... But compared to most so called CAI, that place exposed filter in hot engine bay, behind radiator, and are really more of a hot air intake, the oem box is indeed superior.

IMO a true CAI best feature is better throttle response. Just like area under the curve is often more important (street) than peak hp. Often a true CAI won't have much impact on peak hp (at least, its difficult to measure, as dyno, with fan blowing, doesn't necessarily replicate real world driving experience).

A CAI that places filter down in lower fender area brings some compromises that can be awkward for some. The potential for water injestion, the difficulty evaluating filter condition and changing it, etc. Some won't mind these at all, some will find them showstoppers.

Insulating stock intake and adding a dusct that draws from in front of radiator can bring some of the true CAI benefits. A reasonable alternative to those that find true CAI compromises a showstopper.

 

Syncmaster you are 100% correct. BUT you can make the stock intake draw cold air as well. I never see more than 5c above ambient with my stock airbox (drawing air from the fender area and with carbon cooling plate attaching to the stock inlet).

 

I love my modified air box. I am running a Spoon Snorkel, K&N Filter with the mid wall of the OEM box cut out and the resonator blocked off. I also replaced with the stock arm with a Samco hose. I absolutely love the setup. The car power wise feels excellent especially at speeds but the best part is the razor sharp throttle response.

 

How does gutting the intake box increase power?

 

I would say the power gains are minimal, at best. I think with the some of the mods discussed above, you can lower the IATs and increase throttle response which I think is what we all care about (at least the NA guys).

 

Gutting airbox is more of a sound mod.

Adding a duct from that large opening in fender near passenger sideof stock airboxis an excellent mod. Cut 3" round hole in side of airbox, mount a 3" bulkhead duct flange, attach 3" hose routed into opening.

For greater effect, route that hose through inner fender area, add a 3" hole in plastic bulkhead that separates area behind grill from inner fender area, attach to scoop mounted in grill area. I think that is what photo of grill area in post above is all about.

You'll get fresh, cold air piped into stock airbox. It might actually be agood idea to block off stock rectangular intake at that point, to avoid flowing OUT one of the two possible intake paths...

 

Agreed - I also have used a modified stock box in the manner suggested in this thread with decent results. However, with that option you don't see the power benefit that a long-tube intake provides. Again... this is proven (not by me, but others have dynode them with great success over other options, including modified stock boxes). Honestly its not going to be THAT much of a difference either way. The point I was trying to make is that the stock airbus isn't that good in comparison to other readily available options (or simple modifications). I have no idea why people think otherwise.

 

The long tube CAI benefits power both by drawing cold air, as well as by having a long tube. My understanding is peak power is improved more from the long tube than from the cold air (but cold air provides greatly improved throttle response, so its win-win).

But its not for everyone. Its not inexpensive, its not convenient to replace filter, its not risk free.

So a modified stock air box that is able to draw cold air gets most of the throttle response benefit, but none of the long tube peak hp benefits.

 

Long tube benefits are only seen at about 3500ish rpm with the infamous hump. I can't see any difference at high rpm when comparing the best intakes out there with some modified airboxes (especially the ones that have the dual inlet modifications, drawing air from the fender). Vacuum at high rpm is also the same (if not less with modified airbox) than most CAIs I've seen. The long tubes are becoming restriction themselves unless really big in diameter (3" or more but then you lo0se velocity). And I am talking standard paper filter, not even a high flow replacement!

 

All good points guys - I certainly agree. You really can't go wrong either way. The modded box or a long tube ARE better than a purely stock box. For me though... I prefer the long tube style even if the only "benefit" over a modded box is the sound. Love the sound. Always have since my days driving around swapped EG hatches.