cheap stock airbox mod
 

Hi guys,

I just completed a stock airbox mod for my FD. The results feel really good. The car pulls a lot stronger. I fabricated a shield, opened up the box, threw in a new K&N and that was it. I bet that this mod gives as good a performance increase as the expensive intakes, at a very low cost. When it is done, you can't see it at all, and neither can the smog guys.

Does it look alot like the one I have posted on my web site?
http://home.earthlink.net/~maxpesce/index.html
and used to be in the Forum Galleries when they were working.

It accomplishes a similar goal as yours but is designed a lot differently. It also uses different materials and mounts differently. I don't have a website. or any photos. If enough people are interested, I suppose I will have to get a website together. I don't know much about computers.

Max,

what kind of HP increase did you get when you put yours in? An estimate will do if you don't have any dyno numbers.

I dont have any dyno #s but did notice a reduction of turbo lag and better throttle responce w/ a 0.5<>1psi increase in BOOST, so I am guessing 10<>15hp gain BUT I also upgraded from the stock airfilter to a K&N at the same time as the airbox mod.

The car goes thru the first 2 gears so fast that it is harder to tell. I really feel a big difference in 3rd gear. It seems to pull a lot harder than before. I have not wound it up very far in 4th..........yet

This isnt about me, but I'll share my mod. I went to home depot and bout 17 inches of a thick heavy vinyle tubing. I think it has a 2.5 inch diameter opening. I dremeled a hole in the bottom of the box about the same size as the hose.

I removed the front passenger plastic piece that is in the nose of the car. I routed this flexible rubber hose between my KOYO and the chassis and eventually into the air box. Then I took some 4 inch tin piping and connected to the hose for a large 4 inch opening and sealed the gaps.

Keep in mind that before I did this mod I got 104.8's for my trap and 13.7's in my 1/4. After I did this mod I got 106.5 to 106.6 in my trap speed and 13.50 in my 1/4. (I run 13.0 @ 108 with my nittos now).

Anyway, it costs under 20 bucks and really works. I can tell it works also becuase my air filter is dirty as hell where it touches the hose, so it must be doing something!

Sounds like a good cheap mod. Mine opens a space in the box a lot larger than yours, and the shield pulls cool air in from the front.

I would like to have a larger opening, but it does bring in cold air and it also leaves the stock intake intact so I do get extra air. I'm no expert, but I would guess that there is a bottleneck somewhere in the Manifold or piping that will dictate a maximum amount of air. In otherwords at some point extra air is not going to help (bottleneck). I dont know if I have reached that yet. I have other plans at some point to do additional things to the intake and I will see if it has any difference.

You are right, there is a maximum amount of air that the system can use. I don't know how much that is either. I just want to let it take all it wants without having to suck too hard.

Just installed Adam's mod! It works great. I'm showing about 1PSI of extra boost and can really feel the extra air ... especially when the secondary kicks in. The car is a bit noisier, but it's a pleasant Vroom Vroom ... kind of goes with the Mazda Zoom Zoom ;)

The best part of this mod is that a CA emissions inspection will never catch it! When the air box is re-installed, it's totally invisible.

I have pictures for anyone who is interested. In a few weeks (if only we had 8 day weeks) I'll have my WWW server back up and will post a link.

Adam did a great job with the shield. It’s very obviously hand made, but also very clean. It fit easily and came with instructions for installation. Adam even fashioned the shield to use an existing (and unused) stock pre-threaded bolthole … he included the bolt.

lets see some pics....im interested...

ready for the shield
 

before the shield and with the radiator foam removed

the shield before installation
 

Notice the excellent reading material in the upper left corner ;)

More later ... gota get the door ...

paranoia ques. Is throwing on any type of intake system gonna be okay with out fuel management? Even putting on a high flow filter and the cold air setup that adam is doing, showing an increase in boost or 1 psi? I wanted to do a hardpipe kit with some filters attached for each turbo, but was wondering if this could be a direct contribution to a lean condition, keeping in mind that my car is completely stock, with a DP happening very soon.

There seems to be a consensus that more than two mods (DP, intake, or catback) will put you in jeopardy of running lean. I personally recommend upgrading your fuel delivery before the second mod, especially if you are going to do the third mod anyway.

James, thanks for the nice write-up, and for posting the photos. I would have posted some if I had a digital camera.

Adam

pic three - almost in
 

Ya know … I’m babying a broken o-ring. It’s only a matter of time until I need a rebuild. My goal is to add on all of my performance mods (DP and this airbox) before the rebuild. If I detonate and puke an Apex seal … no big loss, I was going to rebuild anyway. Now I’m saying this as I also bought a PFC piggyback computer from Wade (great guy!), on this forum. Part of my goal is to do my tuning (adjust the computer) before the new motor. Again, the idea is to do it now, when it doesn’t matter if the motor blows. This doesn’t make the airbox a bad idea, it just explains my willingness to try it.

If my motor was in good working order and I didn’t have the PFC to tune the extra 1PSI of boost down … yes, it would make me nervous.

I’ve read all sorts of opinions about how far the car can be modified without a way to manage the fuel / timing / boost, but considering the cost of a rebuild I would go after some sort of boost controller, computer mod, etc. before I went after a DP or intake. Now doing a DP and intake together … forget it. I’ve met a couple of people on the forum that are getting a 12-8-14+ boost pattern from a DP and intake. This is too much for me to rest easy. At the very least, watch your boost gauge …

Anyway, here is another photo. More later … time for bed and posting with photos takes so long!

almost in 2
 

OK ... the last one went fast ... one more ... then sleep!

in and bolted down
 

Notice the bit of duck tape ... I'm paranoid that it’s going to rub threw my radiator hose.

How difficult is this to install? Do you have really user-friendly directions?

drilling the box and instructions
 

I thought Adam's page long instructions were easy to follow, but you do have to be willing to bend and drill the aluminum shield once. Also, the airbox has to be drilled / cut out. Here is another picture ... two more to come as I have the time.

Adam, if you don't mind I'll scan and post your instructions.

Set me up with the template baby! Who is adam and were do I get this dimensions for this work of art! I was going to fabricate a rectangular duct with essentially two of these template pieces spaced the width between the radiator and the frame, but I think this piece is quite nice.

One thing that could be modded to the mod is to provide a bend towards the bottom that helps "ramp" the air upwards.

bottom of the box
 

Adam is the designer and started the thread ... I got mine from him ... you'll have to PM him or talk him into posting the template. He charges $80 for the finished product. I think that it's worth it. Lots of time to desighn this / fabricate it.

He's more interested in sharing his creation than making money, I suspect that he'll let go of the template ... but ask.

Here is another pic ...

I'll cut my own airbox, that's not the prob, I'll even cut the Al. I'd just like the template.

Adam - any chance of giving/selling the template? Could be some easy/quick $ via paypal and don't have to deal with those nasty rough edges & shipping - eew

Personally, because I hate shipping (the outragous rates of places like Mail Boxes etc and the long lines from the "stay at home" moms shipping crap at UPS) I'd figure shipping as being 50% of the hassel.

The problem is the whole IP (intellectual property) issue. Then he would have to make better one's (ceramic coating anyone) :)

OK, it doesn't look too hard with the right tools I guess. Would I be OK if I go to Sears and pick up a rotary tool? Is that all I need?