Cold Air Intake

[Mikewire]

It really has nothing to do with turbo or NA - the thought is the same no matter (however a turbo does heat up hotter and faster). You should keep the cold air coming into your intake cold. As your engine heats up the engine bay and the metal in and around it you will soon just be sucking hot air straight into the engine, and hot air is less dense than cold air so that will decrease engine performance. So, like I said earlier, you need to find a way to partition or vent in the cold air, otherwise the intake and your IC are doing no good.

[Dubber]

When you mean partition you are talking about a SRI with a heatshield correct? and when you mean vent, you are talking about a true cold air that draws from the fender correct?
And I agree with ya Mike - I think you said it well

[ryan's05gli]

yes you guys are correct that the cold air will still bring in cold air. but when it goes through the turbo and gets heated up and like stated before your gains will be marginalized especially if your pushing it through a front mount or any decent intercooler. all i'm saying is that $150 minimum for a new cold air intake seems steep when in all actuality it is only going to gain you 1-2 whp max. if you can find one for 30 bucks or so then go for it. but i'm guessing the guys getting rid of it for 30 bucks realized that most people don't want them because they render no real gains on a turbo'd car. a short ram will outflow it and like previously mentioned, putting a vent in your fender or hood over the intake will both cool the intake while providing maximized flow.

and the reason you can see a huge gain from a cold air intake on a NA car is because all that cool air is going straight from the filter and getting thrown almost straight into the combustion chamber. it has no turbo to go through to heat it up. you will see gains for 10-15 hp with a NA engine depending on it's size where you will only see a very small amount on a turbo car (1-2 hp)

[ryan's05gli]

http://forums.vwvortex.com/zerothread?id=3579394

here is a thread where they took actual MAF reading testing the different intakes. turns out the stock air box with some cheap (free) mods will outflow most aftermarket CAI and SRI intakes. it even has a pretty graph

essentially what your gaining from an aftermarket intake is the woosh sound of the diverter valve dumping.