Help with air impact wrench

[Mark A]

I hope someone can provide some assistance, now that we have a bit more time on our hands (I’m working from home but no longer have a 1hr commute each way) I would like to improve a few things in my garage.

finally got to sealing the floor and painting it, I have installed more shelving in it but could probably do with more. And started looking at why I don’t make more use of my air compressor as I have a load of air tools on the shelf. Then I remembered - poor performance of the impact wrench.

I have a 3hp belt drive SIP with a 100L receiver and a quoted 14.5 cfm output. I have tried to improve things by bypassing the standard regulator and taking a direct feed from the receiver (using the Burisch hi flow kit from gt air). I have a 13mm hi-flow kit going to a filter regulator and a 10mm line to the gun. I have tried hooking up a pressure gauge at the gun and can confirm that I am getting 90psi at the gun when operating. Despite this it still isn’t man enough to undo wheel nuts. Any thoughts??

The gun is a SIP 1/2” unit from one of their air tool kits, but I also have a another gun which was purchased separately (can’t remember which make).

 

[daveenty]

I have a similar specced compressor to you and also had trouble with air tools. Initially I was also messing with the compressor settings, adjusting blow off valves and such just to try to get a bit more power but then I thought I'd replace the rattle gun. It was a cheap and nasty supermarket thing so that could well have been the reason for the poor performance. I replaced it with a US Pro 8513 which came recommended from several places and I've never had to resort to a breaker bar since. Bear in mind it's a heavy lump...

I can't even remember where it came from, quite possibly eBay, though I've had it several years now and it's still working fine.

Incidentally, you're probably aware that the output figure quoted by the compressor manufacturers is a lot less relevant than the FAD (Free Air Delivery) figure? A lot of makers quote the CFM but are woefully lacking in the FAD which can also cause problems with many air tools, DA sanders in particular.

Edit to add picture of gun: -