[Wobble Goat]

I've seen people cut holes in the stock air box for more air. These people didn't insulate their holes from the engine bay so they essentially ruined a good CAI that comes from the factory.

The lower portion of the stock intake has a bunch of cross support plastic. Has anyone ever attempted to remove these air / sound obstructing pieces while keeping the rest of the box intact? Searching this forum only results in people cutting holes.


I prefer / enjoy DIY experiments over buying over-priced products.

I'm not knocking people's products. I think the Rotofab intake is fantastic, but $430+ for 3-5 rwhp, that's a tough pill to swallow.

[mano_camaro]

Originally Posted by Wobble Goat

I think the Rotofab intake is fantastic, but $430+ for 3-5 rwhp, that's a tough pill to swallow.

[parish8]

I cut a hole facing into the fender. It gained 3hp on the dyno with multiple before and after runs.

No idea if the temp of the air in the fender well when moving.

[s346k]

op: you're trying to split the hairs that have already been split once. i did a lot of testing my cut stock box against a dry rotofab. iats appeared unaffected across the board. basically i concluded that a rotofab was worth 0 over a cut stock box. at speed, on the dyno or otherwise. stock long block: the restriction in the intake system is not the air box, it is the throttle body. but truth be told, my e85/bolt on car saw very little peak power from adding a rf dry and 95 mm tb. but i do think those additions contributed to the preservation of peak power over 6k rpm.

here is my cut box vs rf dry. inlet area in particular.

[impulse]

I got it because I wanted more whine. 500 bucks for some more whine. Seems ok to me LOL

[Wobble Goat]

Originally Posted by s346k

op: you're trying to split the hairs that have already been split once. i did a lot of testing my cut stock box against a dry rotofab. iats appeared unaffected across the board. basically i concluded that a rotofab was worth 0 over a cut stock box. at speed, on the dyno or otherwise. stock long block: the restriction in the intake system is not the air box, it is the throttle body. but truth be told, my e85/bolt on car saw very little peak power from adding a rf dry and 95 mm tb. but i do think those additions contributed to the preservation of peak power over 6k rpm.

here is my cut box vs rf dry. inlet area in particular.

I appreciate the info. Your testing alone makes me believe there is negligible gains to be made by replacing / modifying the stock intake on any LT1 Camaro that isn't FI.

Doing this for my own satisfaction.

Originally Posted by impulse

I got it because I wanted more whine. 500 bucks for some more whine. Seems ok to me LOL

I bought a stock intake for significantly less than $500; we'll have to see if I have a bit more "whine".

Stock / OEM Air Intake Box



Went to town with some pliers.



Used an oscillator to cut the high points and sand.
Used a dremel to clean up a couple spots the oscillator couldn't reach.
I could go through multiple grits to smooth it out but, no point. Nobody will ever see this on the car and the obstructions have been removed.







I will test with the stock filter, before using the "green filter" for the sound difference.

[BrianL]

Anybody know what is the purpose of those two air veins in the last photo? Maybe the Mass Air sensor needs it?

Is there any potential gains by removing this two also since you are already cutting up the box? Do the aftermarket replacements also have those? Just seems like anything in that area is an obstruction.

[Wobble Goat]

Originally Posted by BrianL

Anybody know what is the purpose of those two air veins in the last photo? Maybe the Mass Air sensor needs it?

Is there any potential gains by removing this two also since you are already cutting up the box? Do the aftermarket replacements also have those? Just seems like anything in that area is an obstruction.

Those 2 "air veins" smooth the air over the Mass Airflow Reader. If you remove them, you will have idle issues. (I know this because years ago I did the infamous "de-screening" on my GTO.) To resolve the issue on my GTO I went maf-less and got a Speed Density Tune.

GOOD aftermarket intakes keep those fins.
https://youtu.be/gYdRNjFof8U?t=406

What I removed from inside the intake box looks more like support and sound deadening. Most of what is inside the air box isn't "finned" to let air through.

[FarmerFran]

Originally Posted by Wobble Goat

Those 2 "air veins" smooth the air over the Mass Airflow Reader. If you remove them, you will have idle issues. (I know this because years ago I did the infamous "de-screening" on my GTO.) To resolve the issue on my GTO I went maf-less and got a Speed Density Tune.

GOOD aftermarket intakes keep those fins.
https://youtu.be/gYdRNjFof8U?t=406

What I removed from inside the intake box looks more like support and sound deadening. Most of what is inside the air box isn't "finned" to let air through.

ahh yes, the infamous screen delete!

[Mountain]

Originally Posted by Wobble Goat

I bought a stock intake for significantly less than $500; we'll have to see if I have a bit more "whine".

I will test with the stock filter, before using the "green filter" for the sound difference.

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.

[Mountain]

Originally Posted by Wobble Goat

Those 2 "air veins" smooth the air over the Mass Airflow Reader. If you remove them, you will have idle issues. (I know this because years ago I did the infamous "de-screening" on my GTO.) To resolve the issue on my GTO I went maf-less and got a Speed Density Tune.

GOOD aftermarket intakes keep those fins.
https://youtu.be/gYdRNjFof8U?t=406

What I removed from inside the intake box looks more like support and sound deadening. Most of what is inside the air box isn't "finned" to let air through.

What I thought was interesting in the airbox hat is the piece of sound deadening material that looks like it was added last minute/as a later finding after the hat tooling may have already been produced. Im stuck wondering if the material was added for NVH purposes or to cheaply cover over some of the vanes to smooth out airflow into the MAF inlet...

[Wobble Goat]

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.

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.

[s346k]

if any of you recall, the ls1 lid had the same raised plastic waffling. the aftermarket lids did not. the absence of said plastic made 0 difference performancewise. i'm guessing it is a sound deadening tool.

[wolfdog]

considering the EPA hoops the manufactures have to jump through...I want to think the cross hatching is some type of noise cancelling scenario but...fluid dynamics does weird stuff that may have been factored in.

regardless...cool project...especially if it nets something.