DIY Velocity Stack Mod

[koji]

Credit for the idea for this mod goes to SaggioWRX who did an awesome job on my tint.

For those of you who have removed your resonator, I'm sure you've seen the gap that exists between your stock air box and the hole in the fender. This mod allows you to close that gap and seal off the airbox so that it will only take in air from the fender.

What you will need:

1. 3" Plumbing ben connector with one male and one female side.
2. File or Dremmel
3. 12mm socket wrench with 12" extension
4. Screw Driver - Flat and Phillips

[koji]

1. Carefully unhook the throttle cable from the air intake snorkel.
2. Remove the cooling lines from the intake box.
3. Unscrew the brackets holding the snorkel pice to the airbox and the intake.
4. Remove the snorkel piece.
5. Unscrew the 2 12mm bolts that are holding the airbox to the car.
6. Remove the airbox from the car
7. There is a circular rubber piece attached to the airbox by 3 plastic screws. Remove this piece.

Here's a look at the rubber and plastic piece you just removed in step 7.

[koji]

I verified that the bend will fit into the airbox by putting the male end of the bend through the Rubber piece from step 7.

Here's a pic of the bend with the rubber piece over the male end.

[koji]

Here's a look at the hole in the airbox that you'll be inserting the bend in.

You'll notice on the right side of the airbox that it's not perfectly circular, there is a flat area which is why it's necissary to file.

[koji]

I wanted the bend to sit in the airbox and be pointed at the front bumper at a 45 degree angle. You could do it differently if you like.

1. After fitting the bend into the circular rubber piece, arrange the bend at the angle you'll want and mark the area that you'll need to file.
2. You shouldn't need to file more than an 1/8th of an inch off the bend.
3. Check for fitment periodically as your filing.

Here's a look at how the whole thing will fit together inside the car.

[koji]

For those of you who removed the intake resonator, this procedure is familiar:

1. Unscrew the 3 plastic screws that attach the inside (plastic) of the fender to the fender.
2. Unhook the metal clip on the front edge of the fender that attaches the plastic to the fender
3. Roll the fender plastic to the outside of the fender edge.

Here's a look at what you'll need to do once the clips are removed:

[koji]

1. With the plastic bracket of the airbox removed put the bend inside the fender and put the male end throught the fender hole.

2. Place the plastic bracket over the pipe bend.

3. Put the bottom section of the airbox into the car but do not bolt it back in.

4. Line up the pipe bend and the airbox and push the plastic bracket flush to the airbox. The rubber that surrounds the plastic bracket will not go inside the airbox anymore but you should try and push it flush to the side of the airbox as much as possible.

This will create a good seal around the bend and with the airbox.

I verified this seal while I was filing down the bend and trust me that it's a very good seal

Reinstall the rest of the airbox in the reverse order you removed it.

[koji]

Here's a look at the rubber bracket pushed up to the side of the airbox.

[koji]

Here's how much of the bend is inside the airbox.

[is2scooby]

Anothere nice mod and accompanying tutorial, Koji!

[koji]

Thanks Richard!

One benefit that I noticed from this mod is that the intake is now much more quiet than it was previously. It now sounds like it did prior to removing the intake resonator. It was cool to hear the intake for a minute, but after a while and on long drives, it got fairly annoying.

[blackshadow]

Thats cool! But if it sounds the same as stock then why not just put the resonator back in? I mean i could not find any performance gain....

[Big Sky WRX]

It would be nice if one could keep going w/ that elbow, hooking back into the snorkle. I truly think there would be gains (maybe small) w/ a piece that hooked up the snorkle to the airbox- w/o the resonator. Prova makes such a setup for $250! . I'm sure it could be designed/made for much less.

Thank you. You've given me good food for thought.

Big Sky

[koji]

It would be nice if one could keep going w/ that elbow, hooking back into the snorkle. I truly think there would be gains (maybe small) w/ a piece that hooked up the snorkle to the airbox- w/o the resonator. Prova makes such a setup for $250! . I'm sure it could be designed/made for much less.

I was thinking the same thing . the good news is that it'll be easy to figure out since I have the resonator out and can measure the gaps easily without getting into my fender...

[Big Sky WRX]

I'm going to tear into this weekend and have a look see. I'm thinking you could retain the portion of the silencer that bolts in to the wheel well and connects to the snorkle. As the snorkle as it goes it the silencer is weird shaped (flattened oval) and would probably be tough to fit w/ conventional pieces.

I'm not familiar w/ plumbing bits at all, does the 3" stuff come in a variety of lenghts, bends etc? It looks like the perfect stuff- right diameter, smooth on inside, even black to match.

Thanks

Big Sky