Box and Pipe Fabrication - MK7 GTI Induction, Part 2

Box and Pipe Fabrication - MK7 GTI Induction, Part 2

The prototype for our MK7 GTI intake system will be unique. While designing the airbox, we needed to accommodate the factory mounting points, the battery cable routing, proper filter placement inside the box, and the stock fresh-air inlet scoop. Let's take a look at the gradual progression to a fully functioning prototype!

We gathered some piping in our garage and tack-welded together an intake tube route. We then sorted through our air filters to locate an appropriate air filter that would fit within the constraints of the airbox we had in mind. The filter will be placed right next to the fresh-air inlet, optimizing the amount of fresh air that will pass through the pipe.

The Piping

MK7 GTI intake prototype

MK7 GTI intake prototype

It's pretty liberating when we don't need to work around designing for a MAF, it gives us more freedom with choosing a tubing size. We plan on using 3" piping from the filter to the turbo to maximize the amount of airflow. The turbo inlet has a diameter of 2.5", so we used a 2.5"-3" coupler to adapt our piping.

MK7 GTI intake turbo inlet

The Airbox

We decided to design the airbox after having a solid idea as to how to route the tubing. This step makes it easier in terms of planning and fabrication. The task of laying down base schematics for the airbox was a bit more daunting than usual, but we wanted to incorporate some of the OEM features, such as stock mounting points and the air scoop. We also needed to design around the battery cable that is routed underneath the stock intake airbox.

Using drafting cardboard to set up fabrication

Our engineers created the initial design by using moldable drafting cardboard, then it was on to metal fabrication. Remember, we are using all aluminum for this application.

MK7 GTI parts tack-welded into place

Fitting the filter onto part of the airbox

Fitting the filter onto part of the airbox

Fabrication and Fitment

Once the shape started coming together, we began piecing together more of this box.

Fitting the pipe onto part of the airbox

Off to tack-welding and test fitment!

Welding together the MK7 GTI parts of the box

Shot of a partially assembled MK7 GTI intake airbox

Now it's time to start constructing more of the airbox. Exact dimensions were critical here, we needed to ensure this piece installs in an easy manner.

Taking measurements of prototype MK7 GTI parts

Taking measurements of prototype MK7 GTI parts

Once we had some bent-and-cut aluminum ready to be welded into place, I noticed one of our fabricators cleaning the metal pieces with acetone. He explained that after cutting and bending sheet metal, you must use acetone to clean the surface adequately before beginning the welding.

Cleaning the prototype MK7 GTI parts with acetone

Contaminants such as glue on the surface can cause weld defects that result in an overall poor appearance. This process is the cleanest and most professional for weld preparation. Even for just a prototype, Mishimoto likes to go above and beyond when it comes to quality R&D!

Here are some shots of the full airbox being assembled.

How the lid will fit on the prototype

Welding the MK7 GTI intake prototype

Welding the MK7 GTI intake prototype

A couple shots of the finalized prototype fully assembled!

Fully assembled airbox

Fully assembled airbox

As the box was secured into the bay with no fitment issues, we reached the end of the fabrication process for this prototype!

Fitting the airbox into the engine bay

Fitting the airbox into the engine bay

Aerial shot of the completed prototype system

What's Next?

We need to dyno test our system to see if it improves the stock performance and also how it will perform with a tune. Our MK7 did come with aftermarket performance software, so we will have those numbers for you soon. Stay tuned!