[az4783054]

or it could just be part of the injection molding process.

[BrianL]

[QUOTE=Wobble Goat;10927826]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


I certainly accept that explanation on the existing "air veins" intent. However my (very old) memory of fluid dynamics leads me to also consider the shape of the veins, as both ends appear by photo to be blunt. And blunt increases turbulence. Turbulence decreases efficiency. Granted not by a lot, but since the Dremel is out anyways, why wouldn't some taper of the leading/trailing edges be considered?

My thought here is wouldn't tapering the leading and trailing edges preserve the design intent, but also decrease potential for added turbulence caused by the blunt edge faces in the airstream one is trying to optimize? I get it for production cost and ease of manufacturing purposes, but thinking that a shape like an airplane wing or propeller may be more efficient vs. a blunt leading and trailing edge in a device meant to increase airflow. Just a random thought from a retired engineer...

[Wobble Goat]

[QUOTE=BrianL;10928560]

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


I certainly accept that explanation on the existing "air veins" intent. However my (very old) memory of fluid dynamics leads me to also consider the shape of the veins, as both ends appear by photo to be blunt. And blunt increases turbulence. Turbulence decreases efficiency. Granted not by a lot, but since the Dremel is out anyways, why wouldn't some taper of the leading/trailing edges be considered?

My thought here is wouldn't tapering the leading and trailing edges preserve the design intent, but also decrease potential for added turbulence caused by the blunt edge faces in the airstream one is trying to optimize? I get it for production cost and ease of manufacturing purposes, but thinking that a shape like an airplane wing or propeller may be more efficient vs. a blunt leading and trailing edge in a device meant to increase airflow. Just a random thought from a retired engineer...

I agree with you, but I fear any changes to the MAF housing will result in required retuning of the car which I'm not ready to do just yet.

[s346k]

[QUOTE=Wobble Goat;10928564]

Originally Posted by BrianL

I agree with you, but I fear any changes to the MAF housing will result in required retuning of the car which I'm not ready to do just yet.

much of a change in airflow at all will result in poor performance without rescaling the maf. my car lost 7 mph at the drag strip with a cut airbox. i made 4 passes that night. went back the next week with the stock box back on and it was where it should be. the performance hit was also mirrored in some pulls i made on the highway with another car.

[weemus]

Has anyone measured the stock airbox inlet opening versus the RotoFab? Curious if there are any differences in square area.

[wnta1ss]

On the cut airbox thing, there was a track test of a cut airbox with a green filter vs a rotofab cai on an SS posted a while back. Thread here https://www.camaro6.com/forums/showthread.php?t=517532

[weemus]

Yeah, I read that. Too many variables in a drag strip run. Looking more for physical measurements or flow bench data. Doesn’t seem to be any amateur flow benchers on this forum.

“In God we trust, all others must bring data”

[wnta1ss]

Originally Posted by weemus

Yeah, I read that. Too many variables in a drag strip run. Looking more for physical measurements or flow bench data. Doesn’t seem to be any amateur flow benchers on this forum.

Flow bench numbers would only suggest that something could potentially make more power. That test showed us something far more important than flow bench numbers, namely, that the actual performance of the car was better with the rotofab than with the cut box/green filter combo. As far as the variables, the poster of that thread noted the atmospheric conditions, and the cut box/green filter actually got a small advantage of a better DA than for the rotofab. Meaning, a small advantage was effectively given to the cut box/green filter combo, but the rotofab still beat it.

[s346k]

Originally Posted by wnta1ss

Flow bench numbers would only suggest that something could potentially make more power. That test showed us something far more important than flow bench numbers, namely, that the actual performance of the car was better with the rotofab than with the cut box/green filter combo. As far as the variables, the poster of that thread noted the atmospheric conditions, and the cut box/green filter actually got a small advantage of a better DA than for the rotofab. Meaning, a small advantage was effectively given to the cut box/green filter combo, but the rotofab still beat it.

iirc, no info was given on how the box was cut or any confirmation in the form of another pass. i wouldn't call one trip down the track conclusive evidence.

[Mountain]

Originally Posted by 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.

Understand and good point. But unless youre comparing nearly the exact same geometry to the exact same geometry, the difference largely being the vanes, it’s an assumption about the vanes. If the angles into the intake tube from the airbox, the ID sizes or the shape of the box (mainly hat) are different... air filter shape...

My point is, in consideration to the OE tune/not changing the tune, I started to mess with the vanes and I didn’t like where things were going and felt it unwise to go further without a better way to measure minor changes to understand what I was doing. Like I said, hell, maybe knocking the whole thing clean does the trick, where 80%, 90% drops power due to weird flow...

If you look at the Vararam videos, you can see a snapshot of the CFD they ran on their box, which is very similar to the OE box. Their box seemed to be completely smooth, but it’s hard to know how similar, internally, it is to the OE box. I’d mainly be curious in regards to the bottom box.

[RobbyBeefcake87]

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.

I think some aftermarket CAI's might have them but my GM CAI did not. Kind of wish it did, I had a Velossatech BM scoop which I took off because at speeds of over 130mph or so near the top of 4th gear the car was having issues where it would go into reduced power mode out of nowhere. From what I read and others experiences it seemed the MAF signal might have been jumbled up, maybe those fins would have helped in my case lol.

[s346k]

i studied the vararam videos. what i took from them was they could not, in honesty, offer an air box better than a cut stock one. at least not one to merit a $500 price tag.

there's a fair chance i'll have my car on a dyno again this spring. ill take my cut air box with me and swap them while it's on the rollers. i did exactly that with a stock tb and a ported tb last year. the car gained nothing from a ported tb. bolt ons only.

[6spdhyperblue]

Originally Posted by RobbyBeefcake87

I think some aftermarket CAI's might have them but my GM CAI did not. Kind of wish it did, I had a Velossatech BM scoop which I took off because at speeds of over 130mph or so near the top of 4th gear the car was having issues where it would go into reduced power mode out of nowhere. From what I read and others experiences it seemed the MAF signal might have been jumbled up, maybe those fins would have helped in my case lol.

Rotofab does look to have a cleaner maf signal than the gmpp

[lt4camaro]

Modded my stock air box to pull air from below the stock air intake while keeping the the stock opening functional also. Pulls no underhood heated air this way and have extra air volumn inside the air box with all the grates removed. This provides access to air cavity in front of the wheel house down low and there is a constant source of fresh air while driving from factory air inlet and my opening.