|240 TURBO SCOOP MODIFICATION TO AIRBOX
by Paul Schuh
This is a bit more radical alternative to modifying the 240 Turbo airbox. It
costs a little more and takes more time than the PVC pipe mod, but it really
opens out the front of the box.. This mod continues to utilize the factory air
filter in its current location but essentially places your filter well into
the air pressure front at the nose of your car.
This modification requires you to work with fiberglass. Do not be afraid! It
is not difficult, in fact the first time I ever saw fiberglass materials was
when I decided to begin this project. Take your time and you should not be disappointed.
CAUTION: both the fiberglass materials and gasoline
required to complete this project can be hazardous if mis-handled. Complete
this project in a well ventilated area, not your basement. Dispose of hazardous
Most of the material required for this mod are available at a well stocked
hobby supply store:
- Approx. 1 ft by 1 ft block of styrofoam. (You may want to get extra so
you can experiment with shapes.) This will be used to model the shape of the
- Fiberglass cloth This will form the body of the scoop
- Fiberglass resin (usually comes in quart metal container. A quart should
be enough) This will interact with the cloth to harden the body
- Flat black spray paint To color match the scoop to the airbox
- Half a gallon of a gasoline Used to dissolve styrofoam from finished scoop
- Sandpaper (various grits) To rough up and smooth out various parts of the
- Sharp knife and coping saw To cut airbox and radiator support
- Cheap paint brushes To spread fiberglass resin
Preparation: If you can find one, get an airbox from
a junk yard so you can take your time with this and not install it until youve
got it just the way you want it. Otherwise, start by removing the airbox from
the car as described in the PVC Pipe procedure. Remove the diverter
flap and all of the side piping. Thoroughly clean the box of any grease, oil
- Cut out the front, and side of the box to include the side tube that leads
down to the diverter valve. There is no need to cut beyond the mid-point of
the sides (proceeding from front to back). Extend your cut into the bottom
of the box up to a point about three quarters of an inch to where the air
filter seals to the bottom. CAUTION: DO NOT get too close to the filter because
if it does not seal well, you will suck in unfiltered air. Also, DO NOT get
closer than three quarters of an inch to the rim at the top of the box. You
need to leave some material to attach the scoop to and you need the rim to
maintain its rigidity to still seal well with the airbox top. By this point
you will have removed about 30% of the material that comprises the box. Set
the box aside.
- In order to proceed, you will first need to provide a larger opening in
the radiator support for the air to pass through. I started with the small
circular opening that the existing tube passes through and extended that hole
towards the right side of the car to incorporate another existing hole:
Feel free to experiment with other shapes and sizes. Just make sure to eyeball
the back side of the radiator support to make sure your scoop will be able to
cover the whole opening. The opening could actually be quite larger than I made
it. I just didnt want to take too much material out of the radiator support.
When youre happy with your opening, smooth out the edges with sand paper.
- If you cut-out a junk yard airbox in step 2, at this point you will have
to remove your existing airbox. Place the cut-out airbox on its mounting point
and picture in your mind the approximate size and shape of the scoop that
will be needed to fill in the opening in the box to the opening in the radiator
support. In my case, the hole in the support was well below the airbox so
my scoop had to sweep down. The hole in the support was also smaller than
the opening in the box so the scoop had to change in area of cross-section.
- Place the styrofoam block in the cut-out of the airbox and secure it with
masking tape around the sides and bottom.. Begin shaping the foam by removing
material with a knife, saw, or sandpaper. Check your progress frequently by
placing the work-in-progress in the car to see how things are
shaping up. This will be the most tedious part of the process.
- When the scoop is shaped the way you want it, use a marker to draw a line
on the foam just outside the box at the point where the foam enters the box,
then remove the tape and foam from the airbox. Now you will build-up
the fiberglass scoop over the foam up to the point of the line you just drew.
Follow the directions on the resin can for laying the glass. It will
be a several step procedure with resin impregnated cloth wrapped around the
foam, allowed to dry and additional layers added for strength. Its best
to work with the cloth in strips about 3 inches wide. The exact dimensions
on the edges is not critical because the glass can be shaped and smoothed
inside and out when dry. Just make sure you get it thick enough to have some
extra material to sand if youre worried about smoothness.
- When the scoop is fully dry, test fit to airbox to make sure you got it
right, including checking it in the car again. When you are satisfied, pour
gasoline on the foam . This will melt foam but not harm the fiberglass. Thoroughly
clean out scoop of foam and gas. Attach scoop to airbox using additional strips
of fiberglass around sides, bottom and a little at the top under the lip (you
did leave room, didnt you?) Rough up the airbox where fiberglass will
mate using rough grit sandpaper. This will help your resin wet cloth glue
to the plastic.
- Let your new airbox completely dry. Test fit in car again and sand front
edge of scoop if necessary to get a close fit to back of radiator support.
Sand any other rough spots inside and outside of scoop. Clean out scoop again.
Your new scoop will be a opaque white color. Spray flat or semi-gloss black
to match airbox.
- Re-install new airbox, filter and fuel distributor into car.