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How To Create A Custom Cutoff Shield (Nov 23, 2007)

'Shield Mod' refers to replacing an existing OEM projector cutoff shield with a custom cutoff shield. OEM shields are designed in such a way to meet certain DOT/ECE standards and regulation. In some cases, regulation can control and limit your output. With shield mod, if done correctly, you can optimize your output in terms of intensity, width, cutoff pattern, color, and sharpness. Shield mod can be used to convert a RHD to LHD cutoff.

WARNING: Shield mod is not something to be taken lightly. A small imperfection can magnify into a larger imperfection, as we are dealing with projection. The following general procedures show how I did it with good results; however, I do not promote modding your OEM shield. This is an individual effort. If you plan to follow the procedures described below, please use cautions and take into account the risks involved. Results may varied.

Here's a sample of an S2K beam with OEM shield at 20ft with Philips 4300k D2S bulb.
Sharp and straight, but sloping downward on the left and softened on the right sides.
S2K beam with modded shield for a more evenly spread output while still maintaining sharpness, color,
and brightness.
OEM cutoff at a different angle. 20ft from wall. Modded cutoff. Completely straight across, more concentrated light below the cutoff on the left side.

Material Needed
Below is a picture showing all the materials needed in this project. You will need a flash aluminum sheet, which can be found at OSH. It comes in differnt thickness. You want the thinnest, which is about 0.2mm. You will need an exacto/utility knife, scissor, a straight-edge ruler, double-side tape, #6 nut/bolt with #8 washer, an OEM cutoff shield for reference (I will use an S2K for this project), and something round like a medication bottle or battery for rounding the flash shield.

Materials used in this mod. Obtainable from your local home improvement stores.

Create an S2K Shield Template
Since different projectors have different cutoff shields, I will use an S2000 cutoff shield as an example, but these procedures can be applied to other projectors as well. First you need to measure the width and height of the OEM shield. Since the S2K cutoff shield is curved, you can use a piece of paper and wrap it along the curvature of the shield, and mark the edges. Then use the paper as template, and cut out a small piece of aluminum flashing to work with.

A piece of paper can be wrapped around the curvature of the s2k shield. Mark the height and width with a pen. Use the paper as a template to cut out a flash sheet with a height of 30mm and a width of 85mm.
The shield height is only 15mm, but I addd another 15mm for creating a mounting tab.

Create Custom Shield From Template
Next, we will cut the flash sheet to give us the 'two-step' OEM output pattern. The upper and lower step on the shield should be between 0.5mm to 1.0mm in height. Use an exacto/utility knife to cut. The cut has to be straight and precise, or else you will get an unever cutoff beam. The key is to use double-sided tape. This will keep the ruler and the flash sheet together, and prevent any movement while you cut. Continuously slide the utility knife along the steel ruler until flash sheet is cut. Be consistent and slide in one direction only. See pictures for detail.

Use double-sided scotch tape to hold the rule and the flash sheet together.
The lower and upper step should be only .5mm to 1mm apart.
Continuously slide the exacto knife in one direction along the ruler.
After about 30 slides, a clean cut is made. Cut the hair-like piece of the shield at 45 degree angle to get an OEM slant cutoff step

Next, cut the remaining shield using the scrapping method with utility knife and ruler. As before, use double-sided tape to prevent movement while cutting.

Cut the remaining tabs. You can use one of the tabs and create an H-shape mounting tab with 30x15mm dimension.
Save this part for later. It will be used to create a mounting anchor.

Round The Custom Shield
The s2000 cutoff shield is curved. The reason why it is curved is to accommodate the curvature of the lens, yielding a wider cutoff beam. The following steps show how to create a curve shield. A medication bottle or a 5v battery is perfect for this. Wrap the flash shield around the battery to round it. It is very important to wrap the shield horizontally around the battery. If not, you'll get a crooked shield, and you'll get a frowning or smiley cutoff beam. A horizontally straight shield will give you a horzionatally straight beam output.

Use a medication bottle or battery for rounding the shield.
Do NOT wrap the shield at an angle. This will result in a crooked beam output.
The correct method is to wrap the shield horizontally along the battery.
This will give a straigth beam output.
Wrap the flash shield around the battery, keeping it straight OEM s2k shield vs rounded custom shield (back view)
Front view

Create Mounting Tabs
The new flash shield needs to be mounted onto the projector. This is accomplished by creating mounting tabs. The methods below will provide rotational, forward/backward, and high/low adjustment.

Bend the leg of the shield 90 degree downward. Place the shield along a straight edge and bend down.
Do the same thing with the H-shape tab. You can then use a dremel spinning wheel to cut the legs. This is how the mounting tabs should look like, after bending and cutting off the legs.
Use a #6 nut/bot and #8 washer to hold the curve shield with the H-shape mounting tab together
to create a mountable shield
Mountable shield at a different angle.
Oem S2K shield Test mount of new custom shield
Top view of Oem S2K shield Top view with custom shield

Test Out Custom Shield And Make Adjustment
The last step is to test it out with your projector. Remember to test it out up close and at far distant. What looks good up close may not be so at distant. There are 4 basic adjustments that you need to take care of. The first adjustment is the rotation. The cutoff beam should be horizontal. This should be easy to adjust, as you simply rotate the cutoff shield. Make sure that the left and right sides of the cutoff step are equally bright and sharp. The second adjustment is to care of the smiling/frowning issue. If the cutoff beam is smiling, tip the cutoff shield back (toward the bulb). If the cutoff beam is frowning, tip the cutoff shield forward (toward the lens). Once the cutoff beam is horizontal and flatly straight, then you need to do the third adjustment. This step involves moving the shield upward or downward. Moving the shield too high up (above OEM setting) will reduce your overall light output. It will make your beam appear sharper only because it is less intense (see pic). Moving the shield too low (below OEM setting) will give you lot of foreground lighting but poor lighting along the cutoff line. This is not good if you're the type of people (like me) who prefer to see your cutoff at far distant. I recommend setting it at OEM height (see pic). The fourth adjustment, which takes care of the color and sharpness. This is accomplished by moving/sliding the shield forward/backward. Here's a generally rule. Moving the shield toward the bulb will give extra blue and sharpness within 15 feet range, but at far range, the blue and sharpness become faded and soft. Moving the shield toward the lens (away from the bulb) will give more yellow and less sharpness within the 15 feet range, but at far range at 50-100 ft, the blue will show up and remain relatively sharp. This is why it is important to test it out up close and at far distant. The color/sharpness adjustment is a personal taste. For me, I prefer a sharper cutoff at far distant where the blue color band is still visible. It makes your beam unique among other cars. It took me several iterations through the four adjustment to get it right.

NOTE: The following shield adjustments are based on an '05 S2K projector with modded shield. Some of the cutoff beams are not perfect or ideal. They are taken to show cases in point only.

Back view of shield. Rotate the shield so that the shield is horizontally even across. Moving the shield up/down
will affect the amount of concentrated light below the cutoff beam. I recommend moving the shield down 1mm
below OEM shield height. This will increase your overall foreground intensity while maintening good
concentration of light along the cutoff line.
Here's a sample where the cutoff shield is not horizontally straight. 25ft from wall. Here's a sample where the cutoff shield is placed higher than the OEM shield height.
Overall intensity get decreased.
Here's a sample where the cutoff shield is placed 1mm below OEM shield height. Note the overall increase in
intensity below the cutoff beam. Also note the concentrated streak of light below the sides.

Side view. If the beam output appears frowning, tip the shield forward. If the beam output appears smiling,
tip the shield backward. After tipping the shield forward/backward, you'll may need to move the shield
backward/forward respectively (to maintain the same distant of the shield from the lens).
25ft from wall. Here's a sample of a smiley cutoff beam. To make the beam horizontally straight,
bend the shield backward, toward the bulb.

Top view looking down. Move the shield forward for sharper and more concentrated blue at further
distant(100ft). Move the shield backward for sharper and more concentrated blue at shorter distant(15ft).
Rotate the shield side-to-side if one side of the cutoff beam is softer/sharper than the other side.
Both sides should be equally sharp/soft (assuming the shield is symetrically curved).
Move the shield side-to-side to center the cutoff step.
At 25ft from wall. Here's a sample where the shield is moved backward toward the bulb about 1mm to get
more blue. At 100+ ft, the blue is still visible, but a bit soft.
Here's a sample where the shield is moved 1mm forward toward the lens. Note there are a mixture of blue,
purple, orange, and yellow. The orange/yellow will become blue/purple at 100+ ft and the beam remains
relatively sharp too (if you're using a clear lens projector).

My Other HID Related Retrofits
Converting a Halogen Projector Foglight Into an HID System (Jun. 2002)
Converting a Stock Reflective-style Headlamp to Projector-style Headlamp (Aug. 2002)
Do-It-Yourself Custom BMW Angel Eyes (Sep. 2002)
Retrofitting an OEM D2 Base Bulb Into an H3 Base Foglight (Nov. 2002)
Upgrading My Angel-Eye Rings With Reflective Tape (Dec. 2003)
Retrofitting a BMW X5 Projector Into Aftermarket Lowbeam Housing (Dec. 2003)
Retrofitting an Audi A6 Projector Into Aftermarket Highbeam Housing (Dec. 2003)
Honda S2000 | Acura TSX | BMW M5 Retrofit Combo (Dec. 2004)
CRX with Honda S2000 and Acura TSX Dual System (zTail Shield Mod + Mirror Mod) (Sep. 2005)
S2000 and TSX Dual Beam Output (Oct. 2006)
Projector Beam Comparison (a6, x5, s2k, tsx, m5, 330xi zkw, tl, sc430, rx330) (Oct. 2006)
Scion tC with S2000 Projector (Prism Tail Shield Mod) (May 2007)
How To Create a Custom Shield for an S2000 Projector (November 2007)

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