~$10 Intake Mod

[scotty nm35]

Very nice Cam, I love the way you spread the standard intake apart.

How big can you go on the pipe?

[iamhe77]

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!

Edited July 30, 2009 by iamhe77

[zei20l]

nice work cam!!

ill attempt this in a few weeks i think!

[andy65b]

Don't forget Cam, for an extra $15 you can make your own Power Duct with not hot air from the motor getting in.

Looks good what you have done.

[iamhe77]

Very nice Cam, I love the way you spread the standard intake apart.

How big can you go on the pipe?

LOL... I have heard that before

The tube is 40mm, but there is a ton of room there.

I will probably be looking at 50mm or 65mm pond hose over the weekend, whichever fits on the outside of the airbox inlet so I can clamp it.

[iamhe77]

Don't forget Cam, for an extra $15 you can make your own Power Duct with not hot air from the motor getting in.

Looks good what you have done.

$15!!! Who do you think I am? Paul Allen?? Jeez man...

Have thought about the powerduct or making one of my own, as you did, but never really got around to doing it (too lazy).

Will be considered this weekend. Doubt it will end up as tidy as yours though mate.

[pixel8r]

How does this affect low-end performance? Some people have mentioned that the powerduct actually loses a little low-end performance (but has gains at the top end). I'm a little hesitant to experiment with opening that panel on the airbox for this reason.

Interested to know what results you have now with this method...I would've thought more air would mean more response all the way through but feedback from people who have installed the powerduct seem to indicate otherwise. Is it any different with opening the main intake more?

[iamhe77]

UPDATE!

was just emailed this new mod that is next in line for those wanting performance on a budget!

[zei20l]

you cant ignore the results!!!

[iamhe77]

How does this affect low-end performance? Some people have mentioned that the powerduct actually loses a little low-end performance (but has gains at the top end). I'm a little hesitant to experiment with opening that panel on the airbox for this reason.

Interested to know what results you have now with this method...I would've thought more air would mean more response all the way through but feedback from people who have installed the powerduct seem to indicate otherwise. Is it any different with opening the main intake more?

Maybe have lost a tiny, tiny bit of free revving over 5000rpm. When I had the airbox panel off, the car revved up to redline effortlessly.

Now, if you concentrate on it, you can tell it takes a touch longer to reach redline... but yes, it does feel a bit stronger (but much more "together") in up to 5k.

hmm, will see if a larger diameter tube will make a difference above 5k. If not, Imay have to make an "Andy Powerduct" this weekend and see if I can have the best of both worlds.

Edited July 31, 2009 by iamhe77

[zei20l]

i might remove that scoop completely and duct in some more from the front using that intake to the airbox. and then also use your mod too. cant help opening it up some more!

[iamhe77]

i might remove that scoop completely and duct in some more from the front using that intake to the airbox. and then also use your mod too. cant help opening it up some more!

Dunno how much more air you would get in via a tube than the funnel gets into the airbox.

You could try 76mm flexible intake tubing, but you still have to avoid the engine fan/fan shroud when looping it back the to airbox.

[iamhe77]

Bit late with this, but I changed the 40mm tube for 50mm of the same tube.

No noticeable difference in performance... but a definite difference in install effort!

THIS is the pond hose that I used due to the smooth slippery inner wall (thus less drag/turbulence).

Well, so say it put up a fight is an understatement!

Firstly it was clamped to the outside of the connecting point on the bottom of the airbox (after some shaving), and then clamped to the outside of the CAI funnel, which was fine.

Finding the optimum length of 50mm hose which would allow me to place the funnel in the gab in the front bar WITHOUT popping the damn airbox out of it's mounts was another thing altogether.

Even when I cut the hose to the right length, it had to be wrestled into place.

Still pushes against the front bar!

My recommendation is to stick with 40mm if you are using that pond hose. No performance gains from 40mm to 50mm.

[chad bob]

I just pulled the cover off the airbox and removed the bonnet seal directly in fornt of the airbox, then I wound up the bonnet stopper just a bit.

With the cold air rushing in there at speed there shouldn't be any warm air getting in.

[datmoo]

So I thought I would have a bit of a play with my stock air box and intake to see how much cool air I could get in.

Liked the idea of opening up the snorkel but I just used one support on each side and a bit longer to open it up more.

Left the cover on where the "powerduct" would go for that stealth look.

Then I took to the inside of the air box with a die grinder to get rid of all the ribs and smooth it out for better flow (maybe).

Also removed that resonator chamber that just unclips and covered the opening with some aluminium sheet and some self adhesive foam.

Cut a 76mm (3") hole in the bottom.

Got some 76mm flexible tube from Clarke Rubber and just managed to squeeze it down to the lower bumper.

It wedges in against the bumper quite well (didn't use any cable ties) and is far enough back that it hopefully won't catch too much water or bugs.

Finally, I removed that hard plastic tube from the intake pipe and got a Turbosmart 38mm BOV plug which is actually a bit small and nearly fell through!

I have since found a 44mm blanking plug from eBay and it fits much better (put the old hose clamp back on too).

Results? Not so much down low but definite improvement in mid to high revs. Lower rpm (50ish) at idle too but not to the point where it's going to stall.

Loving the increase in induction noise/turbo whistle (sounds like an F1 car, small capacity V6 turbo, screeching tyres, sideways action, I think the new F1 cars are all good!)

Now for an exhaust to make use of all this extra air!