Quote:
Originally Posted by Mountain
I've done this already and there isn't really more "whine" but there is more intake air noise. More air-rush type of noise, like a "whoosh".
I think those fins in the airbox serve several purposes: NVH attenuators (subjective NVH criteria based on some kind of consumer survey/trail and management team acceptance), air flow directors (keep in mind the various angles the air has to go through to get to the intake pipe and turbulent affects), and airbox structural stiffness modifiers.
I think that some of the vanes in the hat of the airbox should probably stay there, but I am not sure which ones. I can tell you, in monitoring MAF, going between the factory hat and a modified version where I did basically what you did, MAF went down... But... but, take that with a grain of salt because I only did some quick idle and street cruise speed data comparison.
Now, will a combination with the entire airbox being void of the vanes prove to be the best setup for power? I have no clue. My point is, those vanes do something. GM obviously spent time screwing with them in some sort of balancing effect. Messing with them, it's difficult to know if you're making things worse or better unless you play around with the combinations [between vanes being there and not and being there, or not, in the hat or bottom or both].
Personally, after seeing that MAF seemed to go down in messing with the airbox hat, by removing all the vanes, I left the factory, unmolested airbox hat on and just used a modified bottom box. In the bottom box, I removed the vanes at the inlet entry, with a few other vanes removed that looked like they could only impede flow into the airbox and up into the airbox hat/towards the MAF inlet. I chose this based on people's testing of cutting out the bottom box and basic understanding of airflow, having some experience on a flow bench, and targeting a select area that I felt confident would be something of an improvement. I did see a small MAF gain with this over the unmolested factory airbox - I can't remember how much though.
Note: I forgot to mention... I used waterflow to try and understand what air would potentially be doing in the airbox - I used spray from my garden hose, with an adjustable nozzle, to get somewhat of a visible way to see what I was messing with.
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I still have my "unmolested" airbox. That's a good thought, I'll test with the stock lid vs "de-vaned" lid. The top lid did seem to have more effective "vanes" in it with that weird glued in cloth piece.
Granted none of this will matter without dyno testing. I plan to go to CSP for dyno tuning at some point, but I'm holding off till I have more parts; LT2 intake, 95mm tb, CSP longtube headers, you know, the basics.
Manufacturers have to follow some ridiculous rules in their design; I'd really like to see intake designs in Solidworks to show the fluid dynamics simulations.