Stock airbox modification idea - will this create issues? Carbon fiber fun!!

[JeffK2019]

So I may get an aftermarket CAI eventually but wanted to try modifying the stock airbox first. I am not convinced that most aftermarket CAI are actually directing much more cold air into the intake area than the stock box once the filter is changed.

Currently:
Can remove stock air filter and replace with AEM or K&N filter ($30-50). This should remove filter restrictions.
Remove the secondary carbon fiber filter (very easy, takes 2 minutes).
Stock airbox only has one small intake area pulling air from behind grill (so not hot engine bay air) but seems fairly limited.
Stock intake area does not appear to get direct air flow at speed (it has air access behind grill area but air isn't forced in at speed from what I can tell).

Improvement - would like to force air into box, particularly at highway speeds - but not restrict current grill area/engine cooling.

Using carbon fiber (I have a bunch just sitting here from making longboards) I am thinking of creating two air inlets that pull air from the tow hook area (x2) which would feed into one new inlet entering the box from the bottom. See pictures for visual. I think Option 1 creating a rectangle inlet would allow the greatest influx of air and be uniform across the entire air filter.

My main question - how much suction/pull does the engine create and would my forcing air into the airbox at speed cause that air to then blow OUT the front inlet area as the path of least resistance and then starving the engine of air? Or will the engine be able to suck up that extra air and utilize both intake areas? I would only see this as a potential issue at 60 MPH+ speeds. I could create baffles within the carbon fiber draw pipe to slow down flow but don't want to restrict airflow any unless needed.

So in summary - 2-3 inch shroud in carbon fiber (sealed) around tow hooks (x2) will pull air into single tube (4 inches probably) that will then enter stock airbox from the bottom creating a new intake area.

Bad idea? Going to create issues? I personally think this will truly bring cold air into the intake area while maintaining the stock look and using the existing airbox.

 

[stevj]

My main question - how much suction/pull does the engine create and would my forcing air into the airbox at speed cause that air to then blow OUT the front inlet area as the path of least resistance and then starving the engine of air? Or will the engine be able to suck up that extra air and utilize both intake areas? I would only see this as a potential issue at 60 MPH+ speeds. I could create baffles within the carbon fiber draw pipe to slow down flow but don't want to restrict airflow any unless needed.

Well, using rounded numbers, the 5.7 liter engine pulls in 5.7 liters of air for every two revolutions, and 5.7 liters is just shy of 350 cubic inches.
If I figured the math correctly, at 3000 RPM the 5.7L engine is trying to pull in 8550 liters of air every minute (1500*5.7=8550). That's just over 300 cubic feet per minute.
What's left, now that engine air needs can be computed, is to figure if the maximum air flow rate into the air filter box from the existing intake behind the grill easily supports the air flow needs at your maximum expected engine RPM. If not, it's time to make modifications to the air filter box.
No need to be concerned about air being forced back out the front inlet. The air filter box would have to be under some pressure from another inlet source for that to happen, and if the air filter box is under pressure from forward motion, the engine is getting all the air it needs.

Steve

 

[whetrick1]

Really don't know the math but by writing down the mileage and gallons of gas. I put in a Cai and had just a bit over a 1/2 tank of gas.was getting 18.98 mpg and when I filled up today it averaged out at 19.44 mpg. That's in a 1/2 of a tank.. Numbers don't lie. So the CAI does work I. My opinion..

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[Patsy1099]

I’m thinking the restriction isn’t more fresh air (yet) but the size of the box and filter (size/type). So putting on a CAI with a larger box and better (bigger) filter can make use of more air. That leaves the question of whether that increased airflow can be properly utilized without telling (reprogramming) the ECU

 

[whetrick1]

Well the CAI I got bolts to the bottom of the original air box.


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[stevj]

Really don't know the math but by writing down the mileage and gallons of gas. I put in a Cai and had just a bit over a 1/2 tank of gas.was getting 18.98 mpg and when I filled up today it averaged out at 19.44 mpg. That's in a 1/2 of a tank.. Numbers don't lie. So the CAI does work I. My opinion..

Looks like the air inlet is the same as stock. If that's the case, then you're using the same "cold air" source as stock and the improved numbers are probably a result of greater flow rate of that aFe filter over the tiny OEM thing.

Steve

 

[securityguy]

Really don't know the math but by writing down the mileage and gallons of gas. I put in a Cai and had just a bit over a 1/2 tank of gas.was getting 18.98 mpg and when I filled up today it averaged out at 19.44 mpg. That's in a 1/2 of a tank.. Numbers don't lie. So the CAI does work I. My opinion..

Sorry but I'm not sold on your comment above as there are FAR too many variables involved to say that you are getting roughly 0.5 mpg better than before. Driving conditions...roads traveled...temperature...humidity are all variables that cannot be controlled. In addition, you only ran 1/2 tank of gas which is nothing in the scheme of things. Don't get me wrong...I love CAI's and the sound they make but I don't feel you will see anything in terms of increased performance or mpg and, if so, it will be negligible.

 

[whetrick1]

Well my driving is an average of city and highway. When you figure the gallons you put in to the mileage the numbers don't lie. You don't have to be sold on it.


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[Blvckr3bel]

With my S&B intake it uses the factory snorkel location and also has a large cutout on the side above the passenger wheel for additional optional airflow. Comes with a rubber seal if you chose not to use the extra port. With that being said, maybe a 1/2mpg difference but there are too many variables to say that it is true. I only bought it because it makes me smile when i pop the hood. In all honesty expect nothing from a CAI without other supporting mods.

 

[Nails]

OP, great thinking. As I have been studying this option also. Just haven’t had time to break it down and get in to engine bay.

We can debate left and right. I’m all game for what ever options you all choose. I will say just with delete and drop in on stock intake, I’ve gained mileage .5-1ish depends with variables. There was a obvious gain.

Unless we do something about the exhaust manifolds at minimum or on down to make engine itself more efficient. Huge gains(claimed) won’t be seen.