Right.
So I got a bit sick of looking at that damn open airbox in my M35, no doubt sucking in warm air from the engine bay and I refuse to shell out $180 to Nissan for a Powerduct.
I decided to see how a secondary CAI would go on with a closed up airbox compared with the open airbox panel and stock air intake I was running.
While I was at it, I decided that enough was enough with the "sucked in" opening to the OE intake funnel.
As you can see below, the airbox panel is removed (duh!) and the right side of the air funnel has almost been sucked closed.
I was toying with the idea of an aluminium airbox with pod for some time, but decided to go this route first as it would cost very little if there was no improvement.
First up, the factory air intake funnel.
I found these some plastic wall lugs in my tool box (similar to THESE).
Drilled 3 holes in the bottom of the intake funnel, painted the lugs black and gently screwed a screw into each of them from underneath.
It stretched open the right side of the funnel quite a bit, yet the bonnet causes no damage to it at all.
end result looks like this
Next, I cut out the inside of the "drain hole area" of the bottom of the airbox (obvious when you look) and stuffed one end of 40mm flexible pond hose into it.
I went with 40mm as it was all I had lying around, but you can buy it by the metre from any Reece Irrigation store (probably other Irrigation or Pool shop would stock it too).
I used pond hose as the inside wall is quite flat and very slippery.
I bought an 80/50mm DWV reducer from Reece (or Bunnings or Mitre10... whatever) for a couple of bux, sprayed it with a matt black primer so it dried faster and stuffed the other end of the hose into the 50mm end to make the funnel.
I then just used a large cable-tie on one of the rear holes in the reo bar to hold it in position nice and tightly.
This is all you can see from the outside
Surprisingly, it has made a HUUUUGE difference. Car feels a lot more solid and I have no hesitation accellerating a bit harder now (no stupid WWWwwwo sound. Some of you M35 guys know what I mean). Top end of the rev range is fine as well.
If I put my hand in front of the funnel, I can feel the air getting gently sucked in when the car is idling. Can only be a good thing.
Takes about 45 mins all up if you let the primer dry. Far too easy.
It is a quick, easy mod that is quite beneficial, it would seem. A lot cheaper than a Powerduct as well.
Anyway, there you go!