Other things… 👀

As a car guy I’m always looking for new ways to upgrade the bits and pieces of my vehicles to fit my personal preferences.

That includes each and every little thing down to the trim colors haha.

well, returning to an old vision I had when I started BSI, I decided to yank my airbox out and see if there were ways to improve it.

At first glance, the factory airbox is actually very well designed. For the most part I probably wouldn't change much about it but rather modify some key elements to be more efficient.

For starters…

THE SNORKEL…

First off, the inner diameter is 3.5” which matches the rest of the BSI system’s diameter. However, the maf tube section of the airbox (As we discussed when we talked about the 83mm maf tube) is merely 76mm or 3” diameter.

The snorkel also consists of three pieces. The inlet, a mesh coupler, and finally an elbow piece that attaches to the airbox and houses another intake silencer to quiet down the intake noises.

Secondly, the coupler joining the snorkel to the airbox flange and silencer is made of a mesh canvas type material that is porus enough to breath through. This in itself is a restriction as the snorkel is the airbox’s main source of fresh air. The porus material allows air to be pulled through it short of the mouth of the inlet that sits in the path of the grille. Think of it like trying to suck air through a straw with a crack in the side, except in this instance the crack is a bunch of pinholes.

While all of this is pre-maf and pulling some air through the mesh coupler isn’t going to hurt anything or cause a cel because it is unmetered. The coupler sits right next to the engine block and cooling system and is allowing hot air from the engine bay to be pulled into the airbox.

Lastly… The elbow piece.

The elbow tapers down from the 3.5” coupler to roughly 3” entering the airbox (approximately. I didn’t get a chance to measure it). Attached to the elbow is an intake silencer much like the ones you find on the factory supercharger to airbox elbow. It’s purpose is to quiet down and restrict the airflow. It’s gotta go lol…

To add to all of this the elbow and inlet are two piece halves that clip together and leak like a sieve under pressure. So basically… While the oem snorkel provides a decent straight shot to the airbox for air to flow through, it’s not super efficient and hot air does get drawn into the tract.

Because the coupler and elbow pieces aren’t single airtight pieces, pressure or draw to the mouth of the inlet is weaker as hot air is also being pulled from the neck and base of the snorkel. While the inlet is also a two piece design, it’s so close to the source that any leak from seams is negligible so we won’t worry about that.

Being pre-maf and pre-airbox, you wouldn't think this would matter and, in terms of horsepower you would be correct… mostly…

With a more sealed snorkel, removing the leaks creates more pressure to draw from the mouth of the inlet where fresh air is sourced. It also would remove the draw of hot air from the engine bay which could in turn lower pre-intercooler temps which… would equate to lower post intercooler temps as well as allowing for more volume to take advantage of smaller pullies and bigger intakes, nitrous, etc…

Lower intake temps CAN result in gains… While minimal and, as just an added benefit of possibly 1-2hp on a good day, the gain would be more like a reclamation of existing power from inefficiency than an actual added gain. In short, it’s nothing groundbreaking but, it is a good supporting mod to add to the mix if you plan on modding beyond the typical basic bolt ons but want to keep the factory airbox.

In search of a way to recoup some lost mini horses I decided to try to fit a couple of different options using spare materials that I had laying around.

First, I tried just replacing the coupler between the elbow and inlet.

While this works to remove that porus canvas coupler and a large source of heat from the intake tract, it still leaves the silencer and leaky two piece elbow in place. Still a great option, but I personally need a total solution.

Enter this weird looking chimera...

Turns out the inlet to the airbox is an ovalish 3.5” diameter lol.

This makes sense to me… just a basic mock up but, it works and it creates a sealed system that provides an uninterrupted stream of fresh cool air to the airbox.

Considering this is just a quick prototype mockup, it will need some adjustments and alterations in order to be 100% perfect, but… it’s definitely doable to turn the oem airbox into a fairly efficient ram air system. 👀

The real question though, is…

Does it fit???

Why, yes… yes it does. 😈

It fits well… almost well enough to start working on a production model… 😈💯

Give us some feedback! Should we pursue a high flow airbox conversion kit?