How Much Torque Do I Need in an Impact Wrench?

If you buy something through a link in our posts, we may get a small share of the sale.

When it comes to loosening and tightening bolts and lug nuts, an impact wrench comes in handy. To do this, the wrench uses a twisting force known as torque. So, how much torque do I need in an impact wrench? 

How Much Torque Do I Need in an Impact Wrench?

The amount of torque you need in an impact wrench depends on the type of task you are doing. For instance, if you need to remove lug nuts from car tires, you will need about 350 ft-lbs of torque. However, for large construction projects like rail construction, you might need up to 700 ft-lbs. 

This means that there is not a standard torque in an impact wrench that you can use to accomplish every task. Using too much or little torque can bring out undesirable results. So, you’ll first need to understand how much torque you need for the particular task you are doing, then set your impact wrench to achieve that exact torque. 

Impact wrench

What is Torque and Why is it Important in an Impact Wrench? 

In a general sense, torque is a measure of the rotational force that causes something to rotate. In this case, it is the force that causes the impact wrench’s drive to rotate

This way, when the drive rotates, it can either loosen or tighten lug nuts or bolts. To be more effective, however, impact wrenches use a hammer mechanism instead of just the rotational force when loosening or tightening bolts and nuts. 

The hammer helps to provide more force and reinforce the drive when it encounters resistance. 

Can I Adjust the Torque on an Impact Wrench? 

Like we already mentioned, there is no standard torque for every task. However, this doesn’t mean that you need a different impact wrench for each task you are doing. You can easily adjust the torque requirements to achieve the level you are looking for. 

For example, when tightening a large stubborn bolt, you will need more torque than when tightening a small bolt. So, how do you adjust the torque to match the task? 

Most modern impact wrenches have customizable torque. Adjusting the torque on a cordless or electric impact wrench is as straightforward as setting the dial to achieve your target torque. However, when using pneumatic wrenches, you might have limited options when it comes to adjusting its rotational force. 

In this case, you can tinker around with the torque in one of two ways: 

  • Regulating line pressure: Involves regulating the amount of pressure from the air compressor
  • Regulating tool pressure: Involves passing pressure from the compressor through an air regulator then to the impact wrench. We only recommend this method if your impact wrench doesn’t come with an inbuilt air regulator. If it does, then you can easily adjust the torque directly using the regulator. 

Regulating Line Pressure

Follow these steps to regulate line pressure: 

Man testing how much torque does he need in an impact wrench
  1. Power on your air compressor and let it run until it reaches maximum pressure 
  2. Using an air nose, attach the air compressor to your impact wrench
  3. Slowly, reduce the pressure by setting the air regulator on the impact wrench until you achieve the required torque. 

Regulating Tool Pressure

Follow these steps to regulate tool pressure: 

  1. Connect a tool air regulator to the impact wrench 
  2. Connect the air nose to the regulator 
  3. Adjust the regulator until you achieve the desired torque 

How to Modify Your Impact Wrench to Get More Torque

While manufacturers do not recommend modifying torque settings beyond the recommended limits, it is still possible to do so. You should only do this if the impact wrench you have has maximum torque that is less than what is required for the task at hand. 

Otherwise, you should consider getting a new more powerful impact wrench or borrowing one. 

How to Increase Torque 

If you decide to increase impact wrench torque beyond the set limit, follow the steps below. 

  1. Disassemble the Impact Wrench using a 5/32″ Allen wrench to remove the rear plate then extract the motor and cylinder. 
  2. Create a new shape on the cylinder ports using a Dremel while taking care not to lose too much of the metal. Do this on both the front and back of the cylinder. 
  3. Open the exhaust ports on the cylinder to reveal the endplate then grind it too to enlarge the inlet ports. Ensure that both inlet ports are of the same size and leave a space for the screw hole. 
  4. Cut the paper gasket so that it matches the new ports 
  5. Clean everything and put the impact wrench back together.
Impact wrench

You should see a significant improvement in torque enabling the impact wrench to perform more high-torque tasks. 

What Happens if I Apply Excess Torque on an Impact Wrench? 

As logical as it sounds, over-torqueing doesn’t necessarily result in faster tightening or loosening of nuts and bolts. In fact, too much rotational force can break or crack the bolts. 

In other cases, when lug nuts are over-torqued, it can result in warping or breakage of brake rotors and even damaging the hub flange. This is because wheel lugs tend to flex under duress. So, when some lug nuts are overtightened, they can result in uneven tightening against the surface of the brake rotor. 

The uneven tightening causes the rotor to balance off-center and result in warping which is hard to undo. 

Related Questions 

How Much Torque Does an Impact Wrench Need to Remove Lug Nuts?

An impact wrench needs about 500 ft-lbs of torque to remove lug nuts. In most cases, you will need the same amount of torque you used to tighten the lug nut in order to remove it. So, if you over-tightened it, you might need more than 500 ft-lbs torque. 

Conclusion 

Different tasks will require different measures of torque. That is why we recommend that you get an impact wrench with adjustable torque settings so you won’t have to use a different one for each task. While you can increase torque on your impact wrench, it involves a complicated process that you might not be willing to undertake. 

An expert at home repair, remodel, and DIY projects for nearly 40 years. His first experience came in completely restoring an antique home. Completely redone from the inside out, and restored to its original form, the home is a featured design by renowned Southern California Architect Cliff May, considered to be the father of the California Ranch Home. Now Dennis spends his time on fine woodworking projects and tool comparisons.