My Quick-homemade CAI [Updated]

[marklj]

I've been wanting to build myself a Cold Air Intake for a while now and today I finally got around to doing it.

This was not the way I wanted my CAI to be set up at all, but because of some issues I had to rethink some things. Initially I was planning on getting rid of the stock airbox completely, but because of the MAP sensor and hoses this is the way I rigged it for now.

https://sl-i.net/FORUM/images/imported/2009/02/9krql5-1.jpg

What I did:
1. Removed resonators and stock intake tubing
2. Replaced with some flex tubing with a high flow filter at the end.
3. Took out the stock filter and cut it all until it was just the base frame of the filter (I also duct-taped and sealed the inside of the base frame just incase some of the excess filter wanted to break loose). I then put the filter base back in the airbox. The purpose of the base frame is to make the air box remain air tight.
4. Finally I loosely jammed the front of the high flow filter into the stock air intake entry for any extra cold air from the front of the car.

I drove it around some back roads and noticed a somewhat noticeable improvement in 2nd/3rd gear power. I cant really hear much change in sound though (which was my main reason for doing the project). The fact that the stock airbox remains there seems pretty ghetto, so if any of you have any suggestions on the best way to deal with that let me know.
Anyways, what do you think? Anything I could do to improve on this?

[StatGSR]

yes, um lots of things could be done to improve this.... smooth piping and loosing the airbox would be the best place to start.

[rougeben83]

you could replace the pipe and kept the stock filter, or a KN panel filter...
https://sl-i.net/FORUM/images/imported/2006/10/HPIM0467-1.jpg


The only sensor on the stock airbox is the intake temp (the little round black sensor next to the TB) Just drill a hole and put it in whatever intake tube you decide to do next...

[marklj]

I just drove it around some more today and actually am noticing a lot more more power at around 3-4k. And forget what i said about the sound not being much different, I can hear my engine roar a lot more than before.
I'm still planning on losing the airbox, which should help even more. But the flex pipe is going to have to stay for a while until i can find a place that will custom bend a pipe for me for cheap.


you could replace the pipe and kept the stock filter, or a KN panel filter...

I was thinking about that, but I read heard somewhere that the stock filter doesn't let air flow as efficiently as a high flow cone filter, which is why i chose to do it this way.

[marklj]

So i removed the airbox and made the tubing so it connects directly into the intake. What a difference! It sounds like i have a muscle car when im driving at high (3-6k) RPMs, and also I have better acceleration. The stock airbox really dumbs the car down a lot more than i realized.

Some pics:

https://sl-i.net/FORUM/images/imported/2009/03/210hjx2-1.jpg

https://sl-i.net/FORUM/images/imported/2009/03/2qld8cg-1.jpg

[rougeben83]

The stock airbox isn't really a choking point for the engine. I remember somewhere on NASIOC tech where people were calculating the max flow rates for the n/a ej25's and it's around 350cfm; that's not really a lot of air that the stock engine needs to suck in even at WOT. But anyway, that's not really all that important as its all conjecture.

That dryer tubing though is creating too much turbulence for the intake - it's more than likely slowing the intake velocity when compared to a straight tube.

The next step would be an intake from an RS (00-01 which are also MAP cars) like the AEM from my old setup, or one of those generic ebay ones for $30...

https://sl-i.net/FORUM/images/imported/2007/07/HPIM1684-1.jpg

[subba]

i think the stock would be better, that thing might get warm from engine heat and it will warm the air flowing through it, thats why aluminum is the best, it transfers less heat.

[legacygt420]

get a real cold air- its way better.the stock intake off the bg with that filter will work better than that flex hose u got. i had that same thing ang gave it away quick as hell.looks cool but the stock intake off the previos gen will work way better. then just take that flex crap and put it after the filter down behind the bumper or foglight hole

[99gtlimited]

that flex tubing can cause harmful turbulence and disrupt the intake pulses that the engine thrives on. this can cause uneven airflow to each cylinder.

[LunchBox04V]

Great to see that you killed the snorkus! lol But +1 to the corrigated hose. It has been said that a corrigated hose will flow like a smooth hose half its diameter. Looks great dude, and keep working on it!

[marklj]

Keep in mind this is not a serious attempt :smt002
Since i have a hood scoop I figured i may as well see how putting the filter right underneath would work with getting a endless supply of cold air rushing in. Yes, i know this will reduce a lot of torque, but like i said before, i just am doing this to see the results.

https://sl-i.net/FORUM/images/imported/2009/03/w8b81z-1.jpg

This seems like it could be a good idea if the pipe had more overall distance, am i right?

[jey]

Where the heck is the MAP sensor going to go?

[marklj]

Where the heck is the MAP sensor going to go?

http://mj87.com/subaru/pics/mapsensor.jpg

I drove the car this morning, and it wasn't nearly as bad as I though it would be. Lost some low-end power, but boy does it sound good when it revs high. I'm still going to change it back though this weekend.

[rougeben83]

Where the heck is the MAP sensor going to go?

The MAP sensor is on the manifold on the BE's. What he circled is the Intake Temp sensor...

[OutbackMat]

i think the stock would be better, that thing might get warm from engine heat and it will warm the air flowing through it, thats why plastic is the best, it transfers less heat.

Corrected for accuracy. :wink:

One of these days, I'm going to build my ABS intake with some help from The Depot.