Tadge for GM Corvette Engineering

The induction systems for the Stingray, Grand Sport and Z06 are essentially identical. ( thus can no way be degrading or preventing HP or torque output for the LT1)
The only difference is that the supercharged engine has an off-center location for the throttle body that necessitates a different plumbing geometry downstream of the filter.
Although one person speculates that we commonized the filter elements to save money, that is certainly not the case.
We engineer all Corvette intake systems for minimum restriction and to meet many other requirements that aftermarket companies do not.

We do not routinely test aftermarket induction systems or any other aftermarket parts for that matter.
We have our hands full designing, building and testing our production hardware.
Although simple in concept, induction systems play an important role in many vehicle performance areas.
Aside from the exhaust, there is no greater noise source on a performance vehicle.

Induction systems generally have many tuning elements that ensure the quality of the sound emanating from it are pleasing and harmonious with the exhaust note.
These tuning elements also dampen the sound energy to help with pass-by requirements.

Aftermarket companies don't have to worry about it, but as the OEM, we must guarantee that our products are quiet enough to be driven at full throttle by a microphone by the side of the road and meet certain decibel levels. There are pass-by laws in many states and pretty universal around the world.

Another important element in the induction system is the mass air flow sensor or MAF.
Engines can only run at their optimal efficiency if they have very precise data on the amount of air flowing into them.
Although most people think of air flow into an engine as fairly continuous, it really is not.
The opening and closing of valves and reciprocating nature of internal combustion engines means the air flow is really a series of pulses which make measuring the exact flow challenging.
Intake engineers spend a lot of time optimizing the system to get excellent signal quality out of the MAF.
In addition to efficiency, or fuel economy, the precise metering of air and fuel is directly correlated with tail pipe emissions, an area of extreme scrutiny by government agencies for we manufacturers.

There are some other areas of intake design that you might not think about right away such as water fording. We do tests where we drive the car at various speed through water troughs of depths between 2 and 12 inches.

Most customers would never dream of doing such a thing, and, although I don't recommend it, we take due care to make sure the engine does not ingest water.
In fact, as we get to the end of the trough, we go wide open throttle to maximize the suction into the engine.
In case anyone is puzzled about why this is important, when an engine ingests water into the cylinder, it can hydro-lock resulting in complete engine failure. Most customers would return to the dealer and ask for engine replacement under warranty.

This is one of the reasons installation of aftermarket intakes can void your powertrain warranty.
In addition to water fording we do validation testing for extreme rain, snow and dirty environments.

Besides needing to be fed dry air, the induction system needs access to cool ambient air.
This is why we breathe into a space behind the headlamp and under the right fender.
The air inside the engine compartment is generally much warmer and, even though a larger, lower restriction filter could be packaged there, the hot air ingestion outweighs the filter restriction in terms of real world performance.
Now some companies might make this choice and then optimize the dyno set up to minimize the effects such as running with the hood open or a strategically placed external fan.
I have no specific knowledge about how the aftermarket companies operate,
but I do know that dynos can be set up in many ways to demonstrate performance improvements that do not materialize in real-world driving.

The air filter itself is the focus of many discussions on low restriction.
Its job is to keep foreign material out of the engine.
Here again, there are many trade-off decisions balancing restriction with filter life (service interval) and filtration quality.
Sacrificing either of the latter two improve the former.
We tend to be conservative to make sure that our engines are very durable, so that does open up an opportunity for aftermarket system.

As with many of the questions, all vehicle design is a balance of trade-offs.
We do what is legal and right for the vast majority of customers.
Aftermarket companies offer products that strike a different balance that might appeal to some folks.
I am appreciative of this opportunity to explain some of the thought behind the decisions we make.