quick CAI question
 

on an S4 i have heard that the MAF needs to remain level when putting in an aftermarket intake, so I was wondering if it would be better to run the intake out so its a real COLD AIR intake and just like put an AEM bypass on it, or to build an aluminum box and keep the filter in there. Also, is it possible to swap the MAF with an S5 unit so it doesnt have to stay level?

I don't think the swap is a direct swap, but the S4 one does have to be level or you'll lean out I think. A true cold air would be the best way to go.

I've never heard of that, although I'm new to S4's as well....Can you explain why the MAF needs to stay level?

well the s4 air flow meter, is a flapper design, theres a giant metal door that gets pushed open when air is sucked into the engine, farther its pushed open the more air that is flowing.

when it is not level, or well turned sideways, gravity is pushing/pulling on the door, which will throw off the air flow level slightly, as the door will either open to easily or not open easy enough, depending on whcih way you turn it sideways....

So the flapper will work inside....

Good to know, thanks!

So swapping MAF's is a matter of just what, rewiring the S5 unit? Would the S5 unit give me accurate readings?

thers no need to do the extra work ... just mount your maf somewhere level (beside the strut tower is a common spot) there is even threaded holes to mount a bracket. after you've done that re-route the piping to where you want ... imo building a box is a good way to go ... the filter is protected from heat AND dust and the gains are going to be so similiar you wont be able to tell the diff between it and a real CAI .... this is assuming you do it properly and take your time

The CAI box would be simple to make if you're handy at all... : ) Just aluminum and some weather stipping to make it clean and flush. If not, several companies already have a pre-fabbed CAI kit available. Here's one at http://www.mariahmotorsports.com/ Look for it in the Products section; then Engine section. Search threads on here as well.

That mariah heat shield is expensive. If you're looking for a good heat shield check out VinSpeeds. I still think $60 is pricey but it's cheaper than mariahs.

No, no advantage whatsoever.