Air box CAI mod for my VY SS ute. (Cold Air Induction)

 or how I did it my way :-)

Okay, after much looking and reading and a couple of Jabs from an old friend, I have done the CHEAPEST mod ever to my SS ute. Yes the 'second hole in the air box' modification.

Having never had the top of my air box, I went in with just the help of the articles and threads on the www.ls1.com.au internet forum. Use the search function and lookup CAI [Cold Air Induction] on the forum, it makes interesting reading.

Being an asthmatic my self, I decided its the BIGGER is better principle for breathing, so I opted for a 70 mm PVC gutter pipe joiner to poke through the air box and the shroud behind the light.

DISCLAIMER: I am not saying this is the RIGHT way to do this or even the BEST way to make this change. All actions taken by you the reader are at YOUR own risk. This is simply a description of the changes I made to my own car (Holden VY series 1 SS ute).

Okay first thing is to get the top of the air cleaner box. On my VY (series 1) the coolant reservoir overhangs the top mount for the air cleaner under body, so that has to move at a later stage any way, so its easiest to do it now. Disconnect the coolant feed from the radiator at the plastic tank end, then you loose very little fluid.

Loosen the clamp around the MAF-AIRBOX rubber boot. Undo the three screw on the lid of the air box. Lift the lid up slowly while working the outlet of the box out of the MAF rubber boot. Once off remove the air clean element and keep both in a safe and dust free spot.

Mark the position of the lower air box to the position of the front shroud, so you can line them up while they are out of the car (essential to getting the holes in the right spots) You can see the RED marker pen I used on mine. Its an "AFTER" picture shown, as I did not take a pic early on with them all lined up ;-)

On the outside of the box there are two RIB's running down to the front mounting point for the air box. I chose to trim these back by 10 mm to allow the 70mm hole I wanted, see photo below. In this picture the hole has been cut with the biggest hole saw I had, from here on out its the small coping saw, knife and file to enlarge the hole. (hole shown is about 60 mm)

Now as you can see by the photo above, I did not realise that the screws stayed in the car and the rubber mounts pushed / pulled over the head of the bolts. So when it comes to pulling it out or putting it back in be firm but careful and the box will PULL OUT leaving the mounting studs in place.

Well this is the hole finished, the 70 mm (inside diameter) coupling is a snug fit in the second hole.

To locate the coupling and stop it slipping out, either into the air box or the shroud, I wound on 5 turns of insulation tape. Now the tape is placed towards one end of the coupling (not in the dead centre) so as to push more out towards the shroud side (front of the car). This leaves a nice protrusion into the air box and the same out of the air box shroud. After the 1st 5 turns of tape, I added some foam strip like they use to fill gaps around windows and doors. Its sticky on one side, anyway its not important what it is, just it provides some BULK for the next 5 turns of tape to cover it up. This makes a nice RIDGE on the coupling, which when its all assembled firmly holds the coupling from slipping out.

Next on the list is the air box shroud. When the air box hole was drilled the same hole needs to be marked on the shroud and cut to match. This is where that alignment mark on the two comes into play. Mount the shroud back on the air box and mark the hole.

The tube in the new hole needs to protrude forward more than back into the air box.

The shroud is shaped to fit the primary hole, trial assemble the air box and shroud a few times until you fully understand how it all goes together.

BEFORE you cut the air box hole, ensure your selected spot will align with the shape of the shroud. If it does not, you will have a fair old job ahead of you to seal it all.

Other side view, note how close together the holes are.

A close up of the inside of the air box once its back in the car (looking fwd) The added coupling protrudes the same amount that the original one does. Could not find a black connector at my local Mitre 10 ....

Put all back together, in the reverse order to taking it out :-) make sure there are NO left over plastic saw dust to get into the system. I brushed, washed and wiped all my air box components until they were spotlessly clean.

Well that's about it for me, it all seemed to go well on my VY ute (series 1) I am unsure how much of this is applicable to other models or series. No noticeable change to cabin noise, I did expect some more intake roar but nothing heard. 

(update on 13-Nov Took the car for a longer drive and can hear a nice little rasp from the intake now... so it can be heard)

This mod would have to be the cheapest change to my ute so far ($2.20) and it was fun to do. just me, the tools and some plastic to cut and hack !!!

If you have any comments, please email me and let me know if there are any errors or improvements I can make.

Peter aka VK8ZLX on the forum.