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Headlights: The Truth Illuminated: What works and what doesn't
There is a general dislike for the headlights on the C5 corvette and other older cars that use aged headlight technology consisting of a halogen light source and a poorly designed reflector and lens. IN my experience such headlights make night driving dangerous due to poor visibility especially on rural or unlighted streets.
There is undoubtedly a demand for better performing headlights, but with so many choices available, many people simply do not have the time to research the subject enough to make a well informed decision. The purpose of this article is to explain the options and how each of them works, their strengths and weakness so that the reader will be able to make the best decision possible.
Section 1: Why the factory headlights are inferior.
The C5 corvette uses the same old style of headlights that have been use since it was introduced in the 50s. A 9006 halogen bulb with 1000 lumens of useable output provides the light source and sits inside a reflector bowl with light being focused by the various contours of the lens. Using a lens to adjust the light pattern is horribly inefficient since the light beams have to be augmented and bent to achieve the desired pattern. Light looses energy as it passes through the augmenting lens surface. In the C5, the lens is plastic and is prone to fading over time which further diminishes light output. The result is a headlight system that is more like a candle.
Section 2: Headlight options:
Modern headlights use a variety of lenses reflectors and light sources to achieve better output than the sealed beam halogen lights of a few decades ago. The options available for the C5 include (in order of cost)
1: Aftermarket/high wattage headlight bulbs.
The simplest way (and least effective) to increase the effective output of one's headlights is to install a set of aftermarket bulbs. Many companies claim a special gas or "HID-like" color that gives of much more light than factory bulbs. The truth of the matter is there's no such thing. To make more light, you either need a hotter filament (which draws more wattage) or more gas (Toshiba/Philips HIR bulbs). Most aftermarket bulbs that use the same wattage as the factory bulbs will have a blue tint to the bulb to simulate a whiter light. This blue tint actually decreases output by filtering out the yellow frequencies of the light emitted by the burning filament. You can read more about blue bulbs here:
Another trick bulb makers use is to have higher wattage aftermarket bulbs. This can produce a dangerous situation as the Factory wiring was designed for a 55w bulb. Running a 100w bulb might work for a while, but the wiring is not designed for this type of load. The end result can be as simple a fuse popping or as dangerous as melting wires or even a fire. The only safe way to run higher wattage bulbs is with a relay circuit designed to carry the higher-amperage load required.
The ONLY type of bulb that produces significant results on factory wattage in the factory headlight is the toshiba/phillips HIR bulb (characterized by their "fat" glass bulb. (shown below)
The price of these bulbs and the rather limited improvement on headlight performance makes them a questionable purchase compared to other options.
2: HID replacement bulbs
The biggest rage in Headlight performance is the use of HID bulbs in the factory headlights. HID bulbs use the same or less wattage as factory bulbs while producing nearly 2-3 times the amount of useable light. In addition, the customer can pick the color produced by the bulb without losing a significant amount of output (between 3000-6000K). These are the ultimate light source but they come with a few drawbacks.
a) HID bulbs installed in housings not designed for them are illegal in many states.
b) The factory lights were engineered to focus the limited light from a halogen bulb source. HID bulbs overpower that design resulting in glare
Most people will never have to deal with getting a ticket for illegal headlights, but anyone whose installed a set of HID bulbs in their factory headlights will deal with the second issue. Factory lights build around a halogen bulb are designed to use the limited light from a halogen bulb (typically 1000-1200 lumens from a low beam) into the most useable pattern possible (which often means sacrificing long-distance vision so drivers can see some of the road immediately in front of them. Installing an HID light source produces more light, but all of this light is focused in the same area creating intense glare for both the driver and other traffic. This glare reduces visibility as too much light from the foreground is reflected back at the driver. In addition, the output pattern is typically scattered and sporadic making it very difficult to see the road clearly, much less anything on it.
3: Projector headlight system
The way to tame the power of the HID bulb is to install it in a projector headlight system. This means replacing your entire headlight assembly. This is often one of the most expensive and time consuming options, but the results speak for themselves. When installed in a projector, the HID light source produces an wide, evenly distributed light pattern that allows for reasonably decent road illumination on even the darkest roads, but this setup can still be improved upon. Most Aftermarket headlight system use a very simple to build projector that has a relatively narrow beam, and poor optics. If you want the ultimate in headlight performance, you need a purpose build Bi-xenon projector retrofit.
4: Bi-xenon Projector headlight system
Both of the headlight systems I currently offer are based on the Bi-xenon projector designed and developed specifically around the H1 HID bulb as a light source. Here are some of the benefits compared to most projectors.
1. The Bi-xenon projectors I use have a compound curved reflector bowl (instead of the cheaper to produce round bowl) which produces a wider and more focused pattern. This focuses most of the light along the top-center of the cutoff which is what gives superior long-range vision. In addition, the cheaper projector has much more foreground light which hampers distance vision.
Typical projector: no distinct focus of light, just a simple cut-off
Radioflyer's Bi-xenon projector: very distinct central hot-spot that fades to the edges:
Light that is projected further away on the road reflects back less light because of the angle at which the light beam hits the ground as well as the amount of reflected light that is directed back at the source. (described below)
Radioflyer's Bi-xenon Projectors focus the most intense portion of the beam at the top-center of the pattern. This is the part of the pattern that is aimed furthest away.
Cheap projectors typically have more intense foreground lighting in their pattern which hampers long-distance vision.
2. Our Bi-xenon projectors have a curved cutoff shield resulting in a sharper wider pattern. Traditional projectors have only a flat cutoff shield that is simply cheaper to produce. The Bi-xenon projector's curved shield and bowl can result in 16 degrees more useable pattern width. At 50 feet, this is equal to an additional 10 feet of beam width allowing you to easily see objects on the side of the road such as children or animals BEFORE the cross the road.
Original ACA Projector: (also note large amount of foreground glare just in front of the light housing)
Radioflyer's Bi-xenon Projector: (Substantially much less glare in front of the light housing)
3. The Bi-xenon projector features a solenoid-operated cutoff shield that allows for full-beam spread instantly without needing a second bulb for high beams. This circuit draws very little power (usually a fraction of an amp) and instantly gives you a high beam pattern. There is no delay waiting for secondary HID high beam bulbs to warm up since the HID light source is already in use.
Low beam pattern on wall
Low beam pattern on car from driver's seat
High beam pattern on wal
High beam pattern from driver's seat.
Radioflyer Innovations is the ONLY source for Bi-xenon projector headlights available in the Pop up version as a modification to the ACA headlights or in fixed headlights as the Stealth Light Cannons.
I hope this helps to clarify the options to those of you seeing illumination. If you have any questions, comments or concerns, please post so others may see and benefit from the responses.
I don't drive a lot at night but I find the original headlight system to be perfectly fine for average driving, especially when you search headlight mods and find all the trouble that people have with them. Pretty expensive also.
They do get them right after awhile but there always seems to be wiring/switch/delay issues that effect actuall every day usage. I think the only mod I was interested in was a re-wire to run the low beams in conjunction with the high beams.
It's pretty open where I live so maybe in other areas it has a better payoff. Just my 2cents
Radioflyer Innovations is the ONLY source for Bi-xenon projector headlights available in the Pop up version as a modification to the ACA headlights or in fixed headlights as the Stealth Light Cannons.
I couldn't tell--does this kit include a shroud around the lamps?
I don't drive a lot at night but I find the original headlight system to be perfectly fine for average driving, especially when you search headlight mods and find all the trouble that people have with them. Pretty expensive also.
They do get them right after awhile but there always seems to be wiring/switch/delay issues that effect actuall every day usage. I think the only mod I was interested in was a re-wire to run the low beams in conjunction with the high beams.
It's pretty open where I live so maybe in other areas it has a better payoff. Just my 2cents
Switching to H-4 was a decent deal . About 300 for glass housings and made relay wiring myself. Bulbs are cheap and last 2-3 years. I have 100/130's
Quick testimonial on the bi-xenon projectors from George.
My headlights over the years in my 2004 Z06
OEM halogens
to
HID bulbs in factory housing
to
Radio Flyer Light Cannons
to
Radio Flyer bi-xenon projectors
By far the projectors are leaps and bounds ahead of anything I have used in the past or seen on other C5 Corvettes. They rival the OEM BMW lights on my wife's E60 535.
This past August while driving with a C4 Vette on back mountain country roads in the pre-dawn hours. I was following the C4 with my lights on. I used my FRC radio to speak to the driver of the C4 in front of me and asked if my lights were bothering him in his mirror. He replied, NO and that he didn't even need his headlights on, because mine where doing such a good job of lighting up the road in front of him! It was funny driving while casting a shadow of the C4 Corvette as we drove down the road. The lights are simply awesome, and worth the money in my opinion.
09-17-2012, 03:22 PM
Headlights: The Truth Illuminated: What works and what doesn't
