Air Box Mod on a Hardbody D21/ Pathfinder WD21 and R50 Pathfinder (Cold Air Intake style)

This mod is similar in technology as a Cold Air Intake system. You should get 1mpg better and more power, with an increase in noise. Tools needed 10mm socket and phillips screwdriver. 1" drill bit and electric drill. The w/d21 mod is basically modifying the air box that houses the air filter via some extra holes. The resonator in the fender can be discarded later. 

The R50 mod is basically modifying the resonator (muffler) box that is hidden in the fender not under the hood. The air box that houses the air filter is connected to the resonator box via a huge hole.

Benefits to this mod:

  • Under hood looks stock
  • Sounds better.
  • More responsive.
  • More power and torque with a intake noise increase
  • Cheaper than aftermarket kits that discard the stock box.
  • Uses stock filter.
  • Uses stock quality hardware.
  • Works best with a K&N type oiled filter to keep water out.

 

W/D21 version

  1. Remove stock air box

  2. Drill lots of 1"holes all over

  3. discard extra plastic tubes and bag of ???

  4. Reinstall box with oil based filter.

 

Engine was breathing through a tiny tube. That big tube dead ends in the resonator in the fender.

 

R50 version

  1. Remove inner fender from the Drivers side. There are a few plastic clips and plastic screws.
  2. Remove the 3 10mm bolts that hold the huge plastic resonator to the inner fender.
  3. Disconnect the air temp sensor from box.
  4. Remove the box from vehicle.
  5. Drill holes all around box. Approx 20 holes.
  6. Reinstall box and reconnect air temp sensor.

 

Questions ??? My email is up top on the menu.