a few different models.
Thanks for any advice.

I think you might be a little bit confused. Impact wrenches are for working quickly. They are also excellent for reducing strain on the person using them. They provide faster work with less effort.

When it comes to budging stubborn fasteners, turn to other tools. Breaker bars, slug wrenches, nut splitters and, of course; the ever popular oxy-acetylene "wrench" fit here.

If you insist on using pneumatic power for these tasks, size matters. 1/2 impacts are capable of only 600-700 ft/lbs. For true brute force you'll need at least a 3/4 drive rotary hammer, 1" is even better. With a whopping 1000+ ft/lb output (some can hit 3000!) they can crank off (or snap off, given the chance) far more then the light duty units.

Brand name matters very little in terms of performance, the main differences are ergonomics and longevity. My craftsman 1/2 impact, 3/8 ratchet, and air hammer function just as well as Snap-On, Ingersol Rand or Campbell Hausfield units I've had the opportunity to use. They don't feel as good in my hand, tend to vibrate more, and most likely won't last as many working hours. But performance wise, they were all somewhat equal.

No matter what you buy, the important thing is having the air supply to back it up. You can buy the biggest best air tools on the market, and they won't do squat without enough air. Quality High torque 1/2 Impacts need over 4 cfm when running at 90 psi. Big rotary hammers can require as much as 7, maybe more.

In closing I'll generically answer your question, though, since it's the information you did ask for.

Favorite 1/2 drive medium duty general service unit: Snap-On Model IM6500HP

Favorite light duty: Snap-on IM3100 Versa drive (converts in seconds between 1/2 and 3/8', and has long and short anvil options)

Favorite Butteryfly: Butterfly impacts are useless

Favorite 1/4: also useless

Favorite Heavy Duty: Blue Point 1300A 1" drive

If you thought Ingersol Rand tools were expensive, sit down when when you look up the prices on these.

I agree with Ragtop that for really stubborn fasteners you should use a long breaker bar and good socket.

For the impact, what are you other uses, do you want something that's portable, do you want something that is very versatile, do you have a good air compressor with decent CFM capacity?

Probably one of the my most-used tools in my garage is my cordless 1/2 drive impact. I've had DeWalt, Milwaukee, and Makita. Currently my favorite is the Makita due to the size, quality, price, and the fact it's a Li-ion system so it's always ready to go when I need it and the batteries charge up quickly. I have both the large one (BTW450) and the smaller one (BTW251) and there are few tasks that the BTW251 won't due and I need to resort to the BTW450. '

I also have an Ingersoll-Rand 2135Ti which is a nice, powerful impact, but the convenience isn't there. I have to fire up the loud air compressor when I want to use it, oil it, and drag around an air hose. The cordless fits in most places, I can take it with me on trips in case of a flat (and I haven't had one since carrying the impact with me), etc.

-Rod

For light automotive work (wheels, rusty bolts, etc) I would say that Cambell Hausfelds better model would do the trick. They have a cheapy one for something like $27 that wouldn't turn a corkscrew, but the one I used for about 10 years was in the neighborhood of $125 and was more than adequate. I eventually upgraded to an Ingersoll Rand, but I still have that CH model for a spare.

Your points are well-taken.... at this point I don't think I can justify the expense of both an impact wrench and oxy/acetylene setup just to remove a half-dozen nuts and bolts. I'm going to see if I can borrow or perhaps rent some equipment just long enough to do the job, which should take less than an hour.
If I should end up making a career or even serious hobby of automotive work later on, then I could justify spending a few thousand $ on tools. Until then, I'll just have to borrow stuff or when possible, take the longer and more laborous approach to these problems.

http://www.thetoolwarehouse.net/shop/IR-231C-KS.html
This wrench will outlast you, is tough, strong enough for most anything and easily rebuilt if you do use it up.

Note the CFM consumption, minimum at load. I don't think many DIY compressors will keep up with that to get the full torque rating.

-Rod