Installed the PDI airbox today. It's well-built, 4" in, 4" out and uses a 200 series filter.
There's a drain at the bottom that uses a Toyota duckbill style valve as well (I believe these came stock on FJ Cruisers, 105s and VDJ79s.. don't quote me on that. Bought this separately in the US.)
First step was to remove the factory airbox. I also removed the inner fender intake since I'll be adding a snorkel soon.
To remove the two piece fender intake, there are 3x 10mm bolts. Undo the first one toward the front and you can move the front intake section out of the way in the fender.
Then remove the cruise control cover and you can access the two nuts for the rear intake section.
Both will slide right out. Rear:
Front:
Next you transfer the OEM rubber mounts and metal inserts from the old airbox to the PDI. Took me a second to figure it out but you just squish them in there
Then you figure out the piping from airbox to turbo -
I capped off the PCV inlet on the PDI pipe with a 5/8" coolant cap and OEM hose clamp.
Some messing around and cutting silicone to find the right length of each section and setup.
I initially tried to install the airbox with the battery installed on the RHS but there was no way to access one of the bolts connecting airbox to body. So I removed the battery and battery box.
With that done, it was no problem to install the airbox and get the piping all fitted up. I have the airbox inlet running directly into the fender right now until I get the snorkel installed.
The fit is extremely tight with the battery box. It just barely fits but that moves up designing a new battery tray up on my list of priorities.
All buttoned up:
I did run into one snag. Some of these HDJ81s with all the options have a steering box with a solenoid that tightens up/makes the steering more heavy at high speeds. The wire connecting the body harness to this solenoid can be seen here crossing directly underneath the airbox:
The plug was interfering with the PDI airbox so I unplugged it and figured i'd work it out later. I assumed it just wouldn't activate the heavy steering at high speeds but nope - it did the opposite. Now my steering is super heavy all the time. haha oops.
I'll have to get back in there and either unwrap the body harness to give me some more slack and reroute, or extend those two wires. Not sure yet.
I started it up and did a quick test run. I have a winding mountain road on a steep incline nearby that's my "test track." Goes from 5K feet to 6K feet over the course of 3 miles.
To be a little scientific, I drove this road before:
40° ambient temps, stock airbox, intercooler: foot down for almost 2 miles, at the end of a long straightaway, I saw 1300° F EGTs
After:
35° ambient, PDI airbox, intercooler: foot down at straightaway, 1200° F EGTs. Also I'm approaching the limits of my testing abilities there as this time I was almost 10 mph faster than before at that point. And as you know an 80 just isn't built for canyon carving hahah
I was impressed so far, feels like it spools up a little faster and it sounds good too. I'll repeat again with the snorkel.