Light output JDM vs. non-JDM Options

[Temporary-Failur...]

Can you tell is there big difference between JDM projectors and non-JDM (original? What you would call those ) if we compare light output.

[Galcobar]

Projector designs have nothing to do with HID, or halogen. They're a housing type.

Most HID systems do use projector housings. Many halogen systems use projector housings -- projectors showed up in cars in the 1960s, long before HID came into being. And notably, not all HID systems use projector housings.

The problem is when people combine a housing meant for one type of system with the bulbs from another type. Typically, this means sticking an HID bulb in a halogen housing. Halogens produce significantly fewer lumens (measure of light output), but it's the beam design that's the real mismatch. Headlight housings focus the light output of the bulb; change the location, size, or orientation of the light source and you change where the light ends up. You can't properly aim a halogen housing when using an HID bulb.

Projectors are the most efficient type of headlight housing, as they let the most light through. Least efficient are parabolic reflectors, as they require fairly thick front lenses to focus the light. Complex reflectors are the middle child, using a clear front lens and multi-faceted interior which some people refer to as crystal-clear headlights. Projectors do indeed put out more light than a parabolic or complex reflector of equal quality.

Beam pattern is an entirely separate issue. You can get the same level of control out of a complex or parabolic housing as you can from a projector, but manufacturers who are willing to spend extra to get the efficiency of a projector housing are unlikely to accept a poor beam pattern. Parabolic and complex reflectors being cheaper to manufacture are more likely to be subject to poor design.

The shape of the headlight's output is determined by law. The US standard is the DOT standard, which stems from the 1950s when overhead signs weren't illuminated. The DOT thus calls for a beam pattern where about half the light is thrown upwards, while the rest lands on the road in two distinct hotspots. This is true of U.S. projector housings as well.

Pretty much the rest of the developed world expects overhead signs to be illuminated, so the beam pattern calls for the light to be spread evenly below a flat cutoff, with a tick upwards to illuminate roadside signs, somewhat like this: _____/. This is known in North America as ECE or E-code. The difference is design is why the US didn't get the HID systems for years after the rest of the world did, since putting half the light of an HID system into an oncoming driver's eyes is a bad idea.

It is equally illegal to put an HID bulb in a halogen projector as it is to put an HID bulb in a halogen parabolic reflector. And for that matter, it would be illegal to put a halogen bulb in the complex reflector housing of a Nissan Altima 2.5 SE, as that complex reflector uses HID bulbs. Sticking an HID bulb into a halogen housing, or vice versa, meant for DOT standards produces a misaimed beam pattern with blinding glare.

Projectors were the primary housing choice for HID systems because they emphasized the performance difference between halogen and HID, and because projectors and HID are premium features which add cachet to luxury cars (similar to leather-wrapped and heated steering wheels, each is a feature but combined they spell luxury).

The JDM -- and for that matter, European -- headlights on sixth-gen Celicas used projectors with halogen bulbs. The H in the bulb designation tells you this.

Since the sixth-gen can accommodate projector housings, the best choice is to buy projectors meant for HID bulbs, with the ECE beam pattern. This gives you correctly matched housings and bulbs with the efficiency of a projector housing and the output of HID.