Cold-air induction-or "CAI"-kits are typically among the first things enthusiasts add to their Corvette. And why not? They're affordable, generally pretty easy to install, and offer a real-world performance gain. CAIs for the C6 come in three general styles: open element, cold air, and ram air.
The open-element filters are installed in place of the factory air cleaner and draw ambient air from the engine compartment in the same fashion as the stock unit. They usually employ a large, open-element filter with some sort of cotton-gauze media and nix the flow-restricting shroud. These tend to be slightly less expensive than the other systems because they're smaller and less complex. Installation is a snap because they require no cutting or modification of the car.
Cold-air systems draw outside air from the cavity in front of the radiator and air-conditioning condenser. From a performance standpoint, this type of system is preferable to an open-element filter, as it delivers cooler outside air to the engine rather than relying on the hot air found underhood. Most cold-air systems use a panel-style filter and a housing mounted to the radiator shroud.
A ram-air system, such as VaraRam's two-piece Snake Charmer, takes the cold-air concept one step further. Instead of simply drawing air from beneath the radiator shroud, the VR's lower housing employs a forward-facing scoop situated directly in the path of oncoming airflow, behind the grille.
The downside is that ram-air systems require a hole to be cut in the radiator shroud in order to access that outside air. In itself, this is not a big deal, but many would-be modifiers balk at the notion of cutting holes in their brand-new car. If that's you, this is not your intake.
There are a myriad of manufacturers building these systems, and some of them make pretty bold performance claims. For instance, VR says the Snake Charmer will add 40 or more horsepower. When pressed, company reps quickly explain that this claim is only valid for speeds of over 100 mph, when air is actually being forced into the scoop. (In support of that notion, VR says the system will add 8-10 mph to the C6's 186-mph top speed, a claim we were unable to verify without risking long-term incarceration.)
VR also claims that, at speed, the Snake Charmer creates a positive pressure (similar to a mild supercharging effect) in the intake system. But try as I might, I was unable to verify this through the use of a boost gauge or by monitoring the car's MAP sensor. Perhaps the effect is too subtle to be measured with conventional instrumentation.
Typically, the power gain from a ram-air system such as this one will be fairly modest on a stationary dyno. There, the stock air cleaner does a relatively good job of supplying air to the hard-working LS2. In fact, VaraRam requested that we conduct our performance evaluation on the drag strip, as that is where the performance gains purportedly become clear.
VaraRam offers two optional items for the Snake Charmer. The first is a throttle body spacer that effectively increases the intake manifold's plenum volume and ought to deliver a small power increase. This part was unavailable for our test, however, so I can't comment on its effectiveness.
Also offered is a pre-cut radiator shroud, which I recommend you forego. It's almost guaranteed to double the install time, because removing the shroud is a royal pain, involving partial disassembly of the car's lower valance. Do yourself a favor and carefully cut your existing shroud. If you do wish to replace it in the future, new ones are as close as your favorite GM parts house for about $40.