Guides - Modifying Nova GSi front bumper

DISCLAIMER: The information in these documents are a collection from experience (friends or myself), magazine articles, mailing
lists and internet web sites etc. So don't take these as 100% correct gospel, hence I don't take any responsibility for any of these
guides.

Difficulty Rating: 4/5 - A bit fiddly - but worth it

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Created: 16 Dec 2000

Revision 1

Click on any of the pics for

a larger view.

Before...

...and after.

This is a step-by-step guide on modifying a Nova GSi front bumper so
that the middle slat is cut away and replaced with a mesh grille. This
particular guide shows how the air duct is 'boxed in' so that it gives
depth, other mods simply place a big piece of mesh flush with the
surface with the bumper. Because of the boxing in nature, this
modification is difficult to do, very fiddly in places and may take
several weeks to complete (it took me a month to do, as it was the
time I've ever done this sort of thing). But by following this guide, you
should be aware of any problems and be able to do the job much
quicker.

You can buy this modification already done, fiberglass copy front
bumper from

Kingdom Developments

(as seen in many car

magazines). The difference is that the mesh is flush with the rest of
the bumper.

You will need patience, lots of pug (filler), fiberglass and lots of
sanding down and filling back up tasks. I chose to do it this way
because I've never seen it done before and it is unique, even though I
have seen similar, if not identical looking bumpers at recent car shows
(Doh!). This modification also retains the use of the towing eye flap,
that it can be removed without damaging the fiberglass/filler, and your
work :)

PARTS

Nova GSi bumper

Hack saw

Pad saw

Pug (filler)

Fiberglass Kit

Stanley knife

Permanent Marker

Masking Tape

Mesh

Metal cutters

Spray primmer paint

Sanding paper

Glue/Bonding

Sanding block

File

Strong tape

COST

New Vauxhall Nova GSi front bumper

£100

The part number for a new GSi bumper is
90443248. That is the plastic bumper only
(no carriage bar of fixings etc.). Try and
get galvanized steel mesh as this is
protected from corrosion.

Mesh (stretched diamond shape) 1x1.5m B&Q £18

Gray plastic primer spray paint (2 cans)

£5 ea

Just before you start, make sure you note the following:

l

If you've got the Haynes manual for your car, have this is front of you. You'll need it on how to
remove the front bumper if you have to (either that or buy one).

l

Buy various grits of sand paper, 100 is rough, 1000 is smooth, you may use water to make
the job easier. Use 200 grit for first time sanding down, then once it starts to get smooth, use
400 grit. Once all the bad holes and cracks have been filed in, start the very smooth stage of
sanding down with 600-800 grit.

l

To bond on plastic, I used Adhesive, which are two compounds mixed together. Or use Silk-

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o-flex or Tiger Seal that body shops use. Either way, wait 24 hours to dry before continuing.

l

Try and purchase galvanized steel mesh for the air duct, as this has good prevention
properties against corrosion. Use Enamel paint on the metal mesh when spraying.

l

If painting a new GSi bumper (like what is shown in this guide), spray several layers of plastic
primer on. This will show any imperfections missed in the sanding process.

l

When the bumper is placed back on the car, it may be beneficial to paint the front valence
behind the air duct a darker colour (i.e. black). Depending on how dense the mesh is, it may
not seem think enough and you will see the valence behind it.

OK, got all the above? Then follow the steps below (remember to click on the pics for a bigger view):

Step 1

Step 2

Step 3

This is what a brand new front
Nova GSi bumper looks like,
NOTE: it won't be staying like
this for long. The idea is to cut
out the middle slat making a
larger air duct.

Looking from the back, mark
where you want to cut. Use a
permanent marker and masking
tape. In this picture I'm keeping
the side wall and lower ledge,
so I'll cut right on the edge of it.

OK you've got all the tools and
parts, now to make the first cut.
Work from inside the bumper
and chop off all the thin plastic
legs off the top lip and middle
slat.

Step 4

Step 5

Step 6

Use the pad saw to cut the first
side wall. Remember to keep to
the right of this as you can
always file off the plastic you
don't want. As this was a new
bumper the plastic was easy to
cut. Cut all the way down till it
meets the second lip.

Do the same on the towing eye
cover. This piece of plastic is
held into place by the two loops
snapping into the bumper. By
cutting along the side wall, one
of the loops will be chopped off.
Fortunately one loop is still able
to hold the cover in place.

Now with the plastic legs and
side wall cut, there is one final
cut along the length to separate
it from the lower lip spoiler.
You'll need to use the pad saw
to make a start on the cut, after
that use the hack saw.

Step 7

Step 8

Step 9

Use the hacksaw all away along
the dip between the top and
lower lip spoiler. Once the cut is

Now step back and see what
you've done. There's no turning
back now. You're 50% away

Turn the bumper over again to
get at the back. Use a Stanley
knife and cut along the line you
made with the pen. It's very

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complete, remove the strip of
plastic, but don't throw it away!
It will come in handy later on.

from finishing the cutting
sequence. All there is to do now
is to chop part of the lower lip
spoiler off.

difficult to make a cut, not
enough room yet to use the pad
saw. This is to retain the depth
of the recess.

Step 10

Step 11

Step 12

Once you've done enough
cutting with the Stanley knife,
use the pad saw to cut along
length of the lower lip spoiler
and then use the hack saw to
finish.

Using the hack saw, cut along
the edge until you meet the
same spot on the other end.
Again you'll need to use the pad
saw and Stanley knife to finish
off the job. Once is cut, remove
the low lip spoiler.

Take another step back and see
what is left. Both the spoiler lips
are gone now. All the major
cutting of the bumper is over.
Use a file or sand paper to
remove swarf on the surfaces
that have been cut.

Step 13

Step 14

Step 15

All that is left is the side wall and
the bottom half of the lower
spoiler lip. The next job is to do
a lot of filling to get a 'boxed in'
shape. This is to give the air
duct depth and so the mesh
grille won't be right at the front
but further in.

Before doing any filling, remove
all the plastic swarf off the
bumper. The easiest method I
found was to run the Stanley
knife along the edge. With older
bumpers (i.e. second hand
items) the plastic might be a bit
stiffer.

With the middle slat cut out, cut
along the line as shown. You
need this in a few seconds, as
you need this part as flat as
possible.

Step 16

Step 17

Step 18

Place the middle slat along the
top of the cut out air duct. You'll
needed to wedge it in place (I
used some bamboo sticks).
Note: it is not long enough to
cover all of the top, so place it
away from the towing eye cover
(i.e. there will be a gap).

With the middle slat along the
top, put lots of glue between the
mating faces, and again wedge
the middle slat in along the top
(as shown). Leave for 24 hours
to dry.

The middle slat should be firmly
glued in. You may have to trim it
down to size (i.e. it may be too
deep). The gaps in the corner
and what is left of the side wall
need to be filled in (to give it the
'boxed in' shape).

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Step 19

Step 20

Step 21

On the side wall, trim it down
enough so that the 'boxed' in
shape is level all the way round.
Otherwise when the mesh is
fitted, it appears to slope (do the
same to the towing eye flap as
well).

There still will be some plastic
left over, cut a small bit off to
plug up the gap in the side wall
(as shown in the next step).
Bend the plastic near the edge
to that it follows the curvature of
the wall.

Place the small bit of plastic
against the gap in the side wall,
and adjust as necessary. When
complete, put some glue on the
mating surfaces.

Step 22

Step 23

Step 24

You will again need to leave this
for 24hrs for it to set, put
something on them that will hold
the piece together, i.e. a G
clamp etc.

The towing eye flap is where it
starts to get difficult. I want to
keep the towing eye, so that I
can remove it in the future.
Hence I can't fill in the side wall
gap as before. So a frame work
is required so that the side is
split.

From the small bits of plastic
left, cut a thin strip and bend it
at right angles. Glue this onto
the back of the towing eye flap
as shown. Place masking tape
to hold the plastic in place and
also to stop it gluing to the
wrong surface. Again wait 24
hours for it to dry.

Step 25

Step 26

Step 27

Yet again using the left over bits
of plastic, cut a small piece so
that it bridges the gap on the
towing eye flap (as shown).
Again glue this into place and
allow to dry.

With the gap bridged in and the
glue fully dry, you should be
able to remove the towing eye
with no problems.

Use fiberglass on the back to fill
in the hole, or rather give it
some backing.

Step 28

Step 29

Step 30

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Use fiberglass on the other side
wall to make the wall complete.
Again allow to dry before
working on it.

While the fiberglass is out, start
filling in the small gaps around
the rest of the air duct that you
have made with pug.

Carry on with the filler all along
the top part of the wall, as this
can be sanded down at a latter
date to make it smooth.

Step 31

Step 32

Step 33

And again with the filler, pug up
the gaps in the towing eye flap
so that the side wall becomes
solid.

With the towing eye back on the
bumper, use enough filler on the
side wall so that they don't
become stuck together.

Place a thin bit of plastic in
between the gap so that you
can carry on with the filler
without fear of bonding them
together (I used the lid of an ice
cream tub, which is very thin).

Step 34

Step 35

Step 36

With the plastic separator in
place, pug up the wall as much
as possible. Once the pug has
dried, carefully remove the
plastic separator. This should be
possible without the pug
cracking.

Once removed, you can start
sanding down the pug so that
the wall becomes uniform (use
you artistic flair here and make it
curvy as you want) Use 200 grit
to remove most unwanted
bumps and lumps (using water
helps).

Do the same on the other facing
wall, as this is much easier to
do. Again use 200 grit paper to
remove any large lumps and
bumps. Add more pug as
required to get the correct
shape.

Step 37

Step 38

Step 39

With basic filling done, the air

Once all the filling and sanding
is complete, clean the surface

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duct should look like this.
NOTE: this is a long process of
filling, sanding, filling, sanding
again, finding more air holes
and bubbles etc, then do some
more filling....the list goes on.

from dirt and dust with white
sprit. Allow to dry (evaporate
away). Spray the plastic
primmer with thin coats, using a
even spray right across the
surface. Allow 5 min between
each coat to dry.

With some mesh (try and get
galvanized), construct a 'tray'
shape out of mesh. Make the
wings on each side about 3cm
deep, and fold these round the
side walls.

Step 40

Step 41

Once the mesh is cut out and
ready to go on, spray it the
colour you want, in my case I
sprayed it with Black Enamel
paint. Which also helps it stop
rusting as it coats it.

Bond on the mesh and squash
on the mesh wings so it holds it
on. You may have to put some
strong tape in place. Allow at
least 24hrs to dry. Wipe away
any excess with white sprit. Put
the front bumper back on the
car...and job done :).

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