A DigiFantastic Cold Air Intake Project

The car is a '92 VW Cabriolet, 1.8, 8V
DigiFant. AC has been removed.

Start with a spare bottom of the air filter housing.
Remove the factory intake snout. I used a 2 1/8" hole saw
on a variable speed drill and slowly cut out the section
the original snout used to fit into.
 
 

After opening up the hole a bit with a rotary file,
I stuck in a short piece of 2" ABS schedule 40 plastic pipe,
I just eyeballed the length, and secured it to the cut out
air filter box with a hose clamp on each side.
It came out quite solid.

 
There were some gaps to fill, I used black silicone RTV.

 

Let the silicone set up a bit, clamp the airbox down
and check for clearance so far, clutch cable and such.

I used 45° and  90° elbows to get around the left of the
radiator, I think these type elbows are called
"Street Ells".
This view is from the front, looking down.

 
I cut a piece of hose to fit between the air filter box
and the 45° ell.

 

A cross over pipe in front of the radiator.



The intake funnel is a 3" to 2" adapter sleeve,
a 90°, a 45°( I think, might be a 60°) and another 90°.



The top 90° was glued first, the 45° to the top
90°, the bottom 90° to the crossover.
I hacksawed three slots in the sleeve
of the 45° and hose clamped it to the bottom 90°.



The view through the grille.



Visual differences.
 

What was this flat doing in the old snout??



Measured differences.

 

Not taking the flat into account, this slighty
bigger intake has 26% more surface area!!

---

The intake funnel needs a little a little
something additional for support, I'll probably run a long
bolt or some all thread straight down through it from the top.

I'm real happy with the results, seat of the pants dyno
gives this project five stars. It pulls better through the
entire RPM range, seems to pull harder as road speed increases, the ram air effect might just be working!!

As I removed the unmodified box, I left it's fitting in place
below the new intake hose, it can be easily restored for inspection time. It only will be a very sharp smog tech
that spots this mod as is.
Since the warm air flap and diaphragm are still in
place and operational, this thing might even work
during winter in cold climates. The warm air flap
cannot close the modified cold air intake, I didn't care.
Others may choose to spend more time on this area.

If you like the page and want to download it complete,
here it is zipped.
I would be very flattered if this page gets posted
elsewhere on the 'net.
Let me know if you use it, OK??

Ron
austinrc   gotperiodnet