AE92 Cold Air Intake
I made a cold air induction system for the 20V in my AE92 SX that relocated the air filter down into the cavity inside the inner guard for about $21~$22 (plus the cost of the filter – which you already have) – I wouldn’t call that expensive.
Bits you need
I got a 1 foot long piece of 3inch exhaust tube from a local muffler place which was an off-cut (this was given to me for FREE) and a piece of 5mm plate steel approx 4 inches wide (another FREEBIE off-cut from a local welding place) and a piece of Ag pipe / Plastic tube from a place in Smithfield (can find their name again if you’re interested) which was a bit over a meter long (which cost $21~$22) plus the filter which you already have. NOTE for the filter to fit in the space I’m talking about it can’t be any longer than about 7inches long (K&N part number KN-9030 is spot on).
How to make it
If you look down between the battery and the inner guard there is a hole which has a black plastic tube poking through it, that’s actually a plastic box which is mounted under the guard and is pretty much redundant once you fit a K&N anyway so take off the plastic inner guard up under the wheel arch and then remove this box.
Cut a piece of exhaust tube about 3 inches long and two pieces of the plate steel about 1 inch wide * 1 1/2 inches long.
IF you have a bench grinder grind one end of each of these pieces of steel plate so that it’s rounded which will make it easier to weld to the exhaust tube. The tube which goes through the hole has to be angled forward slightly so when you grind these pieces of steel plate try and grind them at a slight angle.
Using a grinding stone bit for a drill (or better still I had a proper metal cutting tool for the drill) enlarge the hole in the inner guard so the exhaust tube fits through it – go SLIGHTLY larger so the tube can be angled forward.
If you look at the hole the tube has to go through there are two bolts either side of it – One holds the guard brace in place and I dunno what the other is for but remove both bolts (You’ll need to find slightly longer bolts to go in their place with the same thread).
Do a dummy fit by putting the exhaust tube through the hole, fitting the filter on the other side and then place the two pieces of plate (1 inch * 1 1/2 inch) either side of the exhaust tube so that they each cover one of those bolt holes and sit against the exhaust tube where they will end up being welded. Mark the outline of the pieces of plate against the tube and then pull it all out and weld them onto the tube.
Refit the whole thing and now mark out and drill the bolt holes.
Paint it if you like – I did to stop rust, then fit it.
The Ag pipe joins the bracket you made to the throttle body. I used 3 inch pipe coz I also made an adapter to go onto the 20V’s AFM which made it easier to select the size of Ag pipe I used. Obviously select a suitably sized exhaust tube and Ag pipe to suit the size of your throttle body, the inlet diameter of your filter. It all sounds long winded and complicated when you read all the BS above but it really only took a couple of hours to knock up and works very well. I also got some more Ag pipe and ran it from the hole in the front bumper and aimed it at the filter with some flyscreen mesh tied over each end. I haven’t had too many problems with water getting splashed into it from the wheels coz I taped up any gaps in the plastic inner guard for a better seal and unless you fully submersed the whole front end in water I don’t think a bit of water splashed in around the filter would hurt anyway coz the filter is aimed pretty much straight down so the water won’t get far. When I get around to it I’ll make up a fibreglass mould of the inner guard to properly seal the filter in.