Changing Air Box R51 Pathfinder / Nissan Navara

Posted by Kevin Svoboda on


This Mod Is Not For Everyone and Requires Regular Maintenance and Checking.

To start off with this is a pretty straight forward but very daunting modification to do, from the research I’ve done the pre update models are easier to do as the air box maf sensor tube is unobstructed and not horribly connected to the air box. In saying that quite an easy job depending on skill level Allow 1-2 hours. 

Parts Required

1. Air Box (Can either go genuine Saas or Knock off eBay - I went EBay due to my research of them being the same unit just not branded - Slightly different Pod in the EBay Unit but it works the Same) Look Up Carbon Air Box EBay and they came up very quickly.

                Saas Unit                                           EBay Unit 


2. Some Sort of Adaptor From Air Box to Maf Sensor Tube (I used a Cv Boot and it work very well as i stretched the tube over the EBay air box and the bigger end Clamped Down to the Maf Sensor Tube) A 3’’ to 3’’ straight adaptor should work well. Measure this and check as this may change model to model.

3. Sika Flex (this is optional for the Joins in the air box ect) I personally haven’t used any but i may do in the future after further Testing.

Tool Required 

1. Basic Socket Set

2. Basic Spanner Set

3. Basic Screwdrivers  

4. Dremel With Cutting and Sanding Wheels 


Lets Do This 

1. Open your bonnet and inspect Air box as bellow. It is advised to do this mod before your snorkel is installed (although you can do this mod without a snorkel). Your new box will need modifying to suit your snorkel, depending on model of vehicle this will determine what is required. For me I will be replacing the whole inner duct of the snorkel as I wasn’t happy with it but I will update this how to when I do so. I cut my inner duct to the snorkel as  I knew i was changing it but if your reusing the ducting remove inner guard and remove this way. 

2. Remove Clamp From air box 

3. Unplug Maf Sensor and Remove. Place this on a clean dry clothe to one side away from were you are working, you do not want any contaminates damaging the sensitive item. This is easily removed with a screw driver. 

4. Remove air box lid as pictured below, there are 4 clips on the air box that connect it to the base, these are very simple to remove and are located on each corner of the lid. Remove air filter and discard. 


5. At this time if you have an update model I would make a point of looking at the lid and inspecting what needs to be cut. This is the hardest part of the hole install if you have an update model. Alternatively buy a older style Navara D40 or R51 air box and the cut is straight forward and simple. 

6. The bottom of the air box is held on by 3 10mm Bolts. Two ar very easy to access the other is quite difficult (this could be different on the earlier models) I suggest and recommend gently pulling the air box up over the lower harder to access bolt and removing after the air box is out. Your now have and empty spot were your old air box used to be. 

Area Clear of Air Box Below 

7. Next Step is getting your new air box ready. The end going to the snorkel or sitting in your air ram location in your guard may differ from setup to setup but for now the below is what I’ve done. Using Clamps supplied connect the appropriate joiner. I choose to run a cv boot but you can run a 3’’ to 3’’ joiner or whatever size you have measured. At this point make sure the pod filter is in the correct layout with the cone facing the outlet (non turbo side) and the whole facing the turbo. 

8. At this point fit the air box to the car. I mounted mine so it sat fairly close to the ram inlet in the guard (actually sits inside the snorkel air duct) leave enough distance so the it doesn’t rub or vibrate on the inner guard. You will have to determine the location of the air box and bend the bracket into shape but this is completely up to you how this sits. You want it to sit about the distance in the photo below away from the stock air tube to the turbo. I had to cut the little hook of the bracket and used a m10 with a washer to mount it to the inner fender. 


Picture Below is of the Air Box to the snorkel air duct (currently sitting there but will be soon changed and fully sealed)

9. The next step I’ve left till last as if you did as i did and used the factory air box lid and maf Sensor tube out of you Update model its quite painful and time consuming to do. Its 100% achievable though and if you don’t have the funds or cant find the old lid of another car just mod yours. Its pretty easy to cut using ur dremel and obvious were to cut but your lid will end up looking like the below picture. You can not turn back if you cut this lid so make sure your happy to do this. If you have an older model it is as simple as cutting the air box section off, using your dremel with the sanding attachment and debur the cut and your ready to insert the modified Maf section into the spot between the new air box and turbo pipe. If your using the updated pipe see step 10.  

10. The below picture is the end result. To achieve this you will need to spend quite abit of time cutting and sanding the tube to get it a nice even consistency across the pipe. I sanded down the step up and step down to be level (you will understand this when you do it) and debured the cuts ect with the dremel then your sand paper to tidy it up after. Take your time with all the cuts, do not rush and you wont have a problem. 

Another Angle of the modded Maf Tube 

11. Insert modified maf tube between air box and factory turbo pipe. Clamp both down and check all connections. Reinsert Maf Sensor, ensuring the open end of the Sensor is facing the air inlet side. Start Vehicle to hear the sweet tone of your intake and your done. All going well you shouldn’t have any engine lights ect. 

Hope this how to helped - these how to do instructional step by steps are for guidance only, i will not be held responsible if for any reason by following these steps you brake or damage any part or parts of or in your vehicle. If you have any questions feel free to comment or send me a pm on my facebook page. 

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