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  Air Intake System  
Added 2006 January 04  
  One of the areas I have been exploring on my latest conversion is the Air Intake System on a 2WD Vanagon.

I wanted to achieve an arrangement that used the Subaru stock air tube and either a K&N type filter or use a modified Vanagon air filter box.

Here is what I came up with:

Things to note are:

- Wedge between throttle body and intake header - rotates throttle body down by 20 degrees.

- Cutout in fire wall to clear Subaru intake tube - notice how nicely the tube fits under the deck flange.

- MAFM is mounted with a standard Subaru flange available from most FLAPS (Friendly Local Auto Parts Supply)

- Plumbing street elbow to connect to K&N type (not oil impregnated) filter.


  Here is a picture of the throttle wedge I had machined up:

The original idea for this wedge came from Al Wick (fellow list member) - the biggest trick with the wedge is getting the bolts threaded into the header and then a nut on the throttle body side. After a bit of hair pulling and head scratching I got it working just fine. Added gaskets on both sides of the wedge. This solved the interference problem between the stock Subaru air tube and the vanagon deck flange on a 2WD van.


  The next thing was to come up with a support bracket for the MAFM:

I just used a commercial flange that is available for mating K&N filters to Subaru MAFMs and a 3" plumbing street elbow to attach the K&N type filter. The adapter flange is rigidly mounted to the side of the engine bay - using a short piece of angle iron.


  I then fabricated two air filter arrangements:

The Ractive adapter is just a 3" plastic plumbing street elbow with a PVC joining tube.

The Vanagon air filter box is quite a bit more work to reshape it and again I use part of a 3" plastic plumbing street elbow to connect to my MAFM flange.

This is what the Vanagon air filter box top looked like before I painted it;

Top outside                                                                                                Top inside

The elbow is sealed into the box using epoxy resin and some filler to fill in the gaps when I got finished reworking the old vanagon filter top. Looks much better when it is all painted up.

Here are pictures of the two installations:

The first picture above shows the Ractive filter arrangement.

Here it is close-up - viewed through tail light hole.

Another shot of the engine bay with the Vanagon air filter box.

  Assessment of these arrangements:

1) The wedge works very nicely and allows use of stock Subaru air intake tube.

2) K&N type (Ractive) filter worked very well but was a bit noisy.

3) Vanagon air filter box seems to work the best - at the moment I do not have any snorkel on the box - it is just sucking air in from the driver side air vent.


Please let me know what you think of this arrangement - comments good or bad are welcome.

NOTE: Use these ideas at you own risk - no warranty or guarantee implied or included.  Tom

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