So I just did a tune up this yesterday and while I was picking up spark plugs I saw those prebuilt aluminum pipes for cold air intakes and I got to thinking. I don't have any problems with the stock airbox but I was wondering if I could get better airflow through a smooth tube. The stock unit has those accordion ridges which can't be good for airflow. Anyone tried changing the pipe from the MAF housing to the bipipe?

I know that even if it improves breathing the gains will be miniscule. I mostly am interested in swapping because that pipe drives be crazy when it needs to come off. I feel like a pipe connected with silicone hose and hose clamps would be much easier to remove. Thoughts?

 

The gains would be miniscule, as you already pointed out. While the ridges have an impact on the airflow, the size of the tube is such that that impact would be minimal in the flow volume and speed range experienced by your car, unless, of course, you have modified it to an extreme extent.

To make it easier to remove, change the spring clamps for worm gear clamps.

Bob

 

Does anyone know the volume of air and the speed at which it passes through the intake? I have been wondering how airflow dynamics differ between natural and forced induction. For instance, does resistance become less of a factor in turbo applications due to the air being forcefully compressed? Would smoothing the intake system in the 4.2 have larger benefits?

 

The airflow dynamics between NA and boosted is basically the same except boosted has two pumps moving the air while NA has only one. For high RPM applications, you want as smooth of airflow as possible. For idle and emmisions, you want roughness to get the air to tumble to mix the fuel.

Technically, resistance becomes higher with compressed air due to the increased density of the air but, practically, the pump overcomes this resistance and the total mass of air supplied to a cylinder is increased, so, resistance becomes less of a relative factor in boosted versus NA applications. That's why you can have extra tubing, extra bends and intercoolers and all that crap on a boosted application and still get more power.

And yes, smoothing the 4.2 will have more effect than smoothing a 2.7t.

Bob