And our '00 Burb is still using the stock airbox and duct, no aftermarket tube and cone filter for us
Thank you for that.
A couple stories of how the system came to be:
The system was capacitized for the "big engines" of the day: the L18 8.1L large block and the 6.2L diesel.
Flow restriction specification (from GM Powertrain) was a ridiculous 1" Hg restriction at "max flow", from the ambient air inlet to the intake valve. Since that was essentially unachievable, and since we (the vehicle side) cannot control what goes on inside the engine, we negotiated that back to "from ambient air inlet to the throttle body inlet", which was more in line with what we could control. Max flow was established as 272 g/s.
Since the system was designed around the biggest engines, that means it was over achieving for all the smaller engines (4.3L, 4.8L @ 212 g/s, 5.3L @ 230 g/s and 6.0L @ 242 g/s). So, from a restriction standpoint, you should not see any improvement in going to an aftermarket air induction system.
From a cold air standpoint - the gains from air inlet temperature reduction are enough to offset any increase in flow restriction, but we also had stringent air inlet temperature increase requirements that were met. The fender inlet shields the intake from hot underhood air, while also preventing water ingestion (those two requirements are typically at odds with one another).
Lastly, the tuning devices that you see: quarter wave tuners and helmholz resonators, are not in the flow stream and do not affect restriction. They are tuned to attentuate specfic targeted frequencies, and absorb the energy pulses as they radiate backwards out of the throttle body.
Bottom line - the production system was designed by a "hot rodder" and was consciously packaged and components chosen to minimize flow restriction; an aftermarket intake is incrementally directionally correct in some aspects, but probably not measureable.
K
