7" retrofit (GDAA WRX)

[satrya]

The GDAA WRX comes with a 7" reflector halogen foglights (H3 55W bulb).


The yellow overlay is stained glass spray applied on a 40 mil clear film. Over time, the spray lost its transparency and became more translucent (hazy).


[ After picture here; if I finish this project ]
Done, as of 20150906:

• Top outer: aux parking light (custom LED housing)
• Top inner: halogen cornering light (ES300 fogs)
• Bottom outer: halogen fog light (Hella Micro DE)
• Bottom inner: aux turn signal (custom LED housing)

[satrya]

OEM vs potential donor

The pictures below show the oem housing vs a potential donor housing. The donor housing is a generic 7" with a dual filament low/high H4 halogen beam + a small city light, which doesn't have mounting points nor a separate reflector - housing assembly.

OEM, front:


Potential donor, front (note the faux projector lens):



OEM, rear (note the 3 mounting points plus 1 combined pitch & yaw adjuster):


Potential donor, rear:

[satrya]

I did some bench and field testing of various halogen foglights, and am convinced that I would want to put a pair of Hella Micro DE (halogen fog pattern) into the donor housing.


The OEM foglight is sometimes criticized for being useless. I think it is just misunderstood. Here's a low exposure picture (ISO=200, 1/250 sec. exposure) to get some idea:


Note how the output is dominantly horizontal, with minimal glare above and minimal foreground. Depending on what you want, I guess it can either be a good or a bad design. Here is the Micro DE under similar camera setting:

[satrya]

Outdoor shots of the oem (ISO=200, 1/3 sec. exposure):


Micro DE (slightly sharper cutoff, slightly more intense on the sides, but more foreground):

[wireless]

Any other cosmetic changes you might make? I'm curious because I really enjoy the work you do..

[satrya]

^
Thanks. Therein lies the problem; aside from the custom mounting of the Micro DE that needs alignment adjustability. I've seen miata-like 7" retrofits here, and pushing that idea of a single beam the tiny size of a Micro DE feels like under utilizing the space.

In one hand, I want to keep the primary components truly functional. On the other hand, it's nice if it has some design touches here and there. I'm looking forward to hearing opinions to keep me from going one extreme way.

[satrya]

OEM foglight removed. The opening can swallow the reflector bowl of most 2.5 & 3" lensed HID projectors... tempting. But I'm going to have the halogen Micro DE as the required element.


Visual mock up of the donor 7" housing in the space. Unlike the OEM, the lens is not slanted to one side.

[satrya]

Trying out the dimensional clearance for the Micro DE. It's micro allright. A bit ridiculous.


Mounting the Micro DE as high up and outside as possible, and possibly aiming a little bit outwards.

[satrya]

One class of usable foglight I know of that is somewhat decent, yet more compact than the Micro DE, is from Hella's budget Optilux line.

Here are the 1182 (black) & 1002 (chrome), both with an uncoated H3 55W halogen bulb that emits a deep yellow thanks to the dichroic coating on the lenses. The 1002 has a slightly deeper bowl, but is still shallower than a Micro DE.






It might be possible to fit the Micro DE next to either the 1002 or 1182, with the Micro DE being the primary foglight. It might go well with the quad look of the headlights.

[satrya]

Comparing the general shape of the oem and replacement donor housings. Again, since the donor housing is a generic low/high beam unit, the lens doesn't have a matching yaw angle that works for my car.


Putting the front lenses together shows the difference in the longitudinal axis of the beam; the generic one points perfectly perpendicular to the lens surface center. I'd like to retain the yaw angle of the oem fog.


There are oem replica foglights that have identical mounting points as the oem, but that would be too easy. Plus I may end up cutting up a lot of the housing, so it seems a waste to get a more expensive unit (~6 times the price).

How should we go about this ...

[Pig In A Poke]

Chop the OEM's Wouldn't bother with the cheapies.

[simkid5614]

I know TRs is making a 7 inch round with HID projectors But it'd be a moot point if the foglights might have better projectors than the headlights.

[satrya]

Chop the OEM's Wouldn't bother with the cheapies.

Since I plan to make a lot of cuts to the housing, I thought that a 6x price difference justifies the extra challenge. If I were to use the reflector optics, then I would agree. Besides, it wouldn't be much of a build thread if it's completely plug and play

I know TRs is making a 7 inch round with HID projectors But it'd be a moot point if the foglights might have better projectors than the headlights.

The thought crossed my mind, but I wanted halogen fog pattern to be in the retrofit. I don't think TRS' 7" HID has any more space to squeeze in even a Micro DE.

I have no plans to change my low/high beam setup right now; with the EvoX-R (with foreground limiter) for freeway driving and Mini D2S (with squirrel finder) for backroads. Both have very good high beam, and have just the right relative intensity for their respective uses.

I do want to add either an auxiliary turn signal, or a DRL, or cornering lights, or auxiliary halogen high beams, in addition to halogen foglights. My hope is that the 7" housing can fit at least the foglight + one more feature.

[satrya]

For convenience, I need to make a mock up of the mounting points (around the bumper area) and important dimensions of the oem foglight so I can work on anywhere far from the car.

This is a mock up cardboard of the flat area in the bumper, with the 3 holes where the oem foglight is secured to.


With the oem foglights "mounted" on the virtual bumper, mark the lowest and highest points of the foglight lens edges relative to the mounting surface. This is to reproduce the right amount of yaw angle of the housing lens of the donor. First, the lowest point. I know it looks like the area where the blue tape has a tear seems like the lowest point, but it isn't. Probably just some foreshortening effect of the closeup.

[satrya]

Find the highest point by running a ruler perpendicular to the cardboard along the oem foglight's circumference. Confirm that the highest point is diametrically opposite to the lowest point. For that, I need to find the center line first.

Find a line going through the center of lens by connecting 3 points made by the corner (red cross) and 2 intersecting lines angled 90 degrees. The intersection of the lines and the circle, marked green, are now diametrically opposed to each other. With any luck, the identified high point should be close to that green cross mark on the right. (low is on the other cross mark)

Connecting them (yellow) establishes a line that goes through the center. Do this several times to get many yellow lines, and the common intersection should be the center of the lens.