Engines need air, fuel, and spark in order to make power. Increase fuel or air, and you can make more power. One of the easiest ways to increase power is to remove restrictions in the air flowing into the engine. Most cars these days use plastic tubes and large flat filters in a big silencer box. Incoming air has to make several 90-degree or sharper bends in short distances, which creates a huge bottleneck. Air does not like to make sharp turns, so when it has to do so, the air speed slows down and starts to churn. This churning reduces the overall volume of air that gets through.
Part of the reason that the factory uses this design is because it is quiet. The air intake of the engine can be fairly loud, after all an engine is nothing but a giant air pump. Reducing the volume of the air intake is an important component for most OEM manufacturers, but it comes at the cost of horsepower. You can increase the flow of the air going to the engine by swapping out the paper filter in the stock air box for a high-flow, oil-free filter element from K&N Filters, but if you really want to open things up, replacing that restrictive air box is the next step.
While there are super-cheap versions floating around the internet, you really should stay away from the cheapos and go with a quality part that has been tested and designed specifically for your vehicle. For our 2013 Suburban, we selected a K&N Blackhawk system. This kit includes a large cone-style oil-free Dryflow filter, a fabricated metal insulation shield, and a large diameter mandrel-bent aluminum intake tube that reduces flow restrictions. The filter is washable and should last the life of the vehicle, in fact, K&N gives them a 1,000,000 mile warranty. The filter can go 100,000 miles between cleanings. Each system comes with a 10-year 1-million mile warranty.
The intake system replaces the restrictive air box with a sheet metal shield that secures the high-flow element intake tube. The K&N Blackhawk kits use an aluminum tube, which has mandrel-bends so smooth flow, no corrugated bellows or flimsy plastic tubing to cause issues. The stock MAF sensor is also retained so there is no computer tuning required. It really is just install and drive.
Installing the kit is not complicated, but it does take some time. A typical install should take about 90-minutes, mostly because there is a lot to remove from the vehicle. Most of the installation is done with hand tools. The process includes removing the factory airbox, intake tube, MAF (Mass Air Flow sensor), and PCV tube.
Besides the increased performance (the Suburban kit touts a 12 hp increase), the sound of the engine at wide open throttle is pretty darn amazing. The car no longer sounds like a pedestrian people mover, it sounds like a hot rod when you stomp the go-pedal. The intake system looks pretty dang cool too. No more filters to replace, improved horsepower and torque, killer sound at WOT while regular cruising is quiet like stock, what is not to like?