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MG TD TF 1500 - Brake Lights Upgrade

Have always been concerned about the relatively low lightr level of our brakes lights. Have seen the third light addition, would rather stay with my poriginal sqaure (1950) light setup. Does anyone have any tricks/suggestions halogens etc ?? checked the archives didn't see anything along these lines
Jon Levine

Jon, if you insist on sticking with the original lights you don't have much available. The exception is to go to modern led bulb replacements. The are some available now that are worth considering. Check the archives of the past year. If you decide to go that route, I strongly suggest that you change over to a negative ground system to save a lot of grief. Bud
Bud Krueger

Bud, here in MN we have someone who makes the lights for the TD in either pos or neg ground. I have them and I am very happy with them. Try BMC British Automobile, Brian McCullough I have no intrest in the co, but they are good and lots of us have their lights on our cars.
Tom Maine (TD8105)

If you clean and bring all connections up to best case. and relay the major feeds, like IGN controlled group including brake lights, you can gain 100% to 200% actual light. This goes for all lights on the car; connections plus relay for the headlamp load takes so much drop out of the circuit that you gain surprising amounts. Checking actual delivered voltage across the bulb filaments will predict; drop should be less than 0.5V off of actual generator output volts, but is commonly as much as 3 or even 4V. Light output is not linear with voltage, but a complex exponential function.

Typical sample lamp delivered voltage:
10.5V : 510 lumens
11.0V : 597 lumens
11.5V : 695 lumens
12.0V : 803 lumens
12.5V : 923 lumens
12.8V : 1000 lumens <--Rated output voltage
13.0V : 1054 lumens
13.5V : 1198 lumens
14.0V : 1356 lumens <--Rated life voltage
14.5V : 1528 lumens

Want more, email, ask for "Electrobabble".

FR Millmore

At the earlier suggestion of Tom Maine on another thread I acquired LED tailights from BMC for my positive ground TF. These new lights perform beautifully. They are much brighter than the incandescent bulbs ever were. Installation was very simple, the directions were refreshingly clear and the vendor was very helpful.

There was discussion on an earlier thread about trying to measure light output of various LED arrays versus other forms of lighting. I do not purport to understand any of it. I would not recognize a lumen if it stood before me. However, based on personal observation I attest that these LEDs are a real and substantial improvement. They cost about $178.00 for a pair. You will also need a new flasher for around $10 or $15 more.
P. Hejmanowski

The Litezupp worked very nicely. The 2 guys there confenced call fixed my problem. The issue is good ground connection. Old flasher worked fine. Incandescent bulbs draw so much juice they overcome a little contamination. Also, I think, they don't overload the newer brake switchs. Kind of gets 2 birds with one stone.
Peter 54TF
Peter Dahlquist

I have one "original" red glass cover and one Moss "replacement" (from PO). The replacement seems to let about twice the light come through than the original! People are always telling me the original side is not working. It works, but just very dim compared to other side. Someday I'll "replace" it!
efh Haskell

Good data, FRM. Light measurements were my bread and butter for a whole bunch of years before getting retired by Polaroid. The rule of thumb for light output variation as a function of applied voltage is that it varies as the 3.5 power, i.e., (Vapp/Vref)^3.5. Note that your 1000 lumens at 12.8 volts goes up to 1356 at 14.0 volts, about an increase 10 % in voltage giving about an increase of 35% in lumens. BTW, lumens are to light like gallons are to water. Bud
Bud Krueger

Yes. Light data from Daniel Stern Lighting. There is a 13th power factor in the base calcs that result in that rule of thumb.
Note in the story below that 9.6V is about enough to find the light on a dark night if it is on!

I have measured data on actual voltage delivered across the filaments and it is truly appalling on nearly every car that I have not fixed. Aside from the pure safety aspect, it is my belief that many people do not use their cars as much as they should because without knowing it, they are uncomfortable because they can't trust the car from electrical failure, and if it does start and run, they can't see. Can't tell you how many guys say they don't go anywhere that keeps them out after dark because of their "eyes". One customer started yelling at me when I measured his MGB at 9.6V at the headlamp bulbs, and his Geo Prism at 10.2 or so; he had had several serious eye doctor checks, and was scheduled to check in to a hospital for extensive major testing because he couldn't see at night but they could find nothing wrong: "and NOW YOU are TELLING ME MY EYES ARE FINE IT"S MY WIRING???" It was too - I fixed the connectors and he got home in the dark and cancelled the hospital. That was so much fun he then told me to do the rework, relay, extra fuse thing, plus E-code H4 lamps. Then he drove home and called immediately "Hate it. Now people flash their lights at me all the time and I have to use the dimmer switch, which I haven't used in the 15 years I've had the car."

Need to emphasize here that my approach fixes the whole car electrical system, with beneficial effect on many attached items - ignition, all accessories, wiring harness - the heat of loss is the same heat that will set it on fire, and most important is the mental effect of some clear thinking. LED lights and majic potions do not correct or improve any of those things.

FR Millmore

I installed Halogen bulbs a few years ago, much brighter, no problem with turn signals or brake light switch (yet). George
George Butz

Good story FRM-
you need to change your signature to: FRM DO
Dallas Congleton

Fletch, the '13' exponent occurs in blackbody radiation computed from the use of Max Planck's constant, where c1=5.953 * 10^(-13)^2. Bud
(Measurement of Optical Radiations, The Focal Library)
Bud Krueger

Dallas -
And my prices!

Bud -
Indeed, but having Daniel's excellent chart, not only do I not need all a them funny little numbers, I have a chance of getting the point across to those who go crosseyed at 2 + 3 = 11/2 - $0.50!

George -
Measure the hot 2000rpm running voltage across the light filaments, then see chart above. Both head and stop/tail. Report.

FR Millmore

There is a great article about this very subject in the August TSO. It is being printed now, will be in the mail soon. It explains what is out there for LED bulbs, brighter headlights, etc.
D. Sander

For those that didn't ask for it ...IMHO:
Fletchers "Electrobabble" is an excellent read!

For those of you with a TF1500 (or those inclinded to add the "tub reflectors" found on them...Moss sells them) I found that to be a great place to add some "higher" lighting to be seen.

(This assumes the suv behind you can put the phone down long enough to actually "look".)
David Sheward

Thanks for the physics updates, the Plank constant puts it all into perspective! No doubt low voltage is why my 280Z's headlights are so dim. Not so easy to work on and no fun compared to the TD however.
George Butz

It is illuminating to measure voltz!

FR Millmore


If you don't wish to take the above advise, there is another "trick" I have used on MGA's and now on my TD. Clean the reflector as much as you can and then buy a can of spray chrome (most hardware stores have them) and spray this on the reflector. I have been asked many times how I got such bright lights! This is a small and inexpensive trick but sure makes a big difference.

Brian Smith (1950 TD3376)

And in addition to Planck's constant don 't forget to factor in the Higgs boson now that it' s finally been found.
Mike Fritsch

Wow Bud, You just made me do a double take!

It amazes me that two entirely different industries can use the exact same terminology for wildly different things.

In my business Vref is the aircraft zero wind approach speed - Velocity, reference. Normally 1.3 X Vso or the power-off stall speed in the landing configuration.

Vapp,(Velocity, Approach), is the reference speed corrected for wind conditions used for the aircraft approach. Itís normally Vref + 1/2 steady state wind + the gust factor.

Strange, isnít it?

JE Carroll

This thread was discussed between 16/07/2012 and 19/07/2012

MG TD TF 1500 index

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