l own a MRS S-Edition year:2001 and was looking at a HID conversion Kit for H4 with a light hint of blue in the bulb but not to strong was thinking of going for 6000K – 8000K Do not know what do you think??? first time using HID lights....


I have heard that for example if you buy a HID Kit with 6000K over its lifetime it will get bluer / darker and reach at the end of the bulbs life 7500K to 8000K is this true???


Also how are they with the NCT if anyone installed them in there car????

I don't know too much about car lamps but they cant be that much different to internal building lamps which don't degrade with age, in terms of their colour temp.

If you install a 4500K fluorescent lamp it will stay that colour until the end of its life. When you replace the flour. lamps in one fitting it doesn't look different to the old lamps around it. That's my experience anyway which may not be applicable to car lamps

I would have to agree with Spanky, not because I know this for fact, but because I have never seen or heard of colour temp degredation before now.

Standard Halogen is approx 4000-4500K (yellow/white), so 6000K is very white and 8000K is white with a hint of blue. I was considering HID's for my MK2, now thinking of upgrading my jeep heads and fogs to 8000K. I have had the same dilemma, 6000K or 8000K, but think I have settled on 8000K now. Great kits for less than 100euro now and some decent shops with good brands will give you a lifetime warranty on the bulb. The true Xenon HID bulbs should last for a seriously long time because they dont run at high temps. Should it fail within a certain timeframe, you get a free replacement.

Otherwise, you can take your chance on a cheap ebay one, but hard to get spares and replacement bulbs etc.

Thanks SWAGGER you are the man,

Thinking off going for 8000K because of the hint of blue, but is that not to blue???

Will have to see them in the flesh first to decide on it and shop around…


Also is there any one with HIDs on their car that passed the NCT if so what type ???

Don't worry about NCT man, most high end cars have HID's fitted from factory. Perfectly legal as long as you don't start going 14, 16 or 20K etc, at that point they go from full on blue to purple. Of course they are illegal. 6 & 8K are fine.
HID's will only fail NCT if they are not aligned properly, and are shining up or to the side too much, same as standard bulbs.

HID only means High Intensity Discharge, so technically, Xenons are HID's. You will find bullshit Halogen bulbs in shops, like H3's and H4's etc, with claims on the packaging that they are xenon white, or HID etc. It's crap. A true Xenon/HID bulb needs a special wiring loom and a ballast to control the more sophisticated electronics. With modern cars you can get OBC (on board computerO errors for the simple reason that most modern cars can sense and tell you when a bulb is blown by sensing the lack of current. Standard Halogen headlights are 55W and HID are only 35W, so if you fit HID's to a car that didn't have them from factory, you need the little units that go in before the HID's and they send a fake 55W signal back to the ECU, eliminating the errors. You shouldn't really need those in an MR2, but they are only like 35quid anyway.

Some of the main differences between Halogen and HID, besides the much higher, brighter and clearer output, is the lower current and therefore, lower running temperature (as opposed to colour temp). This is perfectly logical as 1w of power creates 1w of heat. The reason that HID's run at a lower wattage is simply that 55w is way too much, at that wattage they would be dangerous on the raods, oncoming drivers would be totally dazzled. The last big difference, and the reason why Xenon's are so much brighter AND last WAY longer than Halogens is because Halogens have a filament, which at 55W will eventually burn out. Also, they only have Halogen gas inside. Xenons have no filament, just pure Xenon gas which burns greater at less power.

I could be wrong here, but I believe that the colour output of the Xenon's is not down to the bulb, but actually controlled by the ballast. The only choice you have to make with a kit is to choose what type of bulb fitment your car has, ie, H4 for an MR2 etc and then the colour temp you want. The ballast takes 35W in from the car and controls the output to the bulb by controlling the colour temp from the bulb. When you first turn them on, they are cold and not running at full brightness, but within a matter of seconds, you can see them get brighter as they warm up and the ballast settles the output. They are pretty easy to fit too, you simply plug and play and just find a nice clearing to stick the ballasts, usually tie wrapping them to something.

Sorry for the novel, hope it helps.

Traditional car lamps are the same technology as a domestic light bulb. These are around 10% efficient meaning that the lamp produces 9x heat to light. So, a 55W headlight will be about 5.5W of lighting power and 49.5W of heat. The light is created by electric current causing the filament (usually tungsten) to glow with a bulb of inert gas. These are called incandescent lamps.

Xenon/HID lighting are discharge sources, the same idea as street lighting and fluorescent lighting. In this case a gas is excited by a current supplied to one of two cathodes in an enclosed tube or bulb. Depending on the gas and costings inside the enclosure (phosphorous in fluorescent) you get different amounts of light emitted but with efficiencies at least double that of an incandescent lamp.

Incandescent lamp are self regulating in that the size of the filament decides how much current flows. Discharge lighting requires a controlled current and voltage (i.e. power) to be applied between its contacts, hence the control gear that Swags mentioned.

The colour temp of fluorescent lamps is determined by the coating inside the tube. I don't know about car lamps but I would assume it is the same or linked to the gas. Either way it probably cant be changed once made.

6000-8000K is pretty much simulated daylight. If you go higher than this then you are heading too far into the blue end of the spectrum. In my work we dont go about 4500K(ish) as this is a quite a harsh clinical white light for internal spaces.

Good info Spanker but at least mine sounds like my own words and not Wiki Copy Paste!

Kidding bro, fair play, interesting stuff. You know I like my electronics and gadgets.
I didn't realise that you were in the lighting game, you obviously know this stuff intimately.

OCon click the link below and also click on the links that are on those pages, they will explain about HIDs and their different colours.

www.mr2.ie/mr2-forum/10-general/20214-pa...imit=30&start=30

Thanks ever one for your help but one more Q

Do l needed a Canbus Digital Decoders for the HID Kit for a toyota MRS 2001

(have Xenon Halogen bulb with 100/90w at 4000K that in min without any warning lights or is the Canbus Digital Decoders to regulate the current??? )

I'm not sure on that one. I would buy a goog hid kit and if there was any of the mentioned problems then I would get a Anti-Canbus Error Decoder:

Flickering Lights
Ballast Shutdown
Bulb Warning
OBD Errors
Strobing

Yes I did copy, paste & edit

One final thing I will mention is that I have found out that if a car that was manufactured with HID as standard it has to have a washer to clean the lens and an automatic sensor to contantly adjust the beam angle so not to blind oncoming drivers. However there currently is no mention that an aftermarket HID kit should have the washer and angle adjuster fitted to pass an MOT or NCT test. But don't come crying to me if you get slapped on the wrist by any law enforcers, I am not a solicitor

SWAGGER wrote:
Good info Spanker but at least mine sounds like my own words and not Wiki Copy Paste!

Kidding bro, fair play, interesting stuff. You know I like my electronics and gadgets.
I didn't realise that you were in the lighting game, you obviously know this stuff intimately.

Wiki copy, how dare you

I'm involved in specifying the end product rather than the ins and outs of lamp technology but we have been specifying colour temp for the last few years as it can make a massive difference in the room. In one case I specified two different colour temps in one room (2500K & 4500K) and used an addressable dimming system to create different scenes ranging from something like a domestic lounge (warm light) up to a meeting/office room (cool/white light).

Lol the last post was all my own words. There is actually aftermarket products that can adjust certain lights and wash the lens.

I've been playing around with discharge lighting for a while, both for domestic lighting and for automotive lighting. I've an interest in astronomy, and from that I've got a pretty good understanding of how we perceive colour and how the different lighting sources work, and how effective they are for different scenarios.

When I retrofitted HIDs to my A4's dipped beam and front fogs, I chose 6kK over anything else, as this colour gives more lumens per watt than the 8kK bulbs. I don't like the severe amount of deep violet light that is part of the 8kK light colour in oncoming cars - it creates glare more easily - and I went for the whitest light that I could get. True white light for daylight-adapted eyes is about 5800K, and that shifts to the blue in dusk and low-light conditions (Purkinje effect) so the 6kK to 6.5kK is about right for appearing white.

The colour of the HID output is determined by the mix of metals that are present within the HID capsule itself and cannot be changed afterwards. There may be a colour shift and changes in brightness output in a HID bulb over time and this is why it's usually a good idea to change both capsules if one stops working. I've recently had one capsule fail in the front foglight, it started appearing an off-white colour on sparkup then it stopped sparking up properly. I'll be replacing it soon. Still, one bulb failure in 3 years and about 100,000 km isn't bad going.

Going by the letter of the law, there is no provision for retrofitting HID systems to cars that have not got the correct self-levelling and headlight washers. Theoretically the NCT should fail HID-equipped cars for improper lights unless the levelling and washers are in place. However, I've been through the NCT twice and there was no mention of them. I am severely pedantic about the beam alignment though.

Some cars will throw errors when HIDs are retrofitted as the current required to ignite (sometimes momentary spikes of ~5a) can often exceed the running current of the standard bulbs and then drop back to the 2.5A that each capsule uses once it's warmed up. My A4 picks up the high current spike sometimes as a bulb failure and it pulls the supply to the bulb as part of the bulb-out function of the Audi dash computer. Pain in the ass sometimes, but a switch off, wait, and switch back on works. It does mean that I need the engine running (for the extra 2 volts from the alternator compared to battery power alone) for active fogs.

I'm sorry that I can't answer the question of if the HIDs will work with the MRS. With the relay module it should work no problem, just make sure you put inline fuses in place! Some of the boxes are nothing more than a carefully chosen power resistor in parallel with the ballast, and you end up using the same amount of power even though the HIDS themselves draw less.

Fantastic info Cathal, nice one!

cathalferris .... Karma +1

From looking at cars with various kits i would be going with 4300k as this to me appears to be above yellow and bellow blue in its appearance. 6000k looks too blue IMO but then again i like 4300k because it looks OEM and provides the best lumen.
Most factory HIDs are 4300k