cold air intake for the budget conscious.

[CMF_mipcar]

How budget? Well essentially nothing, zilch, free.
Mind you it's not high tech and not the full "real deal" with a funnel to force air in, although that will come later.

I had at home some 50mm non-slotted flexible aggy/drain pipe.With this pipe I had a connector and I found that with a bit of grease and the judicious use of a heat gun I was able to make the connector soft enough to fit over the flange of the standard Nissan airbox. Once cool again it's an interference fit.

Then simply a matter of cutting as much pipe as needed and feeding it along essentially the same route as the old Nissan pipe ran. However the aggy pipe is larger and with a constant diameter. All I need now is to design a funnel/scoop arrangement to slide down behind the left hand headlight.

Total time to do the job, 10 minutes. I've retained the standard Nissan airbox which "imho" is satisfactory, wont affect any sensors and I can keep a standard filter.

Have to test drive it yet to see if there is any "seat of the pants" improvement.

If it does not work it's no big deal to go back to original.

Mychael

 

[CMF_mipcar]

Well I took the car for a test run.It's all purely subjective without doing a proper before and after on a dyno.
Certainly no loss in performance, induction noise the same (which suits me). It felt like it was pulling a bit better down low and a slightly snappier throttle response from low revs.

Mychael

 

[CMF_Dark Side]

Way to go Mike. With 2 Micras in your garage you will not know which way to turn.Your weekends are now full. Hope you have an understanding other half.Stick a pod filter on the end of the cold air intake and throw away the Micra filter/ filter box.

 

[CMF_mipcar]

I'm trying to think back to when we had the big Micra rally here in Melbourne and we all went to the dyno place.
If I recall correctly one member tried his car with different configurations.
One was micra airbox with Nissan paper panel filter
Second was same airbox with KYB replacement panel filter.

There was no measurable difference between the two.

Then another member or maybe the same tried it without an element in the filter box at all and performance went down.

My opinion for whats it's worth is that the relativly large volumetric capacity of the Nissan airbox allows the engine a "gulp" of ready air when you first open the throttle.

Mike

 

[CMF_Yom]

Under constant acceleration it would not make much difference.

However when you back off and there's vacuum in the filtered side of the airbox the air will naturally move through the filter to equalise air pressure on the other side of the airbox. I cant remember the maths for it but apparently there's an amount of prefiltered air you must have for optimal initial throttle response. Manufacturers seem to go with an airbox size that relates to the capacity of the motor, rather than the power output.

Unless you've got a really good exhaust system I doubt the differences between pod filter and a properly modded stock airbox would be much. We're still restricted by that tiny little throttle butterfly.

Cheers

 

[CMF_deNs]

Well I did notice a difference moving from the stock tubing to the setup that cisco used to have (and I don't need you commenting on it Yom).

Uphill climbs pulling in 3rd or 4th was hugely improved. Didn't have to drop down gears on inclines where I normally would have - it just keeps pulling.

Dunno how effective it's going to be behind the headlight though. I never understood why it was put there when there were better places to pick up from.

---dens

 

[CMF_mipcar]

For me retaining the headlight spot was simply for "quick and easy". It will still allow me to make an extension down lower behind the bumper assembly. Keeping the intake hose on that side puts it the furthest away from heat sources.Also good for insurance purposes as still standard airbox.
I have Hurricane 4-2-1 headers with 2" system. I noticed a big change when I fitted those yrs ago.

My "cheap tube" air intake setup has allowed a larger constant diameter feed to the airbox but I cannot maintain the 2" pipe size and fit it down past the headlight, requires an oval shape pipe to get past things.

The other thing to remember is that the next best thing to a positive pressure airflow (such as vent/funnel) into the airstream is to be able to draw air from non-turbulent air. My pipe sits directly over the space leading down behind the headlight into the area behind the bumper.
This should in theory be an area of stable air which should still be colder then the engine bay air.
I proved with my car that fitting vents in the bonnet lowered running temps by pulling out the hot dead air that gets trapped inside.
So I reckon there should a cold draught coming up from under the car.

Mychael

 

[CMF_evade]

PVC plumming for the win!

deNs WROTE:

"Well I did notice a difference moving from the stock tubing to the setup that cisco used to have (and I don't need you commenting on it Yom).

Uphill climbs pulling in 3rd or 4th was hugely improved. Didn't have to drop down gears on inclines where I normally would have - it just keeps pulling.

Dunno how effective it's going to be behind the headlight though. I never understood why it was put there when there were better places to pick up from.

---dens